WILSON COUNTY NEWS

Calvin R. Finch, Ph.D., Conservation Director, San Antonio Water System,

and Horticulturist

Week of June 11, 2001

 

Q.                Is there anything that will control grasshoppers on my oak trees?

 

A.                 Many common insecticides will kill grasshoppers if they are sprayed directly. The insects are so large and so mobile, however, that it is not usually practical to kill every wave. Your oaks will re-leaf without permanent damage.

 

Q.                The leaves on my peach tree are falling off. First, they show red spots that fall out and then the leaves fall. Luckily, it doesn’t have much fruit. I am afraid that the whole tree will defoliate. Any ideas?

 

A.                 The problem you are describing is probably bacterial leaf spot. Unfortunately, there is no spray for it now. This fall, just before the leaves fall, spray Kocide 101 (cupric hydroxide). This copper spray causes the tree to defoliate and will reduce the disease pressure next spring.

 

Q.                What are the yellow tubular flowers that I see blooming all over town? They look great.

 

A.                 The plant is Esperanza (Tecoma stans) or Yellow Bells. It is a good xeriscape plant for full sun that is deer proof. Esperanza usually dies back to the roots every winter, so only reaches 5 or 6 feet tall. Plants in sheltered areas where they do not freeze easily reach 8 or 9 feet tall.

 

The nursery selection ‘Texas Star’ is a blooming machine that is covered with blooms when it reaches 1 and ½ feet tall. There is an orange variety that is leggy and blooms less bountifully.

 

Esperanza, along with poinciana (orange flowered, airy plant) and firebush (red hummingibrd flowers), are my choices for the best full sun plants for a droughty summer.

 

Q.                There is a purple blooming small tree I see on the highway medians and in some yards that I really like. The flowers look like small candles. What is it?

 

A         You are describing vitex. It is also called chaste tree. Hummingbirds and butterflies enjoy its nectar. Deer do not seem to eat it and it is invincible to drought and heat. Vitex will reach 25 feet tall on good soil but most are 12 to 15 feet tall.