While rising temperatures are usually a concern this time of year, the higher than normal amount of rainfall this spring has waterlogged soils, which can be a problem. Water is essential to plant survival, but it can be challenging to landscapes in excessive amounts. Most plants in the area seem to be doing OK, but others are showing the effects of saturated soil.
This condition affects a plant's entire physiology — reducing available oxygen, slowing photosynthesis and a host of other processes. For example, plants that require well-drained soils such as rosemary or mountain laurel and more drought tolerant plants such as salvia or red yucca may be underperforming or declining.
Leaves of some trees, shrubs and even lawns are yellowing, turning a lighter shade of green. This can be the result of rainfall leaching nitrogen from the soil. If you see this in your yard and plan to fertilize, we recommend soil testing to learn the levels of essential nutrients that are deficient. Find testing information at soiltesting.tamu.edu.
Even without rainfall, days on end of cloudy, overcast skies have reduced sunlight that is critical to photosynthesis. With less sunlight, some plants produce fewer flowers or stems and branches grow long and spindly.
Seemingly healthy trees, even mature ones, are uprooting and falling over. This could be the result of recent periods of high winds, but also due to erosion or hidden issues like root rot.
Rainy weather conditions can promote fungal diseases, which require a period of prolonged leaf wetness to develop. For instance, roses may have increased incidence of blackspot causing yellowing and leaf drop.
Gray Leaf Spot is somewhat common on St. Augustine grass. Particularly in shaded areas, this fungal disease can develop rapidly in prolonged periods of moisture and warm temperatures. Leaf spots are ash-colored with purplish brown margins and can cause turf to thin and turn yellow.
Eliminate a source of fungal disease infection by raking and disposing of affected leaves — blackspot affected leaves of roses, entomosporium infected foliage of Indian hawthorn shrubs and cercospora leaf spot affected leaves of ligustrum and crape myrtle.
Erosion and drainage issues
If your landscape has erosion or drainage issues, they’ve been exacerbated by spring rains. Use this opportunity to closely observe the flow of water, then investigate solutions and take measures to tackle the problem once things begin to dry out.
A method to address drainage or erosion is to capture runoff via cisterns, barrels or a rain garden. Also, runoff can be redirected using a swale, a French drain, a catch basin or extending a downspout.
Monitor for insects! Leaf-footed bugs and squash vine borers are active now in vegetable gardens. Manage with traps or row covers. Aphids and leaf hoppers can infest crape myrtles. Blast off aphids with a strong stream of water. Leaf hoppers do not typically occur in large enough numbers to do real harm but are a nuisance.
Watch for bagworm caterpillars that may be gobbling foliage of junipers, arborvitae and cypress. They build a little cone-shaped bag that they carry with them as they feed. The simple control measure is to remove the insect with bags and dispose of them. Or if the caterpillars are visible, apply a pest-control aid such as Bacillus thuringiensis (Bt).
Some colorful summer annuals and perennials that can withstand summer’s heat can still be planted, including coleus, ornamental sweet potato vine, trailing lantana, tropical hibiscus, mandevilla and vinca. Sow seeds of zinnia, moss rose and sunflower for easy, dependable summer color. Plant new lawns from sod, seed or plugs.
Central Texas gardens and orchards are bursting now with ripe fruits and vegetables. If you would like to get in on the bounty, there is still time to plant a few things that actually appreciate summer’s heat. Plant seeds of lima beans, Southern field peas, okra, pumpkin, summer squash, winter squash, cantaloupe, honeydew and watermelon. Also, small plants of cucumber, eggplant, Malabar spinach, peppers, tomatillo and basil.
Prune branches damaged by recent high winds and if possible, place them at your curb for recycling. Abundant spring rainfall spurred lush growth of shrubs, vines and groundcovers. They may be lightly pruned to keep them in bounds. Mow turf at its optimum height — bermudagrass 1 to 2 inches, St. Augustinegrass 2 ½ to 3 ½ and zoysiagrass 1 to 3 inches.
Most lawns have only needed watering once or twice this year, so be prepared for summer irrigation. Inspect your system to see if sprinkler heads are functioning correctly.
Following weeks of rain, the mosquito population is soaring. If you are relaxing in the backyard or working out of doors, take steps to protect yourself from biting mosquitoes and reduce mosquito breeding sites in the landscape.
The 4 'D's
• Dusk/dawn — Avoid being outside when mosquitoes are searching for a blood meal, which is usually in the early morning hours and just before the sun goes down. While some species are daytime biters, most prefer to feed at dusk and dawn.
• Drain — Empty standing water from “containers” around your home and work areas, such as buckets, wheelbarrows, kiddie pools, toys, dog bowls, water troughs, tires and bottles. Make improvements that allow standing water to run off following rains.
• Dress — If out during mosquito feeding hours, wear long sleeves and pants in plain colors. Avoid attracting them by wearing excessive amounts of fragrance.
• Defend — Any time you go outside for an extended period of time, wear an insect repellent.
Charla Anthony is the horticulturist at Texas A&M AgriLife Extension, Brazos County, 2619 Texas 21 W., Bryan, Texas 77803. Send gardening questions to firstname.lastname@example.org.