The DCMGA Help Desk answers lots of questions. Here are a few of the ones we answer most frequently. Contact our Help Desk if you have a question that’s not on this list: Help Desk Page.
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- Annuals & Perennials
- Fruits & Nuts
- Gardening Know-How
- Grass & Turf
- Groundcovers & Vines
- Insects & Pests
- Irrigation & Water
- Landscape Planning & Design
- Soil, Compost, Mulch
- Vegetables & Herbs
A: So glad you asked. Providing nutrients and shelter for bees is increasingly important because much of their natural habitat is being lost due to our rapid growth and development. An important strategy to attract bees is to add plants that flower at different times of the year so that nectar and pollen are consistently available.
The August 2021 monthly Denton County Master Gardener Association’s virtual educational presentation was “Welcome
Pollinators to Your Yard.” The complete presentation is posted to our YouTube channel or you can view it by clicking here: https://www.youtube.com/watch?v=veN7JztMEIQ
The U.S. Forest Service tells us that bees like flowers that are bright white, yellow, blue, or UV and have a shallow or flat landing platform. A great resource to find native plants that invite bees to your yard is the Ladybird Johnson Wildflower Center. They provide an extensive list of Texas native plants and for each one, the description tells you which pollinators the plant will attract and when the plant is in bloom. There is an entire section of their native plant database for North Central Texas.
There are many plants on the Ladybird Johnson Wildflower Center list. To keep from getting overwhelmed, you can restrict your search by sun requirements, flower color, and bloom time. For example, information about the Blackfoot Daisy tells you that it is a perennial that grows 6 to 12-inches tall, in full sun to partial shade, blooms from spring through fall, and provides nectar for bees.
The Native Plant Society of Texas offers an excellent overview of Texas’s native bees and recommends The Pollinator Partnership Guide to find a list of plants specifically for your area based on your zip code.
Bees also appreciate a water source and will visit your yard often if you provide a shallow container with places to stand and rest. “Good systems include shallow birdbaths or pot bottoms filled with water and pebbles or corks. These allow the bees to stand and drink; they’ll generally dry out too quickly for mosquitoes to be an issue.” according to Christine Casey, University of California-Davis.
One quick reminder: if you have to spray a pesticide or other chemicals, please do so carefully when bees are not foraging. Best management practices to protect bees from pesticides.
Texas North Central Recommended
Native Bees in Texas
Ecoregional Planting Guides
Best management practices to protect bees from pesticides
A: Lord Baltimore hibiscus (Hibiscus moscheutos), also known as Rose Mallow, is a shrub with huge, beautiful red flowers. It is native to wet, marshy areas in the southeastern United States. They bloom from August to October with multiple flowers per plant, each flower lasting only 1 day.
I suspect your plant may be suffering from several issues:
Thrips are tiny, slender insects with fringed wings. They are likely eating on and damaging the buds at a young age. To control thrips, apply a contact insecticide every 7 to 14 days, thoroughly covering the buds, shoot tips, and any other areas showing damage. Organic options include insecticides with active ingredients azadirachtin, insecticidal soaps, horticultural oil, neem oil, and pyrethrins. Spinosad is more effective than these. Mix it with horticultural oil to increase its persistence within the plant tissue. This link from the University of California provides more information on thrips: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7429.html
Hibiscus moscheutos require wet to consistently moist soil to thrive. Your plant may be suffering from leaf scorch if the soil is drying out between waterings. Inadequate moisture can result in scorch symptoms on foliage, stunting, leaf yellowing, leaf drop, and flower bud death before bloom.
You could also have a fungal issue. In all cases of plant diseases, practicing good sanitation is important to avoid spread:
- Pick up and discard any plant debris and remove infected leaves, do not compost these.
- Clean tools that are used to prune diseased plants with a weak solution of bleach, rubbing alcohol, or a disinfectant.
- Don’t let the mulch touch the stem to prevent Southern stem blight.
Treat with a fungicide at the first sign of the disease following the label directions for the first and subsequent applications. Please carefully read the label to be sure it’s suitable for hardy hibiscus, and carefully follow the application directions and safety precautions. This factsheet from the University of Florida lists fungicides that are suitable for ornamental plants: http://edis.ifas.ufl.edu/pdffiles/pg/pg08900.pdf
This website from North Carolina University has more info about Hibiscus moscheutos: https://plants.ces.ncsu.edu/plants/hibiscus-moscheutos/. This website from Clemson University has more general information about hibiscus: https://hgic.clemson.edu/factsheet/hibiscus/
A: What a heartbreak to see such a beauty fail so rapidly. Diagnosing disease from photos alone is a challenge; however, the most likely culprit is cotton root rot (Phymatortrichum omnivorum). Rose of Sharon is highly susceptible to the fungus, which is active during this time of year and advanced by overwatering. Is it possible that you could be overwatering in an attempt to save the shrub? Or could there be an irrigation/pool leak in the area?
Before giving up on your plant, first, correct any water or drainage issues you may have. Run each zone of your irrigation system for a minute or two. Put on your raincoat and wellies and look closely at each sprinkler head and your entire drip line. Sometimes water will spew like a geyser; other times, you’ll see bubbling water at the base of sprinkler heads or a flowing stream from your drip lines. If you see leaks or misdirected sprays, correct them. Do this check every month you use irrigation.
Next, get into the habit of checking soil moisture before running irrigation. Use a screwdriver to probe the soil to a depth of 6-8 inches. If you’re able to probe to that depth, moisture is sufficient and no watering is necessary. Alternatively, invest in an inexpensive (<$5) soil moisture meter, and spot-check your landscape before watering (to the same 6-inch depth).
If you’re not able or inclined to manually check the soil, or if you travel, then consider upgrading to a smart controller. It uses your local weather station’s current evapotranspiration (ET) readings to calculate irrigation. (ET refers to evaporation that comes from the soil itself as well as from the plants’ leaves.) The controller doubles as a rain/freeze sensor, shutting off when temperatures drop below freezing or when local rain exceeds a set threshold. Once installed and linked to your WiFi, these smart controllers can be programmed and adjusted from the controller itself, or from your smartphone, tablet, or computer.
The following document describes how to possibly save ornamental plants suffering from cotton root rot by using ammonium sulfate to acidify the soil, creating an unfavorable growing condition for the fungus. This option is a last resort, but it is inexpensive and fairly easy, so it might be worth a try. The downside is that you’ll have to continue acidifying the soil every year, which may become tiresome. In short, prune the shrub back. Build a ridge of soil about four-inches high around the tree’s drip line. The circumference of the ridge-line should be equal to the diameter of the crown/top of the tree. Work into this soil one pound of ammonium sulfate for every 100 square feet of the area within the ridge. Fill the ridge with water to a depth of four inches. Repeat this treatment five to ten days later. Limit treatment to twice per season. Refer to the section at the end of the article entitled “Fertilizer Applications.”
If your shrub dies completely, and you wish to replant another Rose of Sharon, do not replant it in the same location, since the fungus remains active in the soil for years. Instead, plant it in a sun/part-sun location where drainage is excellent. These beauties like moist soil, but not standing water. In its place, plant a flowering shrub resistant to cotton root rot (see link below).
Cotton root rot: https://bexar-tx.tamu.edu/homehort
New Rose of Sharon varieties: https://agrilifetoday.tamu.edu
Trees, shrubs, and flowering plants with resistance to cotton root rot:
- Sharp tool for taking cuttings
- Rubbing alcohol to clean the blade between each cut
- Dark, water-resistant bag and wet paper towels to keep your cuttings moist until you “stick” them
- Clear, plastic containers for growing the cuttings. A clear, plastic bag if your container has no lid. (Empty two-liter bottles or produce containers work well, or even small pots you have lying around)
- A tool to cut the 2-liter bottle and puncture the plastic (pocket or utility knife)
- Dibbler to create a hole in the soil (disposable skewer or chopstick)
- Old tray for a drip pan
- You don’t really need duct tape. It just made for a good story.
- Required: Propagation media (Inexpensive commercial products are available or you can make your own media using half peat moss and half perlite, vermiculite, or coarse sand.)
- Optional: Rooting hormone powder (contains a chemical that mimics growth hormones in plants. However, since verbena are vigorous growers, you should be successful even without the hormone.)
- Small cup, if using rooting hormone (to hold a small amount of the product. Never dip cuttings in the original container or you will contaminate it.)
- Make sure your verbenas are actively growing and not under drought stress. In early spring, they should be in the softwood growth stage, which is optimal for in-season propagation.
- Prep your MacGyver’d containers and propagation media before taking the cuttings.
- The 2-liter bottle can be cut horizontally in half to create a “greenhouse.” Puncture the bottom of the bottle a few times for drainage. Plant your cuttings, then replace the top half of the bottle for an enclosure. The produce container needs similar drain holes, and its lid will serve as the enclosure. For small pots, seal them entirely in a plastic bag. Blow air into the bag before sealing to keep the bag from touching the cuttings.
- Put enough media for your project into a bucket. Add a cup or two of water, stirring until evenly moist, but not saturated. Add more water, as needed. When squeezed in your hand, the media should lightly ball up, but not drip. It is better to slowly add small amounts of water than to have to drain excess. Put three inches of media into each growing container and pat down.
- Take cuttings in the early morning, if possible. Cut just below a set of leaves, making sure the cutting includes two or three sets of leaves. The cutting should be four to six inches in length.
- “Stick” your cuttings as soon as you can. (If delayed, place your bagged cuttings in the refrigerator for a day or so.)
- Snip away all but one or two sets of leaves. Clean the snippers (or scissors) with alcohol between each cutting.
- Dip ½” inch of the cut end into the rooting hormone, if using. Tap away excess powder.
- Use your dibbler to create a hole in the media; carefully insert the cutting so as not to dislodge hormone powder. Press firmly.
- Several cuttings can be placed in the same container, a couple of inches apart.
- Once you’ve planted the cuttings, they must be fully enclosed to retain moisture. Use the lid that came with the box or a plastic bag.
- Place in a bright location, away from direct sun.
- Check daily for moisture level and signs of rot. Expect a little condensation on the container; the soil should remain moist. Remove any cuttings that appear moldy or struggling.
- After three weeks, lightly pull on the cuttings. If you feel resistance, you likely have roots and can “pot up” the cutting into a larger container.
- Potted-up plants should be hardened off gradually over 7-14 days before being planted in the garden.
Answer: Garden gambling with years’ old bougainvilleas shows serious nerve, but if you’re willing to risk losing the wager, I’ll offer suggestions to increase your odds.
Ordinarily, I would never encourage a home gardener to put tender tropical plants at risk. Native to South America, bougainvilleas enthrall us with colorful bracts dotted with tiny, white flowers. Forcing these beauties into dormancy when the show’s not over is a frustrating discipline; however, as in most instances of deferred gratification, you will almost certainly enjoy healthy plants next spring.
As a compromise, would you consider moving the bougainvilleas inside and placing them near a south-facing window for a few weeks? This step will allow you to enjoy the color, without risking plant loss. The bracts (which are actually leaves) will inevitably fade, then you can shift the plants to the garage.
If no indoor space works for your bougainvillea, study the following links to hedge your overwintering gamble:
Overview of bougainvilleas, including frost/freeze protection
This link was written for the Austin area, but it still contains information that should be helpful for you.
Note especially pages 5 and 6 for frost/freeze protection techniques
A: Yes! A number of Texas Superstar® plants provide value and beauty throughout the heat of our North Texas summers. Texas Superstars receive the designation because they are the toughest, most reliable, and best-looking plants studied extensively by Texas A&M Agrilife Research and Texas A&M Agrilife Extension Service.
The selections listed here either bloom continuously from spring to fall or their foliage remains attractive during the same time span. Long-blooming annuals and multi-season perennials need regular fertilization. Some benefit from timely deadheading of spent blooms/seed heads or occasional light pruning, although a few are carefree.
In comparison to annuals, perennials will be more expensive, but they will provide many years of beauty. Perennials also may grow slower than annuals, so be patient if they seem sluggish … they’re not. Remember this phrase about perennials, “First year, they sleep; the second year, they creep; the third year, they leap.” However, the perennials listed here will bloom their first year.
View the list and additional resources on our Facebook page at
or the DCMGA website at
A. Yes, your Amaryllis can bloom again with some basic care. First, after the flower has died, cut the stem within an inch of the bulb. Gradually discontinue watering the bulb as the foliage dies down. Once the leaves have died down you can put the bulb in a cool dry place or plant the bulb still in its pot outside in part- shade.
If you have decided to keep your bulb in a cool dry place, replace the soil and thoroughly water once growth begins again or in late fall, whichever comes first. Water regularly and feed with a complete liquid fertilizer every 2 to 3 weeks. Your Amaryllis should bloom within 6 to 12 weeks.
If you replanted your Amaryllis outside after the holidays, they do not require much attention during the summer. Bring it inside in late fall and begin watering regularly and feeding with a complete fertilizer every 2 to 3 weeks and watch your Amaryllis bloom.
Here is everything you ever wanted to know about amaryllis:
East Texas Gardening – Amaryllis Care
Oak Trust Library – The Amaryllis
A: Cool, spring weather coaxes to life a pesky fungus called Taphrina caerulescens, commonly known as oak leaf blister. Affected oak leaves become deformed with bulges and twists. They develop yellow spots that eventually turn brown and feel papery. Sometimes, you’ll notice heavy leaf drop; other times, the diseased leaves remain on the tree. Also, in spring, live oaks experience natural leaf drop, which contributes to our impression that the disease alone is causing excessive leaf loss when it is actually a combination of the two.
An unsightly condition, oak leaf blister rarely harms otherwise healthy trees. No fungicidal treatment is needed unless your tree has lost a significant amount of leaves. Even then, it is too late this year to manage chemically. To prevent the problem from returning next spring, apply a recommended fungicide in late winter, just prior to bud break (late February). Treat again as soon as new leaves appear. Two or three weeks later, spray one more time. This preventive fungicide should protect the young and most vulnerable leaves during the cool, wet weather favored by the fungus. Mature leaves are not affected by oak leaf blister. Again, most trees will not require this intervention, only those with severe defoliation.
Do not trim infected leaves from the tree. Oak trees pruned between Feb. 1-July 1 may be susceptible to a fatal disease called oak wilt, which is spread by beetles active during this time window. Rather, simply rake up and dispose of all fallen leaves to lessen the fungal presence. Then, put it on your calendar to start fungicide treatments late next winter. If the trees are too large for you to treat, contact a certified arborist in your area for assistance. Many will make a free site visit to give you a quote; others charge a trip fee for the estimate. Make sure to ask.
For those trees most affected by the fungus, make sure to guard against further stressors. For example, provide proper irrigation this spring and summer (one inch every 7-10 days). Look closely for the presence of pests or other diseases, and intervene as recommended by science-based sources, like Texas A&M and other US land-grant universities.
Locally, the Denton County Master Gardener Help Desk is a free service staffed by well-trained volunteers. Reach out via e-mail at email@example.com or by phone at (940) 349-2892. Alternatively, access the free Cooperative Extension web resource called “Ask an Expert” at https://ask.extension.org/ask. For those who prefer audio learning, the Texas A&M Forest Service offers a weekly podcast entitled Trees Are Key, hosted by Paul Johnson, the Urban and Community Forestry Coordinator for the Texas A&M Forestry Service. Use this link to listen to the podcast: https://tfsweb.tamu.edu/podcasts/treesarekey/
Use the links, below, to learn more about oak leaf blister and proper tree care.
Oak leaf blister overview, including recommended fungicides: http://agrilife.org/plantclinic
This article mentions where new buds will emerge on the branches and includes a labeled picture. Look for the photo captioned “New buds on live oaks”: https://plantclinic.tamu.edu/factsheets
Find a certified arborist near you: https://www.treesaregood.org/findanarborist
This link gives reasons for hiring an arborist and lists their scope of work: https://agrilife.org/treecarekit
USDA’s tree owner’s manual is an excellent resource: https://www.fs.usda.gov
A: Both of the arborists could be correct. On the issue of root rot, post oaks prefer well-draining soil. They suffer from continuously wet soil as well as from wide fluctuations in moisture. However, since your tree is on a hill, “wet feet” are less likely, but wide variation in moisture is still a concern. You can use an inexpensive soil moisture meter to determine if your tree needs irrigation or if you should withhold watering for a time.
The Tubakia dryina fungus is a strong possibility. Typical in late summer/early fall, this fungal pathogen requires no chemical treatment. It will not kill your tree, but it is unsightly and may signal a stressed tree. To help prevent future infection, clear fallen leaves frequently. By removing the leaves, you will lessen the number of spores that can overwinter on your property and impact your tree next year. The leaves can be composted, but care should be taken to ensure that the temperature reaches 140 degrees to kill the fungus.
Stressed trees are more likely to succumb to the disease. Think through what might have stressed your tree during the past few years.
- Irregular moisture? (Monitor with an inexpensive moisture meter and adjust irrigation, if possible.)
- Heavy clay soil that drains slowly? (Consider aerating the root zone and topdressing lightly with compost. Plunging a screwdriver fully into the ground every few inches should work to aerate; no need for an expensive process.)
- The root flare is covered by soil or mulch? (Gently clear away the soil/mulch from the trunk, exposing the flare. You can suffocate a tree by covering its root flare.)
- Lack of fertilization? (Have your soil tested; see below.)
Regular lawn fertilization should provide sufficient nutrients for your tree. However, if the tree doesn’t receive fertilization, you may want to send a soil sample to Texas A&M Soil Testing Laboratory to determine the soil’s pH and its percentage of nitrogen, phosphorous and potassium. The lab will give recommendations for the quantity of each nutrient, if necessary.
Refer to the links, below, for more information on Tubakia and tree care.
Tips on preventing future infection (start now)
Fertilization of woody ornamentals and trees (wait until late winter, if needed)
Soil analysis form (to determine if fertilization is necessary)
A: The DCMGA Help Desk has recently received a significant number of calls about post oak trees dying in what appears to be a short period of time. Ms. Sheila McBride (TPDDL diagnostician) and Dr. David Appel, Extension Plant Pathologist with the Texas A&M AgriLife Extension Service, believe the “phenomenon of rapid decline of post oaks is a result of varying extremes of soil moisture (drought and/or drowning) leading to attack by root rots, cankers, and woodboring insects.” “Post oaks are a type of white oak, which are very susceptible to site disruption and rapid environmental changes.” (Kathleen Phillips, AgriLife Today, September 20, 2016)
Root rot can develop as a result of saturated soils (poor internal soil drainage) resulting in inadequate oxygen diffusion to the tree’s root system. All of these problems were made worse by the historic drought of 2011 when the health of these trees was crippled to such an extent that they are still suffering today. The heavy rainfall during the spring of 2016 and again during the spring of 2019 followed by a very hot dry period combined with poorly drained soils are contributing to their demise.
Ms. McBride and Dr. Appel report being confident the cause of the death of post oaks is NOT oak wilt. Oak wilt targets primarily live oaks; this situation is impacting post oaks, which are very resistant to oak wilt.
Your best course of action is to contact a certified arborist as soon as possible to discuss diagnosis, treatment, dead tree removal, and ongoing care and maintenance of your post oaks.
In the meantime, maintaining even soil moisture availability in and around the remaining intact root system will assist in tree recovery. In the absence of rain, water deeply applying two inches once a month to encourage deeper rooting of your trees. Apply soluble high phosphorus and high potassium fertilizer into the root zone to supply developing roots. Do not prune or remove dead limbs from the trees while they’re under stress, rather, wait until they’re dormant.
Texas A&M AgriLife Extension, The Care and Feeding of Post Oaks
Texas A& M AgriLife Extension, Rapid Decline of Oaks
International Society of Arboriculture, Find an Arborist
A: When pomegranates arrive in the produce department every fall, I find myself distracted by a flurry of thoughts: I need to plant pomegranates. I should have already planted pomegranates. I bet a bowl of pomegranates on my holiday table would be beautiful. I need to plant pomegranates. It’s a mad cycle, I tell you.
Lucky for you and me, this is the perfect time of year to plant pomegranates. (January-March) These delicious show-stoppers are self-pollinating, growing both male and female flowers on the same plant; however, they will bear larger fruit if cross-pollination is possible or enhanced. Studies are showing that three cultivars do best in north Texas: Al-sirin-nar, Salavatski, and Russian 18. Plant in a sunny spot on the south side of your property for best fruiting.
Plant pomegranates, and any fruit tree for that matter, with a measure of patience! It will take three to four years for the shrub to begin bearing fruit. In the interim, follow the care guidelines listed in the first linked article, below.
For the first few years that your young pomegranates are in the ground, I would recommend carefully protecting them from freeze and frost. The second link, below, lists a variety of ways to protect young plants from cold damage.
So, let’s plant now to fend off the otherwise inevitable “pomegranate regret” that plagues some of us in the produce department every fall.
A: As a child, I relished picking fresh, wild blackberries, warm from the sun! A wonderful option in North Texas, cultivated blackberries delight the senses just as well as the wild ones, with less aggressive growth. The thornless variety recommended for our area is Natchez, a semi-erect plant that requires some simple trellising in the second year. Late winter is the right time to put in root cuttings, but dormant plants can be planted anytime, although early spring is optimal. Blackberries need excellent drainage, so you may need to plant in berms of compost-amended soil.
With regard to aggressive growth, it would be best to corral these vigorous plants behind in-ground metal edging or another barrier and to pull any young shoots from undesirable locations. Make sure to keep branch tips away from the soil, as they will propagate themselves via this “layering,” as well. The cultivated varieties are not as aggressive as the wild, thankfully, but as with any hardy plant, you’ll want to keep a watch on its growth.
The articles below offer excellent recommendations.
A: Your peaches may have been infested by plum curculio larvae. A common problem in North Texas peaches, plum curculio beetles also target plums, nectarines, pears, and cherries.
These beetle-like flying pests are about one-quarter inch long with a curved snout. Their legless larvae are white or yellow and about one-half inch long. The adults overwinter in wooded locations and move into fruit trees in spring. The adults feed on the developing fruit, wherein females lay their eggs. The resulting larvae feed inside the peach and later emerge as adults, poised to infest fruit later in the spring and summer.
Affected fruit sometimes falls from the tree but can also remain attached, often appearing deformed or misshapen (cat-faced). All fallen fruit should be collected, and fruit showing cat-facing or damage should be removed from the tree. These affected peaches should be discarded so the larvae inside do not have a chance to emerge.
If you have positively identified plum curculio in your orchard, begin control by using integrated pest management (IPM) techniques. IPM uses a variety of non-chemical measures to combat the pest, while also employing chemical controls if conditions are severe enough. If using insecticide, treat with the recommended product at shuck split. Second and third applications should be made at ten- to fourteen-day intervals thereafter, concluding thirty days prior to estimated harvest.
For more information, check out these additional resources:
A: There are several reasons pecans don’t produce.
- Trees grown from seeds are slower to bear nuts. It may take 15 years.
- It could be a poor variety for pecan production.
- If you have clay soil, the tree will struggle. They prefer sandy loam.
- Your tree probably needs fertilizer. Inadequate zinc, nitrogen, and lime can limit production. Get a soil test so that you will know for certain what your soil needs (soiltesting.tamu.edu).
- Poor pollination is a common reason for the lack of nut production. Pecans produce both male catkins and female flowers on the same tree. However, frequently the catkin’s pollen is shed either too early or too late to pollinate the flower. Having more than one tree can help with this.
- Too much or too little water affects production.
- Disease and insect pests can seriously limit production. Look for a variety with good disease resistance. You can find a list here:
To read more, click on this link:
A: Not to start on a sour note, but limes are extremely cold-sensitive, more so than most other citrus trees. It might survive, depending on how much energy you have to tend it during the winter. Temperatures in the high twenties can kill or severely damage a lime tree. Last January Denton’s temperature dropped to 11 degrees three nights in a row, so you would have had to perform extreme measures to protect it.
The air temperature, the length of time it remains below freezing, and the leaf temperature (which may be colder than the ambient temperature depending on atmospheric conditions) are all factors in
whether your tree will survive any freeze.
If you decide to plant it outdoors, put it on the south or southeast side of the house to take advantage of the protection from the house itself, and plant it in full sun. Consider building a frame out of PVC pipe that you can cover with blankets or frost cloth and install heat lamps underneath. The safest idea, however, might be to put your pot on wheels and move it in and out of the garage just as you have done in the past.
Learn more about protecting citrus plants from freeze at this link:
A: Growing blueberries in North Texas is not easy, but it is possible if you understand their requirements. Blueberries are calcifuges, which simply means they cannot tolerate alkalinity. Most of Denton County has alkaline soil, and many of us also have alkaline and/or salty water. These are disadvantages that we have to workaround.
Look for a variety of Rabbiteye (Vaccimium ashei). You can try planting them in the ground, but prepare to be disappointed because you can not permanently change soil pH. For best results, grow them in a large container (like a whiskey barrel) in a soilless peat mix made for blueberries, and water with rainwater. Mulch them well with an acidic mulch such as pine bark, and be sure they receive 8-10 hours/day of sunlight. They are not drought tolerant, so do not let them dry out.
It takes about three years for a bush to become hardy, and they remain fairly weak until then. The links below will tell you all you need to succeed. Pay special attention to the advice regarding fertilization in the second article. And when you pick your first plump, delicious fruit, you can rightly call yourself a berry good gardener.
Learn more about growing blueberries at these links:
Blueberries for Texas – https://aggiehorticulture.tamu.edu/archives/parsons/publications/blueberries/blueberries.html
Blueberries – https://aggiehorticulture.tamu.edu/fruitnut/files/2015/04/blueberries_2015.pdf
A: Just in case your soil from last year has some residual pathogens, replacing it this year will get you started on the right foot. Your garden center may have many different types of soil for plants. Look for a product labeled potting mix as opposed to potting or garden soil. The University of Maryland Extension services tells us that good potting mixes, sometimes called soilless mixes, should be “lightweight, have a pH of about 6.2, and are typically comprised of ingredients such as sphagnum peat moss, perlite, vermiculite, composted bark, compost, and coconut coir.”
Before you add the new soil mix into the container, clean it thoroughly. Large containers are more challenging to clean than smaller pots that you can soak. You can clean your container using a solution of one part sterilizing liquid such as bleach, hydrogen peroxide, or vinegar to nine parts of water. Scrub the inside of the pot, then rinse thoroughly and let dry completely.
Fill your containers with the new potting mix to about 1-2 inches from the top. Water the potting mix before adding plants. It also helps to let the new plants sit in some water before adding them to the pot to dampen their root mass. “Plant individual plants so roots are set shallowly rather than deeply and gently firm soil around the roots. Finally, water the plants in thoroughly.” (Gardening in Containers, https://extension.uga.edu/publications/detail.html?number=C787&title=Gardening%20in%20Containers#Planting).
Fertilize the plants about three weeks after planting. You can choose a foliar fertilizer, a soluble fertilizer, or one that has an extended-release. Follow the instructions on the package for quantity and frequency for the type of fertilizer you chose.
What can go wrong?
After getting your plants off to a good start, what should you do if there seems to be a problem? First, and most important, is diagnosing what is interfering with the plant’s growth. Is it a pest, a nutritional deficiency, or a disease? Studying the plant’s leaves and stems may give you the answer.
Each insect species prefers to feed on and live in a particular plant part or parts. Learning an insect’s favored locations greatly increases the ability to control the population. Common insect problems on container plants in North Texas include aphids, spider mites, thrips, and gnats. A comprehensive article from the North Carolina State Extension Service describes each of these culprits and common container plant diseases in the section on Integrated Pest Management. (“Plants Grown in Containers” https://content.ces.ncsu.edu/extension-gardener-handbook/18-plants-grown-in-containers.)
Even with good fertilization practices, plants in containers may develop nutritional deficiencies. Your fertilizer usually contains nitrogen, potassium, and phosphorous. However, it may not contain other required macro and micronutrients. The references below provide a description of the impact of each of these deficiencies on container-grown plants. The photos in the first reference from the University of Georgia are especially helpful when trying to diagnose your plant’s problems.
“Container Nursery Crop Nutrient Deficiencies–A Photo Library” from the University of Georgia http://www.canr.org/pastprojects/1999012.pdf
“Diagnosing Nutritional Deficiencies” https://aggie-horticulture.tamu.edu/ornamental/greenhouse-management/diagnosing-nutritional-deficiencies/
“Guide to Symptoms of Plant Nutrient Deficiencies” https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1106.pdf
A: The materials used for the containers we grow plants in is important. Without careful consideration, all the benefits of growing vegetables can be undone, or worse, by using unsafe materials for raised beds.
There are many advantages to using galvanized steel containers for growing plants. They come in a variety of sizes and don’t require assembly. Their standing height may make it easier to tend to the plants. Galvanization is a process that applies a zinc coating on steel to resist oxidation prevent rust and corrosion.
Safety of Galvanized Steel
Generally speaking, using galvanized steel containers for growing vegetables is safe. That said, if you’re using a salvaged galvanized container, it is critical to know the history of the container’s use. Do
not use it to grow edibles if used for holding herbicides, pesticides, or fungicides. If the container was used to store petroleum products, it should not be used to grow edibles. All of these considerations apply to using galvanized corrugated metal for building raised beds.
Other Raised Bed Materials
Other materials commonly used to construct raised beds include wood, cement blocks, synthetic plastic, and composite wood products.
Let’s address using lumber for raised beds first. Because the wood is in contact with soil and water, it’s important to use naturally decay-resistant or treated wood to build the bed. Decay-resistant types of wood include cedar, black cherry, oak (bur, chestnut, post, white), black locust, Osage orange, or redwood. (Source: USDA Forest Products Lab). Many types of chemical treatments are applied to wood to prevent insect attacks and fungal diseases. Many of these treatments, particularly in salvaged wood, are not safe in raised beds for growing edibles.
Toxic Chemical Wood Treatments
Chromated Copper Arsenate (CCA) was the primary treatment for wood material from 1970 to the early 2000s. Studies found that CCA-treated wood should not be used for raised beds because rainfall and solar radiation increased arsenic leaching from the wood. Fortunately, CCA-treated wood is no longer on the market.
Creosote is a patented wood preservative. It is a mixture of 200-400 different compounds. It is a restricted pesticide primarily to treat railroad cross ties, utility poles, marine structures, and some bridge timbers. It has an objectionable odor and oily texture that can ruin apparel and footwear and cause sun sensitivity to exposed skin. And it may be carcinogenic. It is not permitted for interior use and should not be used if it will contact food, feed, or drinking water.
Pentachlorophenol (Penta) was developed in the 1930s and is now a restricted use pesticide with no interior use. It is an oil-based preservative used on utility poles, fence posts, bridge timbers, foundation piling, and glue-laminated timbers. Penta is a potent biocide (a substance that destroys living things) that can cause skin irrigation, plant damage, or plant death. Penta-treated wood should not be used for raised bed construction.
Safe Wood Preservation Methods
According to the University of Maryland Extension, there are several safe methods for preparing lumber to limit the damage caused by insects or fungus.
- Paint the wood with exterior latex paint to minimize soil contact with treated wood (Source: Oregon State Extension)
- Treat the wood with a semi-transparent oil-based stain (Source: USDA Forest Products Lab)
- Apply a heavy plastic liner between the treated wood frame and your garden soil, allowing for soil drainage (Source: Iowa State University, Mass. Dept. of Environmental Protection)
Alkaline Copper Quaternary (ACQ) treated wood has been available since the 1990s and is the most widely used preservative for residential applications today. ACQ does not contain arsenic but does contain copper. It is considered to have relatively low risks and is essentially non-toxic with normal skin or oral exposures. Learn more about the health risks associated with ACQ-treated wood on the National Pesticide Information ACQ Information page: http://npic.orst.edu/ingred/ptype/treatwood/acq.html.
Cement Blocks and Poured Concrete
Masonry products are long-lasting but more expensive than wood for constructing raised beds. Cement, cinder, and concrete blocks are made with cement mixed with sand or small rocks. Fly ash, a by-product of burning coal, is often used to produce these blocks. Fly ash contains heavy metals and other hazardous materials. Typically, the product labels for these blocks do not list the types of aggregate used in their manufacture. The blocks can be sealed with polymer paint to reduce the risk of leaching the toxins into the soil.
Poured concrete is another long-lasting (and more expensive) option for building raised beds. Verify that any curing compounds, stains, sealers, or release agents are safe in edible gardens.
Learn more about using safe building materials for raised beds below.
Sources and Resources
Growing Vegetables in Galvanized Containers.” University of California Cooperative Extension
“Toxicity Concerns about Raised Bed Materials.” Iowa State University Extension and Outreach
“The Safety of Materials Used for Building Raised Beds.” University of Maryland Extension
Building Raised Beds.” University of Florida Gardening Solutions
Texas A&M AgriLife Extension “Composting”: https://agrilifeextension.tamu.edu/…/gardening/composting/
A: Thank you for contacting the Denton County Master Gardener Help Desk with your question about treating your zoysiagrass for brown/large patch in October.
Brown patch, also known as Large patch, is a fungal disease (Rhizoctonia spp.) that is the most common and damaging disease of warm and cool-season grasses. Warm-season grasses most commonly affected are centipedegrass, zoysiagrass, and St. Augustinegrass. Bermudagrass is not as severely damaged. Its rapid growth allows Bermudagrass to recover more quickly. Brown/Large patch is most active in late fall in spring.
The symptoms appear as thin patches of light brown grass in rough circular shapes. Sometimes the center recovers, giving the diseased area a donut-shaped appearance.
To help you diagnose if your zoysiagrass is suffering from brown/large patch disease, look for yellow leaves at the edges of the patches. The leaf sheath will rot so that the leaf blade will separate easily from the runner with a gentle tug. For a specific diagnosis, send a sample to the Texas Plant Disease Diagnostic Lab using the form found at this link: https://plantclinic.tamu.edu/files/2010/10/Plant-Disease-Diagnosis-Form-D-1178.pdf.
Prevention & Control
The disease develops more in the following conditions:
- Applying fertilizer in late fall
- Poor drainage
- Watering too frequently
- Mowing lower than 2” to 3” high
- Heavy thatch
Brown/large patch is difficult to get rid of, so preventing the disease is critical. The first step to preventing brown patch is to eliminate any of the conditions that promote the development of the disease:
- Improve drainage in areas where the soil stays wet. A thin top dressing of compost applied in early spring will help drainage. If the soil is bare, amend it with 3″ of expanded shale and turn or till it in 6″ to 8″. Apply 3″ of compost on top. Redirect downspouts and check irrigation system zone settings to avoid overwatering poorly drained areas.
- Aerate the soil to decrease thatch.
- Water in the early morning to allow the leaf blades to dry during the day. And water only when needed.
- Avoid applying high nitrogen fertilizer in mid-to-late fall or early spring before the lawn fully greens up. Have your soil tested and apply fertilizer according to the recommendations. Click this link for step-by-step directions for having a soil test done: https://dcmga.com/north-texas-gardening/community-gardening/soil-testing/.
- Mow in the morning, after the dew has dried, and set the mower blade height to 2” to 3”. Avoid spreading the disease to other areas. In warm, moist weather, remove the clippings and mow the diseased areas last.
Fungicide treatments of warm-season grasses in the fall are crucial for best disease control. The first application should be made in October and repeated 2 to 4 weeks later. Reapply in April. Fungicides with these active ingredients are most effective: Azoxystrobin (with Propiconazole), Pyraclobstrobin (with Triticonazole), or Fluoxastrobin.
As always, carefully read and follow the cautions and instructions on the product label.
Your zoysiagrass may recover from a light brown patch infection as temperatures rise in the late spring or early summer. Resodding extensively damaged areas may be needed in the spring.
Learn more about brown/large patch at these web links:
“How to Diagnose and Manage Large Patch Disease in Warm-Season Turfgrass”, Texas A&M AgriLife, https://cdn-ext.agnet.tamu.edu/wp-content/uploads/2018/10/E-633-how-to-diagnose-and-manage-large-patch-disease-in-warm-season-turfgrass.pdf
“Brown Patch Disease of Lawns – Introduction”, Texas A&M AgriLife Extension Education in Bexar County, https://bexar-tx.tamu.edu/homehort/archives-of-weekly-articles-davids-plant-of-the-week/brown-patch-disease-of-lawns-introduction/
“Brown Patch & Large Patch Diseases of Lawns”, Clemson Cooperative Extension
A: Thank you for contacting the Denton County Master Gardener Help Desk. Overseeding Bermudagrass is not difficult. Timing and preparation are important steps to ensure a good rate of germination. Here are the important steps and timing for our area:
Step 1 – February / March
Apply a pre-emergence herbicide for crabgrass, goosegrass, and other summer annual weeds. Timing of this step is critical and must be done when the soil temperature is cool and the summer annual weed seeds have not yet germinated.
Apply a post-emergence herbicide on cool-season weeds that are already growing in your lawn. Be careful to avoid overspray onto landscape plants you care about.
Request a soil analysis to help you understand what nutrients are needed for a healthy lawn. More information and the steps for requesting a soil analysis can be found at this link on the Denton County Master Gardener website: https://dcmga.com/north-texas-gardening/community-gardening/soil-testing/
Step 2 – April
Prepare the seedbed where you plan to overseed. First, dethatch the existing lawn with a vertical mower. Then aerate the soil, and, lastly top-dress with sandy loam. Vertical mowers and aeration devices can be rented for use.
Following the recommendations from your soil analysis, apply a starter-type fertilizer with an NPK ratio of about 1:2:1 (Nitrogen-Phosphorus-Potassium). Irrigate to settle the soil.
Step 3 – April / May
No earlier than April, or when the temperatures are consistently over 70 degrees F, overseed your lawn with a good quality Bermudagrass seed suitable for this area. Lightly rake the top-dressed soil to create ridges. This article from Texas A&M AgriLife will help you choose a suitable Bermudagrass variety, weblink: https://foragefax.tamu.edu/files/2013/05/E320.pdf
Thoroughly soak the soil, but not to the point of run-off. Water daily until the seeds germinate. Water less frequently, but thoroughly, after the seeds germinate.
Step 4 – Maintenance
Mow after the seedlings reach 2 to 3”, setting the mower blade height to 1 ½ to 2”. Sharpen your mower blades to avoid pulling up or damaging the seedlings. Apply a high-nitrogen fertilizer after mowing 2 to 3 times, usually not until late May / early June. It’s best to hand-dig weeds rather than using herbicides to avoid damaging the young seedlings. Water your lawn 1” weekly, absent rainfall, during the hot summer months. Apply a pre-emergence herbicide in September to suppress cool-season weeds, and again in late winter to suppress warm-season weeds.
This article from Texas A&M AgriLife has excellent step-by-step instructions for preparing the planting area and broadcasting seed, weblink: https://agrilifeextension.tamu.edu/library/landscaping/turfgrass-establishment-for-texas/.
Refer to this article from Texas A&M AgriLife for guidance on fertilizing warm-season turfgrasses in Texas, weblink: https://agrilifeextension.tamu.edu/library/landscaping/lawn-fertilization-for-texas-warm-season-grasses/.
Lastly, this article from Texas A&M AgriLife has a wonderful Bermudagrass home lawn management calendar that should help you know when to take which actions, weblink: https://agrilifeextension.tamu.edu/library/landscaping/bermudagrass-home-lawn-management-calendar/.
A: Core aeration involves removing plugs of soil from a landscape troubled by heavy, clay soil and/or compaction from foot traffic or construction. Turf needs oxygen as much as it needs water, so periodic core aeration advances the absorption of both elements. Topdressing with compost afterward further improves soil by adding microbes and nutrients to grow healthy roots, to discourage suffocating thatch, and improve water infiltration.
To determine if your lawn would benefit from aeration, do a screwdriver test. Probe the suspect areas with a screwdriver; if you can’t easily penetrate the earth, you’ve got compacted soil, and aeration will be beneficial.
Texas A&M recommends twice yearly core aeration of the most compacted areas of your lawn. This task should be done in the cool of the day during times of active turf growth, not during dormancy. (March and October) Soil needs to be somewhat moist for best results; waiting for 24-hours after irrigation or significant rain should be sufficient. In contrast, do not aerate immediately after watering, otherwise, you can actually make the compaction worse.
For small areas, inexpensive manual aerators will do. For an entire lawn, consider renting a core aerator from a lawn and garden center or hiring a professional. Make sure to flag sprinkler heads so you don’t damage your irrigation system.
Immediately topdressing with ½” of fine compost and watering it in will allow the compost to filter down into the cores and get to work. The soil cores unearthed in the process can be allowed to disintegrate naturally, or if they are unsightly to you, simply rake them up.
Refer to these links for detailed information:
Excellent, brief publication on good turf management: https://aggieturf.tamu.edu/wp-content
Watch 27:00 to 30:00 in this video presentation given by Texas A&M Agrilife Extension horticulturalist David Rodriguez: https://youtu.be/tp6v5RzyzjM
𝗛𝗼𝗿𝘀𝗲𝗵𝗲𝗿𝗯: 𝘊𝘢𝘭𝘺𝘱𝘵𝘰𝘤𝘢𝘳𝘱𝘶𝘴 𝘷𝘪𝘢𝘭𝘪𝘴 (sometimes called straggler daisy). According to the Native Plant Society of Texas, “horseherb is native to south and south-central Texas and adapts to most other parts of the state. It can grow up to 8-10 inches tall, with opposite leaves that are usually less than 1 inch long. It has a sprawling to prostrate habit. Horseherb is perennial and although deciduous, it may remain green during a mild North Texas winter”. Not everyone loves this plant as it can spread somewhat aggressively. More information on the care of horseherb: https://npsot.org/wp/story/2018/10777/…
Welcoming pollinators to your yard (with native plants): https://www.youtube.com/watch?v=DjXtQFhhR9w
A: Spring warmth awakens our garden favorites, but it also coaxes to life the undesirables, like poison ivy. The chameleon of vines, PI varies greatly in its appearance, confounding our efforts to identify and avoid it.
Read on to learn the differentiating characteristics and control measures. The links, below, allow for further research. There’s even a fun quiz to help you practice PI identification. This author got 53 correct out of 55. Who can beat that score? Comment below!
Virginia creeper – Each compound leaf consists of UP TO five leaflets. In early growth, VC may only
show 3 leaflets, with more leaflets appearing over time.
PI – Center leaflet has a longer stalk than the side leaflets, which seem to have almost no stalk at all and are always directly opposite each other.
VC – Individual leaflets radiate uniformly from the center with virtually equal stalk lengths.
PI – Has no tendrils or adhesive discs, but uses aerial roots to climb structures.
VC – Uses tendrils and adhesive discs to climb structures.
PI – Older vines have a demonstrable hairy appearance due to the aerial roots. Evidence of old, hairy vines wrapped around a tree, for example, will signal that PI was or is present in the area. These old vines contain the same irritating chemical as the rest of the plant.
PI – Off-white berries in clusters form in spring and remain all winter.
VC – Greenish spring blooms produce berries that ripen to a black or dark blue in the late fall.
PI – Leaf margin appearance varies greatly.
VC – Leaf margins are serrated.
Poison ivy, especially when immature, can be pulled—or “grubbed”—when the soil is moist. To protect your skin, wear gloves, a long-sleeved shirt, and long pants tucked into socks. Place a plastic bag over your hand and forearm; then, grab pliers with your “bagged” hand and pull up the vine from ground level (you want as much of the roots as you can get). The bag can be inverted over the vine for disposal. Your pliers will have to be washed after grubbing, as the PI skin irritant can be transferred from the tool to you. Your clothes must be carefully removed and washed, for the same reason.
An effective chemical method of control involves cutting the PI vine and immediately brushing the open cut with an herbicide labeled for PI. A dishwashing wand-type applicator with a sponge tip is a great tool for this job. (Reserve this sponge for herbicide use only.) Use an empty can to carry a small amount of herbicide and the sponge-wand as you go about searching for these persistent vines. Dispose of remaining herbicides as recommended on the product label. Sponge application is safer than spraying since you won’t need to worry about overspray reaching desirable plants. Always wear the personal protective equipment as directed on the herbicide label and follow all usage instructions.
You may have to treat it repeatedly to control PI, but it can be managed.
Remember to take the PI quiz so you will be better able to outwit that wily, garden chameleon!
Poison ivy identifying quiz (fun AND educational): https://www.birdandmoon.com/poisonivy/
Poison ivy control: https://aggie-horticulture.tamu.edu/travis
Distinguishing between poison ivy and Virginia creeper: https://extension.umd.edu
Great article on distinguishing between poison ivy and look-alikes https://www.canr.msu.edu/news
Helpful article describing Virginia creeper http://sfrc.ufl.edu/extension
Using pliers-and-bag method to pull PI: https://aggie-horticulture.tamu.edu/newsletters
A: We’ve had an unusually wet August in North Texas this year. Imported and native fire ants are often more visible in the landscape after it rains. The first step is accurately determining that you’re dealing with imported fire ants. Then, follow the Two-Step Fire Ant Control Method to manage the fire ants in your landscape.
Imported Red Fire Ant Identification
There are hundreds of species of ants in North Texas, and most are not harmful. Most ants are beneficial insects because they prey on other insects and effectively aerate more soil than earthworms. Accurately identifying the species of ant will ensure that the control measures taken are effective. There are four native fire ant species in Texas, and the fifth species is the imported red fire ant. The native fire ant species are not as aggressive as the imported red fire ant. (Cook et al.)
- They are aggressive and run up any object placed into their nest and try to bite and sting it.
- They have a narrow “waist” between the thorax and abdomen with a petiole and a postpetiole.
- Their antennae are jointed like an elbow.
- Other physical characteristics unique to the imported red fire ant are more challenging to see without a microscope. They include a median clypeal tooth, a striated mesepimeron, the antennal scape nearly reaches the vertex, the postpetiole is constricted at the back half, and the petiolar process is small or absent. (See the illustration in the “Key to Common Pest Ants and Fire Ant Species” listed Resources.)
Fire Ant Swarms
Fire ants will swarm after it rains, particularly following a dry period as we had in July. Swarming is how fire ants reproduce and expand their range. You may see winged male and female ants exiting the mound. They mate in the air while flying. The male ant dies, the female ant falls to the ground, burrows into the ground, and lays eggs to start a new colony. Swarming fire ants can be confused with termite swarmers. Along with the physical characteristics listed above, the fire ant’s front wings are longer than the back wings. (Hu)
Fire ant swarmers are attracted to reflective, shiny surfaces. You may spot them in swimming pools, ponds, or water features. Float a tennis ball or two in the water for the ants to climb onto (they’re not good swimmers). Collect the tennis balls and drop them into a plastic bag, tie off or seal, then discard. (Hu)
Two Steps to Control Fire Ants
Eradication or total elimination of fire ants is not possible or practical. However, following these steps recommended by Texas A&M AgriLife Extension and many other state extension services will effectively control fire ants in the landscape.
Step 1 – Apply Fire Ant Bait
Applying a fire ant bait product twice annually is an effective and cost-efficient method of controlling fire ants. The ants do the work for you, gathering the bait and taking it back to the colony, which is ingested by the worker ants and queen, effectively killing the entire colony. Fire ants forage up to 300 feet from their mounds, so broadcasting bait is effective and doesn’t require knowing where the mounds are.
Fire ant baits are typically in granular form. Their low toxicity and low application rate make them one of the safest control methods for homeowners to use. They are best used as a broadcast, using a hand-held spreader. Set the hand-held spreader with a narrow opening to distribute 1 to 1.5 lbs per acre. Drop spreaders typically cannot be set with a narrow enough “gate” opening to broadcast the small amount needed.
Tips for Using Fire Ant Bait Effectively (Bertagnolli).
- Apply fire ant bait twice annually, once in spring (May/early June) and again in fall (late September/October).
- Baits work best when fire ants are actively foraging for food. To find out if they’re foraging, drop a few greasy potato chips several places in the landscape. After 20 to 30 minutes, check the potato chips for fire ants. If they’re on the chips, they’re foraging, and it’s a good time to broadcast fire ant bait.
- Use fresh bait; purchase just enough to treat one season. Fire ant bait uses soybean oil as an attractant. Soybean oil can become rancid quickly and will no longer be attractive to the ants.
- Apply the bait when it’s dry, at least 4 hours before expected rain. Wait to apply until the morning dew has dried. Do not water in the pesticide and turn off irrigation.
- Broadcast the bait around the perimeter of the home, in the garden, and compost pile.
Step 2 – Spot Treat Individual Mounds
Spot-treat individual mounds or colonies in high traffic areas, which may be more visible after rain. (Schattenberg) Many labeled products for non-bait fire ant control are available in dust, liquid concentrates or drenches, or granular forms. These treatments will usually kill the colony in 1 to 2 days.
The Final Word
Following these steps, with the appropriately labeled products and at the right time, really work. Home DIY remedies such as sprinkling grits over the mound do not work, and some DIY methods can be dangerous (e.g., gasoline or other petroleum products). Always carefully read the product label for application instructions, safety precautions, and proper disposal.
Sources and Resources
Bertagnolli, Vicky. “Hints and Tips for an Effective Fire Ant Management Program in Home Landscapes Using Broadcast Baits.” Clemson Cooperative Extension Home & Garden Information Center, 2020, https://hgic.clemson.edu/factsheet/hints-and-tips-for-an-effective-fire-ant-management-program-in-home-landscapes-using-broadcast-baits/. Accessed 09/05/ 2021.
Cook, Jerry L., et al. “Key to Common Pest Ants and Fire Ant Species.” Texas A&M AgriLife Extension, 2014, http://fireant.tamu.edu/files/2014/03/ENTO_001.pdf. Accessed 09/05/ 2021.
Hu, Xing Ping. “Swarming Fire Ants.” Alabama A&M and Auburn Universities Extension, Alabama Cooperative Extension System, 2021, https://www.aces.edu/blog/topics/lawn-garden/swarming-fire-ants/. Accessed 09/05/ 2021.
Schattenberg, Paul. “Spring is the time for Texans to ‘two-step’ toward fire ant control.” AgriLife Today, 2020, https://agrilifetoday.tamu.edu/2020/05/13/spring-is-the-time-for-texans-to-two-step-toward-fire-ant-control/. Accessed 09/05/ 2021.
A: Weather conditions in North Texas this spring and summer have created the ideal conditions for armyworms – dry conditions, followed by a cool front and rain event.
What are Armyworms?
There are several species of armyworms found in Texas. The fall armyworm Spodoptera frugiperda causes the most problems in home landscapes and golf courses. Other species include the yellow striped armyworm Spodoptera ornithogalli, the beet armyworm Spodoptera exigua, and the true armyworm Mythimna (=Pseudaletia) unipuncta.
The fall armyworm is the progeny of the fall armyworm moth, which has a wingspan of about 1.5 inches, with white hind wings and dark gray mottled front wings. The female moth lays tiny whitish eggs at the base of the host plant. The larvae that hatch from these eggs are what you see. They are green with brown or black colorations and a distinct inverted V shape on their head. They are 1 to 1.5 inches at maturity. Four to five generations move through the state during the growing season. They are always there but are too small to see. With the right weather conditions, their population can explode in just a few days.
Armyworms prefer to feed on high-quality fertilized forage (ex. hay, Bermudagrass, sorghum, corn, wheat). However, when food sources are scarce, they will feed on other plants such as sweet potatoes, beans, turnip, clover, tobacco, spinach, cucumber, potatoes, tomatoes, cowpeas, cabbage, etc.
They feed on the blades of turfgrasses but do not eat the roots. In many cases, turfgrasses, especially Bermudagrass, will recover from a light infestation. Heavy infestations that cause significant damage can cause plant death.
Active feeding occurs in the early morning and late afternoon/early evening. However, armyworms can be feeding all day.
Natural predators of fall armyworms include birds, paper wasps, fire ants, ground beetles, skunks, and other rodents. Spotting congregations of birds feeding in turfgrass is a sign that fall armyworms are there.
Apply chemical treatments only when armyworms occur in large numbers (5 or more per square foot) or excessive plant damage. In pastures, hayfields use products labeled from armyworms (ex. Pyrethroids and growth inhibitors). Pyrethroids will kill the armyworms; growth inhibitors disrupt the normal development of immature insects.
In-home landscapes, these steps are recommended if treatment is warranted [Alabama Cooperative Extension System]:
- Mow first if mowing is needed
- Lightly irrigate the area several hours before treatment to bring larval activity to the surface.
- Apply insecticide early or late in the day
- Insecticides for home use include granular pyrethroids (ex. bifenthrin), effective low impact insecticides such as halofenozide (small caterpillars only), and spinosad. One application will usually solve the problem; heavy infestations may require a second application after 2 – 3 days. Bacillus thuringiensis (Bt) selectively controls small larvae but is effective for only 1 – 2 days. Always carefully read and follow all label instructions and restrictions. This article on managing armyworms in turfgrass from Alabama Cooperative Extension System includes a list of insecticides for home use, weblink: https://www.aces.edu/blog/topics/lawn-garden/controlling-fall-armyworms-on-lawns-and-turf/?cn-reloaded=1
Learn more about fall armyworms at these websites:
“Fall Armyworms On The March Across Texas” (July 22, 2021). Adam Russell, Texas A&M Communications. https://today.tamu.edu/2021/07/22/fall-armyworms-on-the-march-across-texas/
“Controlling Fall Armyworms on Lawns and Turf” (March 24, 2021). Katelyn Kesheimer, David Held and Patricia Cobb, Alabama Cooperative Extension System https://www.aces.edu/blog/topics/lawn-garden/controlling-fall-armyworms-on-lawns-and-turf/?cn-reloaded=1
“The Fall Armyworm – A Pest of Pasture and Hay.” (2019 Revision). Allen Knutson, Texas A&M AgriLife Extension https://foragefax.tamu.edu/files/2019/07/Armyworm-Fact-Sheet-2019.pdf
“Armyworms in Turfgrass” (October 2018). Chris Sansone, Rick Minzemayer, Mike Merchant, Texas A&M AgriLife Extension: https://citybugs.tamu.edu/factsheets/landscape/lawns/ent-1007/
A: Bagworms have claimed your trees as their home. And their nursery. And their all-you-can-eat buffet. Fortunately, both Integrated Pest Management (IPM) and chemical controls are effective this time of year.
Usually, the first sign of an infestation is the distinctive, oblong “bags,” encrusted with plant debris, hanging from stems. The bags hold hundreds of eggs, which overwinter from the previous fall. Sometime between April and June, tiny larvae emerge, spin a single silk thread, and attach themselves to nearby leaves where they begin feeding. The caterpillars use their silk and your plant debris to weave the case, which they carry and live in throughout the season, enlarging it to accommodate their growth.
Male bagworms complete development as small moths, which emerge from the bags ready to mate. The female adult’s final stage is more maggot-like, without functional eyes, legs, or antennae. She protrudes halfway out of her case and exudes pheromones to attract a mate. Once mated, she deposits her eggs into the case and dies. The eggs remain sheltered in the case until they hatch in spring when the cycle begins anew.
To control the infestation, hand-pick all cases from the tree AND the ground; bag and discard. If your tree is large or infestation is severe, consider recommended chemical controls, even using a professional service for large trees. Timing insecticide usage to caterpillar lifecycle is critical. An insecticide is ONLY effective when bagworms are actively feeding in the larval or caterpillar stage. April
to August is your insecticide window, but any chemical control can impact beneficial organisms, so use it as a last resort.
Recommended insecticides for early-season use include Bacillus thuringiensis, spinosad, and any of the pyrethroid insecticides. Infestations noticed in late summer will require pyrethroid sprays for
effective control. Before purchasing any insecticide, read the label fully to make sure the product is suitable for bagworms. Purchase any recommended personal protective equipment (PPE) you do not
already own. Getting home without PPE may tempt you to use the product without the proper protection, and that is a risky action with any chemical.
Refer to the links below for detailed information from Texas A&M entomologists:
A: Just like any tool in our garden shed, rain barrels need their own regular maintenance. Contaminants like roof debris, algae, and mosquito larvae can create problems, but there are ways to refresh our barrels, inside and out. If the water is clear, even if you haven’t used it all winter, it is ok to use.
Drain the barrel, using the water where you can in your yard. Once empty, clean its exterior and then lightly sand and paint it black to prevent algae growth. Replace the mesh screening, if necessary, to keep mosquitoes out. Repaint with a color complementary to your home and stencil pretty designs or garden motifs. You can even use wood slats to surround the sides and top of your barrel.
Clemson University’s document, “Rainwater Harvesting for Homeowners” details steps to clean and refurbish an older rain barrel. Refer to pages 16, 19, and 20 for that information. Skip over other portions of the document that pertain to South Carolina.
In the video below, Daniel Cunningham, Horticulturalist, describes creative ways to improve the curb appeal of your barrel.
It shouldn’t take much effort to restore your “old friend” to its former self, and you’ll again enjoy its beauty while tending your garden.
A: North Texas’ often extremely hot summers can be hard on many plants. Knowing when and how much to irrigate grass, trees, vegetable garden, and flower beds can help. Don’t forget to add mulch to retain moisture and moderate the temperature of the soil. AgriLife offers this advice on the most effective ways to add supplemental water.
Some plants are better able to take the heat than others. After our last terrible drought year in 2011, we surveyed our members to find out what thrived, what survived, and what died. You might want to look at that list for future planting.
A: January in North Texas brings shorter daylight hours, cold weather, and irregular rainfall. All is not lost, some plants need to be planted this time of year in North Texas!
What to Plant in January
- Check out the Texas Superstar® Plants which are tested and selected for superstar performance in Texas at this link: https://texassuperstar.com/index.html
- Plan your new landscape considering the soil type, light conditions, and irrigation plans. Layout your design on paper including the existing plants.
- Browse plant and seed catalogs and order seeds now for spring flowers so early transplants can be started.
- Have your soil tested before establishing a garden or applying amendments. Texas A&M University’s Soil Testing Laboratory offers affordable, reliable analysis. The lab website is http://soiltesting.tamu.edu/
- Here is the link to the soil testing form, which includes instructions for collecting samples: http://soiltesting.tamu.edu/files/urbansoil.pdf
- Clean, sharpen and repair garden and lawn tools. Learn more tips and tricks for taking care of your tools at this link on the DCMGA website: https://dcmga.com/…/how-to-care-for-your-gardening-tools/
- Explore the Denton County Master Gardener Association website (https://dcmga.com/) to read many helpful articles on gardening throughout the year as well as details of upcoming events: https://dcmga.com/upcomingevents/
Sources and Resources
A: Of course! One of our favorite sites for natives is the Lady Bird Johnson Wildflower Center. You can input your criteria for a list specific to our area. Another great site, which includes native
and adapted plants is Texas Smartscape.
The Native Plant Society of Texas-Trinity Forks Chapter also offers comprehensive lists of Texas natives for Denton County’s particular eco-region. And, our annual plant sale is a great place to find the native and adapted plants on your wish list. This year, it’s May 4th at Trinity United Methodist Church (633 Hobson Lane, Denton) from 9 am to 2 pm (or until sellout). The plants find new homes quickly, so come early for the best selection.
Learn more about native and adaptive plants at these links:
A: These are frequent questions. As a volunteer organization, we, unfortunately, do not have the resources to make home visits. But there are various ways we can educate you to help yourself.
- We can help you identify plants if you send pictures to our Help Desk.
- We can send you lists of plants appropriate for Denton County.
- We can refer you to our member Gardenscapers team.
- You can research our online inventory of North Texas Gardening articles, information, and presentations.
- You can sign up for our Design Your Yard class series.
- You can visit the educational booths at our free Fall Garden Festival on October 13th at Denton County Fairgrounds.
- You can grow with us! We’re currently accepting applications for our 2019 Intern Class, which happens to coincide with our 30th-anniversary celebration.
Our website, dcmga.com, has details and signups for all of our upcoming events.
A: When choosing any plant for your landscape, there are several factors to take into consideration. For shrubs, we’ll break those factors down into 3 categories: The purpose or function, the aesthetic considerations, and site conditions.
Shrubs in the landscape can serve several purposes or functions. As you think about the shrub selection, determine what you want the shrub to “do” in your landscape. Are you looking for a
- Fence or boundary formed by closely growing bushes or shrubs, also known as a hedge
- Focal point in the landscape
- Foundation planting to integrate the home into the landscape
- Screen for privacy or wind
- “Garden” room or a way to separate outdoor spaces from each other
- Defining a walkway
- Way to minimize drainage issues or erosion
The desired appearance and aesthetics of the shrub selection are also important. These include:
- The growth habit, i.e., is the mature shape pyramidal, columnar, spreading, . . .
- Does the shrub bloom, in what season, and what color?
- What does the foliage look like: color, texture, and shape? And, does the foliage color change by season?
- Is the plant’s appearance interesting in winter, e.g., bark, twig/branch structure, fruit, or berries?
- Does the plant offer benefits to wildlife such as food or shelter?
And, most importantly, the planting site conditions to keep in mind when selecting shrubs for your landscape:
- What is the sun exposure – full sun (6 – 8 hours), part sun (afternoon sun), part shade (morning sun), deep shade (dappled or very little sun)?
- What are the moisture conditions – is the soil perpetually moist or mostly dry?
- Is the plant site exposed to wind and temperature extremes?
- What type of soil is in the planting site, i.e., clay, sandy loam, sand, etc.
- What is the hardiness zone? North Texas is in zones 8a and 8b.
- Are there other plants in the space that will compete for water and nutrients?
- Are there below-ground obstructions such as pipes, electrical lines, tree roots?
- Are there overhead obstructions such as electrical or telephone lines?
Once you’ve thought through and determined the plant’s desired purpose and appearance, and most of the site conditions, have a test done on the soil from the planting site. It will provide you with a detailed analysis of your soil and recommendations for how to improve the soil fertility. This link on the Denton County Master Gardener Association website will tell you more about soil testing and the steps to having one done: https://dcmga.com/north-texas-gardening/community-gardening/soil-testing/
Then, check out these websites to help you make the right shrub choice for the purpose, desired appearance and planting site in your landscape:
“Outstanding Shrubs for Texas”, Texas A&M AgriLife Extension
“Texas Superstar® Plants”, Texas AgriLife Research
“Top 100 Plants for North Texas”, Texas A&M AgriLife Extension
Shop for shrubs at a reputable nursery or garden center. Check the plant’s overall appearance for health; pull the plant out of the container and look for roots that are light colored and firm; look for circling or girdling roots indicating the plant has been in the container for too long; and the trunk should be straight and branches should have no signs of injury. For more information on what to look for when selecting plants and shrubs go to this website:
“Selecting Trees and Shrubs”, Iowa State University Extension
Taking the time to consider all these factors will help you make a wise investment and add lasting beauty to your landscape.
A: You are so right! Using mulch in your landscape beds, around trees, and in vegetable gardens helps retain moisture, deter weeds, and moderate soil temperature. And, spring is the best time to add mulch.
The first decision you need to make is whether you want organic or inorganic mulch. Inorganic mulch, such as gravel, lava rocks or recycled tumbled glass, offers the advantage of being relatively permanent and suppresses weeds. Although it does less to retain moisture than organic mulch that is an advantage if your landscape is a xeriscape or filled with cacti and succulents.
In terms of using recycled tire rubber for mulch, Purdue University Extension Horticulture research found that “There are many questions remaining regarding the long-term safety of using recycled shredded or crumb rubber as mulch and playground surfaces. There’s little doubt that chemicals including heavy metals are released into the surrounding soil as the rubber decomposes. There are also issues with the rubber getting hot enough to burn tender plants.”
Which type of inorganic mulch you choose is primarily a matter of aesthetics.
Organic mulch comes from materials that were once alive and it decomposes over time. The mulch decomposition improves soil texture and provides nutrients to the plants. However, when the decaying mulch is integrated into the native soil, the decomposition process extracts nitrogen that needs to be replaced. Organic mulch needs to be reapplied or topped off every year. The types of organic mulch frequently used in North Central Texas landscapes include:
- Bark from pine, cedar, or redwood trees is the most common and readily available from nurseries and big box stores.
- Partially decomposed compost provides an excellent mulch but be aware that it may contain weed seeds.
- Leaves are readily available either from your fall leaf raking or from neighbors who set out bags of leaves for trash collection. Leaves work best if shredded before adding them as mulch.
- Pine Needles are a good mulch for acid-loving plants. They are slow to decompose and may pack if added in too deep a layer.
- Chipper debris includes a mixture of shredded bark, wood chips, and leaves from tree-trimming operations. Some tree trimming services will provide chipper debris to homeowners for landscape mulch at little or no cost. The City of Denton offers a low-cost mulch made from trimmings through their DynoDirt site (https://www.cityofdenton.com/181/Dyno-Dirt). You may pick it up or have it delivered.
- Grass clippings that are applied in thin layers that are allowed to dry between additions.
- Cotton burr mulch with a top layer of bark to keep in place
The deciding factors in selecting an organic mulch for most homeowners are cost, level of effort to make it ready and appearance.
How much to add?
3 to 4 inches is recommended. Here’s a mulch calculator to find out how much raw material you need for your landscape: Home Depot has an online calculator. You just specify the types of mulch, desired depth, and dimensions of your landscape to be covered. (https://mulch-calculator.homedepot.com/)
“Landscape mulch”: https://aggie-horticulture.tamu.edu/earthkind/files/2010/10/mulch.pdf
“Easy Gardening Mulching”: https://aggie-horticulture.tamu.edu/organic/files/2011/03/E-512_mulching.pdf
Mulching with Wood/Bark Chips, Grass Clippings, and Rock https://cesantaclara.ucanr.edu/files/238922.pdf
Mulching Garden Soils fact sheet https://extension.okstate.edu/fact-sheets/mulching-garden-soils.html
Pine Straw as a Ground Cover Mulch https://agrilifeextension.tamu.edu/library/landscaping/pine-straw-as-a-ground-cover-mulch/
Answer: That’s an excellent question! Sometimes it’s easy to tell if there are drainage issues in our landscape because of ponding water. However, understanding the drainage properties of your garden’s soil is best done with a simple soil percolation test. It’s also important to learn what nutrients your soil may need through soil analysis.
The soil is the source for all the elements plants need to grow: nutrients, organic matter, air, and water. Healthy soil is also the foundation of a water-efficient landscape, particularly in North Texas, where our soils are almost always poorly draining sticky clay. Soil that doesn’t drain well can cause your plants’ roots health problems such as root diseases, inability to take in nutrients, root system decay, and plant death. Soil that doesn’t hold water adequately also causes plant health issues from drought stress, possible salt build-up in the soil, and certainly requires more irrigation.
Soil texture describes the mix of the type of soil particle sizes – Clay (the smallest), silt (next largest), and sand (largest). Clay and silt soils have the highest water holding capacity, and sand has the lowest.
Denton County has three soil regions with these types of soil textures:
- Blackland Prairie – mostly dark black to light, grey clayey soils
- Eastern Cross Timbers – mostly sandy loam
- Grand Prairie – a mix of clayey, limestone, and silty loams
There may be multiple types of soil textures in your landscape.
Soil Percolation Test
- Shovel or spade
- Water and a bucket or container
- A watch or clock
- Dig a hole 6 to 8 inches wide and 2 feet deep. Tip: Be sure to know where the utility lines are before digging.
- Fill the hole full of water and make a note of the time.
- Put a yardstick in the hole every 15 minutes to measure the amount of water drained from the hole in inches. Make a note of the measurements.
- Fill the hole a second time and make a note of the time.
- Repeat Step 3 and note how long it takes for the water to drain again.
Interpret the Test Results
Looking at the amount of time it took for the hole to drain completely in steps 3 and 5:
Less than 15 minutes = Excessive drainage and poor water holding capacity
15 to 30 minutes = Adequate drainage and water holding capacity
30 minutes or more = Poor drainage and excess water holding capacity
Options to Improve Soil Drainage or Water Holding Capacity
Amendments can be added to your soil to improve how it handles water.
Excessive drainage/poor water holding capacity Add 3″ of finished compost and work it into the soil 6 to 10 inches with a garden fork or tiller. Finished compost has the color and texture of chocolate cake and doesn’t have any recognizable plant debris in it, such as sticks, twigs, or food particles. Apply a 3-inch layer of organic mulch (bark mulch, pine straw, etc.) in the root zone of the plants, leaving a 2-inch gap from the plant stem or trunk to hold moisture in.
Poor drainage/excess water holding capacity Add 3″ of finished compost or expanded shale and work it into the soil 6 to 10 inches. Shale is crushed and kiln-fired to make expanded shale. It holds 40% of its weight in water doesn’t break down like compost so that it can be added to the soil only once.
Adding 3 inches of finished compost to your soil, even when the soil’s drainage properties are good, always benefits the health of the soil and plants. Gently work the compost into the soil around the plants’ root zone 3 to 4 inches.
Get a Soil Test Done
Over time the quality of your soil changes. A soil test can identify nutrient deficiencies, acidity or alkalinity, amount of organic matter, and soil texture. Caring for your soil by identifying what is lacking and adding amendments is key to growing healthy plants year after year. Of course, the soil test cannot identify issues with the amount of sunlight, pests, or drainage issues in your garden.
Texas A&M AgriLife Extension Service Soil, Water, and Forage Testing Laboratory offers a soil testing service for a nominal fee. The lab sends the result to you (mail or email), including which nutrients are needed and how much to apply. Use this link to obtain the Urban and Homeowner soil test form, which includes instructions for collecting samples, payment, and mailing: http://soiltesting.tamu.edu/files/urbansoil.pdf. The forms and sample bags are also available at the Denton County office of Texas A&M AgriLife Extension Service.
Taking these steps to understand your soil’s drainage properties and the nutrients it needs will help you grow a healthy and beautiful garden.
Sources and Resources
“Improving Landscape Soils,” Texas A&M AgriLife Extension. https://aggie-horticulture.tamu.edu/earthkind/files/2010/10/soilimprovement.pdf
“Percolation Test,” University of Michigan, http://natureforcities.snre.umich.edu/wp-content/uploads/2009/nature_city/soils/getting_to_know_your_soil_exp3.pdf
“Soil Testing,” Denton County Master Gardener Association, https://dcmga.com/north-texas-gardening/community-gardening/soil-testing/
Answer: Absolutely! Fallen leaves that accumulate in our landscape are a terrific, free resource! Their benefits include conserving moisture, modifying the temperature of the soil, preventing soil erosion, reducing weed growth and when composted they supply a slow release of nutrients to plants.
Let’s talk about the various ways you can manage your fallen leaves with information from Texas A&M AgriLife Extension Earth-Kind Landscaping (click this link for more information: https://aggie-horticulture.tamu.edu/earthkind/landscape/leaf-management-plan/)
- You can mow a light covering of fallen leaves and leave them in place on your lawn. It’s helpful to use a mulching blade to shred the leaves into small pieces.
- Use the fallen leaves as mulch in your ornamental beds, vegetable gardens, and around trees and shrubs. Mowing over them and capturing them in your mower’s bag attachment will shred them and is an effective way to distribute them where you want. Apply 3” to 6” around trees and shrubs leaving a 4” to 6” gap around the plant’s trunk or stem. In ornamental and vegetable gardens apply 2” to 4”. Shredded leaves are also great used in garden paths.
- Shredded leaves can also be used to improve the soil. Work 6” to 8” of shredded leaves into clay soil to improve aeration and drainage. Doing this in sandy soil will improve water and nutrient retention in the soil. A light broadcast of high nitrogen fertilizer over the area and keeping the area moist will help decompose the shredded leaves.
- Dry leaves can also be composted along with other yard waste such as grass clippings, small shredded/chipped-up plants, and weeds. Leaves can also be decomposed by themselves into leaf mold that can be used as a soil amendment.
Leaf mold is super easy for homeowners to make and has lots of beneficial uses in your garden. Did you know that leaf mold holds 300% to 500% of its weight in moisture? In addition, when worked into the soil, it improves the soil structure and provides a habitat for good soil organisms like earthworms and beneficial bacteria. Leaf mold can also be used as mulch.
Leaf mold is produced through fungal decomposition which is cooler and slower than heat-generating composting. Here are some simple ways to make leaf mold:
- Rake the leaves into a pile, moisten them a little, and let them sit.
- Put the leaves into black plastic bags, wet them down and shake the bags to distribute the moisture, and poke a few holes in the bags. Put the bags in a shady spot and check them every few months to add water if needed.
- It speeds up the decomposition to shred the leaves and add a little high nitrogen fertilizer to the pile or bags. Turning the pile with a garden fork and turning over the bags also helps them decompose.
- Leaf mold is ready to use when it is soft and crumbly, resembling chocolate cake.
Learn more about leaf mold at these two links:
University of Wisconsin Extension: https://pepin.extension.wisc.edu/files/2017/08/170801-Leaf-Mold.pdf
University of California Cooperative Extension: http://ucce.ucdavis.edu/files/datastore/268-564.pdf
Regarding your question about whether using leaves as mulch will add phosphorus to your soil, according to the University of Massachusetts-Amherst “Heavy continuous use of compost, manures or other materials as a source of organic matter can lead to imbalances or excess levels of some nutrients after a number of years. As with any soil amendment, it is advisable to periodically test your soil for nutrient levels, pH, and organic matter and adjust your fertilizer and organic matter applications accordingly. “ (Article link: https://ag.umass.edu/cafe/fact-sheets/fertilizing-flower-gardens-avoid-too-much-phosphorus) Clink this link on the Denton County Master Gardeners Association website to learn more about why and how to have your soil tested: https://dcmga.com/north-texas-gardening/community-gardening/soil-testing/.
Thanks again for your terrific question and for being a good steward of our environment!
A: Here are some basic composting issues that you may need to address:
- Your mix may be too dry. It should be moist, not wet. Break down of components will not occur if the mix is dry.
- Your compost mix may not be ideal. As a rule of thumb, the carbon:nitrogen ratio should be 30:1. Food scraps and grass clippings are nitrogen sources. Carbon sources are paper, yard waste, tree leaves, and wood shavings.
- Your mix may benefit from adding store-bought compost activator, compost, or horse manure to kick start the process. This adds vital microorganism culture as well as nitrogen.
This article will give you an idea of how to estimate the carbon:nitrogen ratio:
A: Thank you for contacting the DCMGA Help Desk. What you see looks more like sunscald or sunburn than freeze damage. The damage is not repairable but is preventable. Here’s some information about what causes sunscald or sunburn in trees and how to prevent it.
What is sunscald or sunburn in trees? Sunscald or sunburn in trees is the death of the tree’s cambium tissue (living cells just under the bark) on the trunk due to high or rapidly fluctuating temperatures. There are two times of the year this can happen – winter and summer. Although not a common occurrence in Texas, sunscald in winter is caused by rapid fluctuations in temperature. The cambium tissue on the south or southwest side of the tree’s trunk warms from the sun’s heat then rapidly refreezes, likely during overnight freezing temperatures. Sunburn is more common in Texas. High summer temperatures can kill the tree’s cambium tissue from sun exposure on the south or southwest side of the tree’s trunk.
What are the symptoms? In the early stages, sunscald or sunburn can be difficult to detect. The bark on the south or southwest lower portion of the trunk may discolor and some cracking may be visible. Oozing or “bleeding” from the damaged area may appear in the spring. Eventually, the bark will begin to slough off.
In the late stages of damage, cracks or gaps in the bark down to the xylem tissue (interior wood) will appear. There may be evidence of wound healing on the margins of the crack. The loose bark can be carefully removed, but do not tear into or cut into the interior wood tissue. Insects may be visible in the cracked area. Pruning paint should not be applied to the wounded area. Extreme damage can lead to the tree’s death or weakening of the trunk’s strength resulting in breakage.
What types of trees are susceptible? Young or thin-barked ornamental or fruit trees are susceptible to this type of damage. Examples of susceptible tree varieties include maples, fruit (peach, apple, plum), linden, ash, honey locust, Eastern white pine, Texas redbud. In addition, drought-stressed or newly transplanted young trees are more susceptible. Evergreen trees are less susceptible to winter sunscald because the foliage shades the tree’s trunk.
Can sunscald or sunburn be prevented? In Texas, the most important method of prevention is to keep the tree healthy and vigorous with proper watering during the dry hot summer months. Trees should be deeply watered at a minimum of 1 inch of water per week if there is no rain during the growing season. A few deep waterings (1 time weekly) will encourage deep root growth. Frequent shallow watering (2+ times per week) encourages shallow rooting leading to damage during drought.
Some other prevention methods:
- Wrap the lower trunk of young, thin-skinned trees with light-colored materials such as kraft paper or breathable white fabric tree wrap. Be sure not to girdle the trunk when installing the wrap, e.g., do not use wire or zip ties to hold the wrap in place. Leave the wrap in place for several years until the bark is thick and textured enough to withstand extreme temperatures or the canopy of the tree is large enough to shade the trunk.
- Avoid transplanting trees during hot summer months. The ideal time to plant trees in North Texas is late fall to early spring.
- Apply a 1 to 2-inch layer of mulch in the root zone of the tree, keeping the mulch away from the tree trunk and root flare. The trunk and root flare should be exposed.
We recommend engaging a certified arborist to help assess the health of your trees. To find a certified arborist that works in your area go to this website from the International Society of Arboriculture: https://www.treesaregood.org/findanarborist.
If you determine you need to replace your trees, this site from Texas A&M Forest Service will help you find the best tree for your landscape: https://texastreeplanting.tamu.edu/.
Check out these websites to learn more about sunscald and sunburn in trees:
“Sunscald on Trees” (2021). University of Arkansas Cooperative Extension Service: https://www.uaex.edu/yard-garden/home-landscape/trees/sunscald-on-trees.aspx
“Environmental Injury: Sunscald and Sunburn on Trees” (2016). Washington State University Extension. http://pubs.cahnrs.wsu.edu/publications/wp-content/uploads/sites/2/publications/fs197e.pdf
A: The freeze definitely caused this sudden leaf drop. As you may know, a normal leaf drop happens this time of year, so these leaves would have been lost anyway. Usually, old-leaf loss and new-leaf growth happen gradually, so we never see live oaks nearly leafless in spring.
Give it time, and don’t give up hope. As temperatures warm, many plants in our landscape will begin to awaken, including our important live oaks. In fact, if you look closely now, you may start seeing new leaf buds appearing on stems. Early leaf buds appear as tiny, brown nubs; as the buds mature, they turn a lively green and begin to enlarge. Live oaks in your landscape may undergo bud maturity on different timetables, so don’t worry if one tree has green leaf buds and others do not. The following article should be helpful reading.
A thorough article on what you might be seeing in your landscape and how to manage recovery:
Excellent video of Denton County Master Gardener Association President Kathryn Wells discussing post-freeze care:
Our Help Desk has answers for all your questions from asparagus to zucchini. And be sure to check out the vegetable gardening page on dcmga.com.
A: Wild carrot (Daucus carota), also known as Queen Anne’s Lace, is often mistakenly identified as poison hemlock (Conium maculatum), and it is more likely what is growing in your backyard. Both are weeds, but the control method may be different once correctly identified.
Poison hemlock is in the same family (Apiaceae) as carrots, celery, parsnips, and several herbs, including parsley, cilantro, chervil, fennel, anise, dill, and caraway.
Poison Hemlock vs. Wild Carrot
Stems (Fig 1): The most distinct visible difference between poison hemlock and wild carrot is the stems. The poison hemlock’s stem has purple blotches, is “hairless,” and hollow. Wild carrot’s stem is green (young plants), burgundy-green (mature plants), and “hairy.”
Foliage (Fig 2): Although both species have fern-like leaves, there are some differences in the leaves. The leaves of poison hemlock are sharper in detail, up to 2 feet long, and glossy dark green without “hairs.” Wild carrot leaves are lacy or feathery, shorter (2-6 inches long), and nearly hairless to bristly-haired.
Flowers (Fig 3): The flowers of poison hemlock and wild carrot are more similar. Both have white flowers clustered at the end of the stem that are flat, umbrella-like.
Scent: When crushed, the leaves and stems of poison hemlock have an unpleasant odor, whereas the leaves and stems of wild carrot smell like carrots when crushed.
Habitat: Poison hemlock and wild carrot are considered invasive plants found in fields, pastures, vegetable crops, orchards, roadsides, and other disturbed places. Wild carrot is typically found in sandy or gravelly soils, and poison hemlock prefers moist soils.
Impact: Of course, there’s a significant difference in the effect of poison hemlock vs. wild carrot. Poison hemlock is toxic to livestock and humans through ingestion. Cases of human poisoning are relatively rare. The toxin affects the nervous system and can result in fairly rapid death in livestock that feeds on poison hemlock in fresh foliage, stored silage, or contaminated hay. The sap of poison hemlock can also cause contact dermatitis.
Management & Control
The management of both poison hemlock and wild carrot are similar.
- Inspect areas frequently for new infestations. Young plants of both species start as rosettes of foliage.
- Mechanical removal is preferred using a spade or trowel. Wear gloves and long sleeves to avoid skin exposure to the sap of poison hemlock. Be sure to remove the entire taproot to prevent regrowth. Discard the plant in the trash, do not compost or burn it.
- Mowing frequently before flowering begins or plowing or cultivating the area will disrupt the seed germination cycle. Bag and discard the clippings to avoid inadvertently dispersing seeds.
- Use herbicides only as a spot treatment on seedlings or small rosettes. Mechanically remove mature plants. Large infestations may be treated with herbicides containing active ingredients 2,4-D, triclopyr, or glyphosate. Fully follow label instructions about protective clothing and treat carefully to avoid overspray. You can use an empty six oz. can (from tomato paste, for example) with both ends removed to guard against overspray.
Learn more about poison hemlock and wild carrot from the links below.
Sources & Resources
“Poison Hemlock,” University of California Agriculture & Natural Resources
“Wild Carrot,” University of California Agriculture & Natural Resources
“The ‘Don’t Touch Me’ Plants,” Purdue University Extension
A: Weed control is the “ugly” part of gardening. Here are some recommendations and tips:
- You may need to put a weed barrier down such as cardboard each season. Weeds are determined to grow and will overwinter in your soil only to show up again next year. Particularly in sunny spots, you may have to put cardboard down in the early spring each season.
- Prepare a lasagna garden bed this fall where you plan to grow vegetables in the spring. This is a method of sheet composting that includes layers of organic materials and compostable weed blocks such as cardboard or newspaper to enrich your soil without tilling.
- Mulch, mulch, mulch!!! After putting cardboard down, you can put soil on top of that, then apply a 3 – 4″ layer of mulch. This makes a huge difference in tamping down weeds. It has corollary benefits of holding moisture in the soil and moderating the soil’s temperature. Hardwood, cedar, cypress, and pine straw mulches are all good options according to Texas A&M AgriLife extension. Contact tree service(s) to see if they will drop off their chipped tree trimmings to use as mulch.
- Apply a pre-emergence herbicide rated for vegetable plants; it’s designed to prevent weed seeds from sprouting. An organic example is corn gluten meal, which also contains 10% nitrogen that acts as a fertilizer. Another example rated for vegetables is products containing trifluralin. Both of these may require repeated applications to achieve weed control over the entire growing season. Always read the entire product label and carefully follow the instructions and safety precautions.
- Consider planting a cool-season cover crop such as buckwheat or winter rye this fall to enrich the soil and keep cool-season weeds at bay.
- Unfortunately, even with using a weed barrier and mulch, you’ll still have a few weeds pop up during the growing season. Monitor your beds daily, and dig out any new weed growth as they pop up. Do your best not to let the weeds flower and go to seed. You may find you need to discard the weed plant material you remove rather than composting it, particularly if you plan to use the compost in your beds. Weed seeds seem to be able to survive even the hottest compost pile!
Sources & Resources
“Mulching” – Texas A&M AgriLife Extension
“Vegetable Resources; Chapter VIII: Weed Management” – Texas A&M AgriLife Extension
“Gardening & Landscaping, How to Grow Vegetables” – Texas A&M AgriLife Extension
“Get an Early Start on Vegetable Weed Garden Control” – Michigan State University Extension
“Using Cover Crops and Green Manures in the Home Vegetable Garden” – Wisconsin Horticulture Division of Extension
“Fall Ground Preparation” – Texas A&M AgriLife Extension, East Texas Gardening