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Rockwall County Master Gardener Summer 2022 Newsletter

June - July - August

In this issue...

Crapemyrtle bark scale

Iron chlorosis in plants

Growing plants in shade

Ask a Master Gardener

Vegetable planting guide

Our favorites

Community news


Upcoming events

Featured articles

Crapemyrtle bark scale:

coming to a yard near you!

Why pay attention to this MESSY pest?

This messy pest, Crapemyrtle Bark Scale (CMBS), was first identified in the United States in 2004 in Richardson, Texas. Given that crapemyrtles are extensively used in landscapes, there is a possibility of further spread and significant economic impact to growers, retailers and homeowners. CMBS is also being hosted on plants other than crapemyrtles. Some of those alternative hosts include boxwood, soybean, fig, apple, and blackberry. CMBS has also been identified on native hosts such as beautyberry and hackberry. 

How to identify crapemyrtle bark scale?

CMBS may first be noticed by the sooty mold on leaves, twigs, and branches of the host plant. With more close inspection, the scale, which is white and has a felt-like appearance, can be found in the crotches of the higher branches and, if the host is heavily infested, on the trunk, branches and twigs. The twigs may be entirely covered with the scale. The insects will “bleed pink” when pressed or crushed. The CMBS’ pink exudate, when crushed, is one factor distinguishing CMBS from crapemyrtle aphids. Aphids are small, soft-bodied insects that vary in color and may or may not have wings. CMBS is rarely found on the leaves. Aphids, in contrast, feed primarily on the leaves.

Understanding the “modus operandi” of CMBS.

CMBS feeds by sucking sap from the phloem of the host plant. CMBS can complete 2-4 generations in a single growing season and is able to overwinter in any life stage. The nymphs suck the sap and secret a honeydew-like waste. This honeydew then molds and produces the sooty MESS which covers the crapemyrtle and eventually the plants beneath it. CMBS may be transported by birds or flying insects. It also can be readily transported by gardeners, landscape equipment and inadequate disposal of diseased plants.

As an introduced species, CMBS has few natural enemies here. Lady bugs/beetles, such as the twice stabbed lady beetle, feed on CMBS and can help control it. 

Recommended CMBS management/control strategies:

Monitor – Watch for early signs of infestation to support timely application of control measures.   

Biological Control – Care should be taken to preserve natural enemies to CMBS. Lady beetles provide 75% suppression. Do not disturb the lady beetle pupa found on infested trees (refer to picture below).


Chemical Control – Effective chemical control may require two types of application, bark spray and drench application. Read and follow manufacturers’ directions when using any of these agents. 

Bark spray will be effective when crawlers are out, which in our area is usually the end of April through the first week of May. Dinotefuran, pyriproxyfen, buprofezin are the active ingredients which have demonstrated the most success. Multiple applications of bark spray may be needed.

Drench application is best completed very early in the season at the time of leaf budding. It will take approximately 60 days for the “drench” to move throughout the host plant. The active ingredients showing the most success for drench application include imidacloprid and dinotefuran. A YouTube video by Texas A&M AgriLife Extension Services Professor Mike Merchant, demonstrates chemical drench control methods. It may be necessary to use the drench control method for several years, given the ability of the CMBS to overwinter.

Iron chlorosis in plants

Have you ever had a plant grow new yellow leaves with green veins instead of its usual green leaves? Or grass with its blades striped green and yellow or completely yellow? This is a symptom of iron deficiency, and the affected plants need more iron than our alkaline soil has available. Iron may be present, but a high soil pH of 7 or more makes it chemically unavailable to the plants. Treating with simple elemental iron, as some use on lawns, does little good because the iron is immediately tied up in the alkaline soil. Plants take iron into their systems from the soil through their roots. However, it must be soluble in water for that to happen. Under alkaline conditions, iron converts to an insoluble form.

Environmental factors such as temperature, rainfall and light intensity also impact iron uptake and assimilation by plants. Low soil temperatures reduce soil microbial activity which, in turn, reduces iron uptake. Wet soils, or excessively dry soils, and low light also reduce iron uptake. For example, iron chlorosis is common in St. Augustine grass under shaded conditions. High phosphorus levels from excessive fertilization will tie up iron and make it unavailable to plant roots. Iron deficiency (chlorosis) will always appear on the newest growth (leaves at the growing tips of the branches) first. Leaves will at first be lighter green or yellow, with veins remaining dark green the longest. Leaves do not fall from the plant. The entire leaf may turn yellow and brown edges may begin to show up.

The best solution for acid loving plants is to plant them in soil with a pH value of 4.5-6.5pH. However, if your plant has a severe problem and you need a quick fix, applying liquid iron will work for a short period of time. Liquid iron is most effective when used as a foliar spray. Other options include the use of iron/sulfur materials to supply soluble iron and help acidify the soil via the sulfur. Your plants don’t necessarily need the sulfur, they just need the effect the sulfur has in lowering the soil pH. Or you can use chelated iron products for longer-term correction. The chelating provides buffering action against the alkalinity of the soil. Chelated iron is the best solution and lasts the longest. Apply iron products at the drip line of trees and shrubs. This is the area that plants take up nutrients and water from their roots. Residue from iron products will leave stains that are difficult, if not impossible to remove. Be very careful when applying iron near walks, drives, patios, fences, walls and houses. Continue reading about chelated iron and the different products available here

Growing plants in shade

While those mature, shady trees are often highly sought after and considered to be an asset in many yards, it can be difficult to know what you can successfully grow under them. It is possible to grow plants and even flowers in full shade and dappled (filtered) sun, you just have to choose a plant with the correct light requirements. Caladiums, elephant ears and coleus are popular choices but also consider the following plants for your shade garden:

Flowering annuals for shade:

Impatiens – produces brightly colored, cheerful flowers.

Annual Vinca (common periwinkle) – thrives in heat and is semi-shade tolerant. ‘Cora’ vinca is disease resistant and trailing varieties work great in containers.

Green Leaf Begonia – produces pink, white, or red flowers with green shiny leaves.

Perennials for shade:

Texas Gold Columbine – a flowering plant with large, yellow-gold spurred flowers in spring.

Hosta – clump forming plant with attractive foliage that blooms on long stalks in the summer.

Oakleaf Hydrangea – giant white floral heads in spring turn a rich red color in fall.

Vines and ground cover for shade:

English Ivy  woody vined evergreen ground cover or climber.

Asian Jasmine – dense, evergreen ground cover with dark green, glossy leaves.

Evergreen Clematis – flowering evergreen vine with large leathery green leaves and white star-like blooms.

Shrubs and bushes for shade:

Leatherleaf Mahonia – colorful shade shrub for all seasons. Produces fragrant flowers in late winter and blue grape-like clusters of fruit in spring.

Indian Hawthorn – medium sized, low maintenance evergreen shrub.

Dwarf Yaupon Holly – evergreen, produces small red berries in the winter.

Ask a master gardener

How can I keep my lawn looking healthy all year long?

A healthy lawn needs good soil. Regular mulching of lawn clippings into the grass evenly spreads many nutrients back into the soil. As it decomposes, mulched grass releases nitrogen and many other essential nutrients that your grass needs to grow, and, your soil needs to stay healthy.

Mulching reduces soil compaction and erosion, suppresses weeds, captures and retains soil moisture, protects roots from summer heat, protects plant crowns from winter cold, and protects and stimulates microbial activity in the soil. Additionally, a healthy lawn also comes from choosing the correct turf for your light conditions (sun/shade etc.), traffic areas, and lawn use. Check out Turfgrass Selection for Texas for specific lawns in Texas.

Other useful practices include:

Lawn aeration once a year to improve drainage and reduce soil compaction.

Morning watering is best, wetting the soil to a depth of 4-6 inches, allowing soil to dry out between watering.

Mow no more than 1/3 of the leaf blade off with each mowing.

Mow in a different direction each time you mow (diagonal, Right/Left, Left/Right).

Before fertilizing, use a test kit from your local extension office to determine which nutrients are lacking or already present in your soil.

More information can be found at Earth-Wise Guide to Lawn Problems.

Summer vegetable guide

Vegetable gardening with Laura!

Texas summers get pretty hot, and while there are a few heat loving vegetables (like okra!) vegetable harvests in summer can be thin due to the heat. Don’t be surprised when your indeterminate tomato plants you planted this spring keep growing but don’t set fruit this summer – they need temperatures cooler than our typical summers. They’ll be ready for a bountiful harvest in the fall! Summer is a great time to get ready for the next prime growing season – Fall! Fall weather, like spring, is ideal for most vegetables with warm days and cool nights. Read ahead for what to plant and when so you have a bountiful fall harvest!


Seed  cantaloupe, cucumber, eggplant, okra, and watermelon.

Transplant  cucumber, eggplant, peppers, and tomatoes.


I have added a section titled “Indoors” – these are cool season vegetables you can get a head start growing by starting their seeds indoors for transplant in the fall. When the fall newsletter comes out, you’ll be ready with transplants!


Seed  beans (pole, bush), black-eyed peas, cantaloupe, corn, cucumber, eggplant, okra, potatoes, pumpkins, southern peas, summer squash, watermelon, winter squash, and zucchini.

Transplant – cucumber, eggplant, okra, peppers, pumpkins, tomatoes, and winter squash.

Indoors  broccoli, Brussels sprouts, cabbage, cauliflower, greens (collard, mustard), and spinach.


Seed  beans (pole, bush), black-eyed peas, corn, cucumber, potatoes, pumpkins, southern peas, summer squash, winter squash, and zucchini.

Transplant  cucumber, okra, pumpkins, tomatoes, and winter squash.

Indoors  broccoli, Brussels sprouts, cabbage, cauliflower, greens (collard, mustard), and spinach.


Many herbs featured in the spring newsletter will continue to thrive in the heat of summer (be careful with mint – it may thrive too much!). Annual herbs, such as basil, can thrive to the point of bolting (flowering). While flowers are usually what we want and are great for pollinators – bolting can change the flavor of the herb for the worse. Let a few plants go for the pollinators, but overall bolting is a sign to harvest that basil and make a big batch of pesto to freeze! 

Click here for a full list of vegetable planting dates and visit the Texas vegetable gardening guide for more information. 

Our favorites!

What do we grow in our home gardens?


"Gardenias are an evergreen flowering shrub with deep green leaves and lovely white, very fragrant, 2”- 3” flowers that bloom spring through fall. They prefer 4-6 hours of sun (morning sun with afternoon shade or all day filtered sun) and soil with a

pH of 4.5 - 6.0." 

-Cathy G.

Community news

What have we been up to?

Rockwall Farmers Market

Royse City ISD Ag Days

Maintaining our Discovery Garden

Royse City Garden Club lectures

Planting flowers at Courthouse

Annual Rockwall Youth Fair

Spring Plant Sale


Upcoming events...

We are working hard to open our Fall Plant Sale to the public! Stay tuned for details!

Also, coming this fall,  "A Walk Through the Garden" with a look at perennials, woody stem perennials and annuals. Short educational sessions with Master Gardeners. And Master Gardeners will be available to help answer gardening questions and provide insight into gardening 101. Stay tuned!

Come see us at the Rockwall Farmers Market every 2nd and 4th Saturday of the month! May thru September 8:00 am to 12:00 pm at the Rockwall Downtown Square.

Please take our short Rockwall County Master Gardeners Survey to help improve our educational outreach.

Wednesday Gardening Hot Line: “Ask a Master Gardener!” Volunteers will be answering calls and emails every Wednesday from 10:00 a.m. until 12:00 p.m. Call (972) 204-7660 or email us anytime at:

Take our poll!

How do you support pollinators?
Plant pollinator-friendly plants to provide pollen and nectar.
Give bees nesting places in my landscape.
Plant host plants for caterpillars.
Reduce or eliminate pesticide use in my yard.
Dedicate a part of my landscape to wildflowers.

Spring Polling Results:

In our spring issue we asked if you have visited our booth at the Rockwall Farmers Market. 50% of survey takers said they did not know we were at the farmers market. Come on by and say hi!

Contact us

Rockwall County Master Gardener Association

915 Whitmore, Suite B

Rockwall, Texas 75087

972-204-7660 | | website | facebook

Join Our Newsletter E-mail List


Michele Campbell, Editor

Contributing Writers: Virginia Davis, Cathy Grinstead, Jordyn Rodriguez,  Kim Townsend, Laura Wheelis, Todd K. Williams

EnviroSmart is published by: Rockwall County Master Gardener Association part of Texas A&M ArgiLife Extension Service, the Texas A&M University System. The information given herein is for education purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas A&M AgriLife Extension is implied.

Todd Williams - County Extension Agent

Ag/ Natural Resources


Texas A&M AgriLife Extension provides equal opportunities in its programs and employment to all persons, regardless of race, color, sex, religion, national origin, disability, age, genetic information, veteran status, sexual orientation or gender identity. The Texas A&M University System, U.S. Department of Agriculture, and the County of Commissioners Courts of Texas Cooperating.

Online resources:

Texas A&M Horticulture

Texas Master Gardener

Rockwall County Master Gardeners