Garden Geek: Common Complaints and Questions

Planting and pests are two topics that try even the most experienced gardeners. Fear not, the Garden Geek’s got the answers.

At this time of year, there are two things I get an earful of: what’s eating my Texas mountain laurel and when do I fertilize my lawn.

One is easy to explain. For the other, refer strictly to the expertise that is Garden Style San Antonio.

First, I’ll address the Texas mountain laurel (Sophora secundiflora). This small tree prefers to grow in full sun in rocky, alkaline soil (most of north Bexar County soil). Too often homeowners try to grow them in mulched beds, or worse, the lawn.

When native plants are indulged with human care, they frequently become susceptible to increased pest attacks. The most devastating to the Texas mountain laurel is the caterpillar of the genista moth (Uresiphita reversalis), a rather pretty gold and white caterpillar, which is voracious in its appetite for new mountain laurel leaves. Treating native plants with indifference is sometimes the best option.

If the caterpillar infestation becomes extensive, treat by applying a powder or spray containing Bacillus thuringiensis, or Bt for short, or one containing Spinosad. Both of these are organic treatments. If the problem persists, use a powder or spray containing Carbaryl, a mild insecticide.

Of course, planting the right plant in the right place is always the first and best option.

As for lawn fertilization, turf species are still dormant until at least the middle of April so any fertilizer applied any earlier than that is a waste of time and money.

Also, cool season weeds will begin to die off in about six weeks so there’s no need to spend money on herbicides. Truthfully, the best weed killer is frequent mowing and the best fertilizer (after you’ve bagged the weed seeds) are the grass clippings left behind from mowing.

But don’t take my word for it. Visit where you’ll find all this info and more — including a month-to-month maintenance schedule for your landscape.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
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