Keith Hansen

What a difference a year makes! The effects of our extended drought are showing up this year as many oaks and other trees and shrubs are showing signs of stress.

The last few years have been extremely stressful on trees, and the cumulative effects weaken trees, making them more susceptible to diseases.

The abundant rainfall has recharged the soil moisture, but in some cases, may be causing other problems due to prolonged saturated conditions.

I certainly won't go out on the limb and predict the weather, but August is typically a drier and hotter month. As rains become less frequent, you will need to get the irrigation system running again.

Little showers may fool you into thinking we're getting enough water. Use a rain gauge to actually measure how much rain you're receiving. Lawns and shrubs need about an inch of water per week in the summer. If we get an inch of rain, you probably do not need to water. Make the best use of irrigation water by giving plants a thorough soaking as infrequently as the weather and your soils will allow.

Check the thickness of mulch around your shrubs, flowers and newly planted trees. Unmulched soils can reach more than 100 degrees, hot enough to kill tender surface roots.

Mulched soils can be three to 10 degrees than bare soil. Besides reducing soil temperature, mulches conserve water by reducing evaporation. In one test, pine needles gave the greatest reduction in soil evaporation. Mulch also reduces weeds that compete for water.

Chinch bugs can be major lawn pest of St. Augustine in the summer, especially once it gets hot and dry. If patches in the lawn look dry, appearing to need water, then chinch bugs could be the culprit.

Gray leaf spot fungus is still a problem in some St. Augustine lawns, especially in shady spots and areas that tend to remain wet. Symptoms include random yellow patches of lawn, small black spots on the leaves, and in the worse cases, the grass severely thins, like it is melting away.

Azalea lace bugs are the most common insects that damage azaleas.

Affected azalea leaves look like they are stippled until they are almost white. A look on the underside of leaves will reveal black, varnish-like spots which is a sure sign of azalea lace bugs. Spray with an insecticide, making sure the spray contacts underneath the leaves where the lace bugs are feeding.

Black spot on roses has been more intense this year due to all the rain. Leaf spot fungal diseases need prolonged leaf wetness in order for fungal spores to germinate and grow into the leaves, creating the infections that show up as spots.

Black spot will cause rose leaves to drop, leaving bare canes.

This puts a lot of stress on a rose plant as it works to replace lost leaves.

For rose varieties that are prone to black spot, keep up with a regular fungicide spray program to keep the leaves healthy.

If roses get weak and die, consider replacing them with one or more of the rose varieties designated as Earth Kind, those with increased resistance to black spot and can tolerate minor defoliation without major injury.

For a list of Earth Kind roses, go to: http://earthkindroses.tamu.edu.

Use pesticides with caution and only as needed. Follow all label directions and never increase the rate. Do not rinse sprayers or dispose of excess spray in the drain, storm sewer or other place where runoff can contaminate our water treatment system.


VEGETABLES

Starting in mid August, plant broccoli, Brussels sprouts, cabbage, Chinese cabbage, carrots, cauliflower, Swiss chard, collards, kale, English peas, Irish potatoes, and summer squash.

Set out tomato transplants (if you can find them) right away for a fall harvest. Look for an early maturing variety (65 to 75 days). Remember that our average first freeze is mid-November and that tomato maturity slows down as the days get cool and cloudy.

Peppers and tomatoes planted earlier this year will not set fruit during the heat of summer, even though they may still be flowering. If the plants remain healthy, they will set fruit again once temperatures stay below 90 degrees. Side dress established healthy plants with fertilizer and keep watered to encourage new growth.

Bell peppers and tomatoes should be fertilized regularly to keep the plants producing abundant leaves that will prevent sunscald of the developing fruit.

Remove old plants that have become unproductive to eliminate shelters for insects and disease organisms. Weeds also harbor potential insect pests, so keep the garden mulched and weed free.

ODDS AND ENDS

It is not too late to set out another planting of many warm-season annuals such as marigolds, zinnias and periwinkles. They will require extra attention for the first few weeks, but should reward you with color until first freeze in November.

Pinch faded blooms off of annuals to prevent seeds from setting. This will redirect the plant's energy into forming new flowers.

Order your spring-flowering bulbs now. One source of hard-to-find bulbs is the Fall Bulb Sale Smith County Master Gardeners are holding on Sept. 8 in conjunction with their annual Fall Gardening Conference at the Tyler Rose Garden Center and Harvey Convention Center. Uncommon, hardy and heirloom bulbs will be available. These are varieties that are well-adapted to our area and will naturalize and rebloom for many years in East Texas. See the Smith County Master Gardener Web site for more details, including the new photo contest/exhibit at this event: EastTexasGardening.tamu.edu - - click on "Master Gardener.''

Outdoor potted plants probably need watering daily to prevent wilting. Such frequent watering leaches out nutrients, so regularly fertilize potted plants with a water-soluble fertilizer.

Also, other garden plants can probably use a shot of fertilizer to compensate for lost nutrients due to the abundant rainfall that has leached away nitrogen and other water-soluble nutrients.

This is the last month to plant lawns in order to give the new grass opportunity to become fully established before cold weather stops growth.

Wait to fertilize established lawns until late September or early October.


Keith Hansen is Smith County Horticulturist with Texas Cooperative Extension. His Web page is http://EastTexasGardening.tamu.edu Texas Cooperative Extension educational programs are open to all individuals without regard to race, color, sex, disability, religion, age or national origin.

Keith Hansen
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