Gardening with Laurie: Some insects essential for plant reproduction

By Laurie Garretson
Aug. 16, 2012 at 3:16 a.m.

Laurie Garretson

Laurie Garretson

As most gardeners know, the hot, dry weather brings out the pests. One of these pests many of you are dealing with right now is aphids, particularly on crape myrtles. As I mentioned in last week's article, these tiny pests are sucking insects that suck vital nutrients out of plants.

As the aphids feed, they secrete a sticky honey dew substance that collects on the foliage of the attacked plants and will also drop on anything under or around the plant. After a while, mold will develop on the honey dew causing foliage to turn black.

This is usually when people first notice that something is going on with their crape myrtles. Unfortunately, many of these same people assume that their plants have a fungal disease and treat the plant with a fungicide. Fungicides do not help in this case.

To stop the black mold that is growing on the leaves, you will first have to get rid of the cause of the honey dew excretion from the aphids. This means spraying the plant with an insecticide, releasing some ladybugs (aphids are their favorite meal), using a strong blast of water from the garden hose to blow the aphids off or do nothing at all.

Let me clear up another common mistake that many well-meaning gardeners often make. First, let me share a story. Many years back, I received a call from a very sweet, elderly lady that wanted to let me know something about a holly fern plant that she had bought from me.

She very politely explained that it had taken her all weekend to clean off all the insects that were on the back of the foliage of her fern she had recently purchased. She wanted to let me know so I wouldn't sell the infected plants to anyone else. Well, it took me several minutes to get her to understand that those insects she so painstakingly removed were in fact essential for the plant's reproduction.

Holly or river ferns have spores on the underside of their leaves. It's understandable that not everyone knows this. And I can see how she took them for pests. Spores are beneficial to these plant and not something to get rid of.

In some cases, you could find scale insects on these plants, but they usually would be located on the stems and on the tops of the leaves, as well as the undersides. Beneficial spores are only found on the undersides of the foliage.

Another common problem usually made by new gardeners is about drought-tolerant plants. Over the years, I've had so many well-meaning, new gardeners tell me that a certain plant of theirs died for no apparent reason.

After my usual questioning session, I find that they didn't water the plant. Being drought tolerant, they assumed the plant was OK on its own. They learned the hard way that being drought tolerant only means after it has gotten established. It can take anywhere from one to two years for a plant to develop a good root system. Until that time, the plant will occasionally need to be watered.

Until next time, let's try to garden with nature, not against it, and maybe all our weeds will become wildflowers.

Laurie Garretson is a Victoria gardener and nursery owner. Send your gardening questions to or in care of the Advocate, P.O. Box 1518, Victoria, TX 77902.



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