Summer heat hard on plants

Published 1:30 am Sunday, June 22, 2008

We are now beginning to feel the burn of the summer sun and the real heat is yet to come.

Obviously, many of you are aware that supplying water is essential for maintaining all types of gardens in these climates. There are also several other factors that are beginning to have an impact on plants and here are some ways to address them.

Q: My azaleas look horrible and I have fertilized them well, what could be the problem?

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A: I have looked at several azaleas this year that are appearing stressed due to lack of water, insects and poor management.

Azaleas like most plants do need food in the form of fertilization. Even though complete fertilizers like 13-13-13 do have great uses for plant performance, we do not recommend repeated applications of triple 13 for azaleas.

Use an Azalea-Camellia fertilizer if you are fertilizing established azaleas or camellias, this will make much more of an impact and be much healthier for the plant.

In addition, more calls have been coming in about azalea leaves becoming spotted on top. This is likely due to lace bugs feeding on the underside of the leaf. Turn the leaf over and you might be able to see the small pest about an 1/8 inch long with lace wings and black body.

Hi-Yield 38 Plus, Turf, Termite & Ornamental Insect Control or Bayer Advanced Garden Rose & Flower Insect Killer are effective treatments for lace bugs, please remember to read the label before use.

Q: Why are my pecan leaves falling with big bumps on them?

A: Phylloxera is an aphid-like insect that causes tumor-like galls or growths on the stems and leafstalks of pecan trees.

Here are a few things to know. Once you get these growths on the leaves the damage is done and any attempt to change this is a waste of time and money for this year.

Secondly, phylloxera populations are cyclic and trees that are severely damaged one year will often recover in subsequent years and may go several successive years without sustaining a serious infestation. Some varieties are less susceptible than others but there is no reason to remove trees with this problem.

In order to prevent this, trees have to be sprayed before bud break usually around April 1, however to spray a mature pecan tree takes a commercial sprayer which usually makes spraying these trees not an option for homeowners.

A better option would be to use a product like Bayer Tree and Shrub Insect Control with the active ingredient imidacloprid in early September. This is a liquid drench that is used around the tree that works into the vascular system of the tree to control several different pests the following year.

Just a follow-up to last week’s article, if you still want some tomatoes to eat this fall it is not too late to plant cherry tomatoes, which are very heat tolerant and should provide tomatoes well in to the fall.

David Carter is the director of the Adams County Extension Service. He can be reached at