QUESTION: Leaf miner damage to my columbines is rampant and severely affects the beauty of the plant. I have dreams of selling my seeds and small plantings and would like to be rid of this problem.

ANSWER: It seems that leafminers come with columbines. They defoliate my columbines every year just as they do in the wild. You could prevent them by using an insecticide such as diazinon or dursban every 7 days, but it hardly seems worthwhile. They usually attack and destroy the old foliage on the seed stalks that die naturally after seed ripens. New growth comes from the base which doesn't seem to be damaged as badly. Just cut off the dead seed stems at the top and be rid of the unsightly leafminer damage as well. By that time, the seed will have matured and been harvested anyway.

QUESTION: My cedar elm has developed a problem--the leaves are developing black spots that spread to the entire leaf. The leaf then shrivels up and dies. I tried spraying liquid Sevin but it has not helped. Is this a fungus?

ANSWER: The problem you described is probably black leaf spot, caused by the fungus Gnomonia ulmea. It would need to be examined to confirm this.

The following information was adapted from the Texas Plant Disease Handbook:

Small, yellow spots first appear on the upper surface of leaves, then gradually develop a shiny black appearance. Heavy spotting causes leaf yellowing and early defoliation in wet seasons. Usually, defoliation does not occur much before normal leaf fall so control is not warranted.

If trees have been seriously affected in previous seasons, applying fungicidal sprays when leaves are unfolding, when they reach full size, then again 2 weeks later will help prevent serious defoliation. These fungicidal sprays include triadmefon (including Bayleton and Green Light's Fung-Away), chlorothalonil (including Daconil 2787, Bravo, others), and thiophanate methyl (including Topsin-M and Cleary's 3336).

Raking and disposing of fallen leaves will reduce inoculum for future infection.

QUESTION: Can fire-ant bait such as Amdro be safely used
around vegetable plants- If not, what would be the next best substitute?

ANSWER: It can, but should be used around the outside of the garden according to label instructions.

I recently saw on TV that dry grits (pre-cooked) was an effective fire ant bait. I believe that this was offered as an "organic" solution to fire ants.

We have not had good results using grits -- beside the sound of the exploding ants is annoying!! There are several "organic" insecticides which work quite well.

QUESTION: I recently bought an "Everblooming Hibiscus" and have it in a pot on my screened porch in Blanco. The plant is making lots of buds, but many of them are falling off before they are fully developed. What am I doing wrong?

ANSWER: Hibiscus buds abort because of too much shade and, primarily, damage by very small insects called thrips. Give the plant as much light (at least 8 to 10 hours of direct sun daily) as possible, feed often with Hibiscus Food (a water soluble fertilizer made by Easy Grow) and spray with Orthene insecticide every 7 days for 4 consecutive sprays. That should stop the bud drop.

QUESTION: I have a crushed concrete driveway on our farm. I have tried several different ways to get rid of bermuda grass but without any success. In my latest attempt, I tried a herbicide called "topsite". It proved to work the best, but after 3 months, I noticed it coming back. Any suggestions on how I can get rid of bermuda grass indefinitely ?

ANSWER: As bermuda grass is coming back, apply a glyphosate herbicide such as Roundup or Kleanup. Stronger herbicides such as Ortho Brush-B-Gon or Brush Killer can be used but washing onto desirable ornamentals and trees must be avoided.

QUESTION: I read in Southern Living an article on how to start crape myrtles from seeds. In February I planted seeds in flats and kept them inside my house until April. Then I transplanted them into 6-inch containers and set them outside. I have nice sprouts, but they are about 3-inches tall. When can I plant them in the ground? I'm afraid they still might be a little too tender to withstand summer sun.

ANSWER: Southern Living should give complete information about such a bizarre idea. I trust they mentioned that the seedlings will probably not have the disease resistance and color of the parent tree! Anyway, transplant the seedlings into gallon-size containers filled with a loose potting mix (Osmocote Slow-Release Fertilizer incorporated into the mix). Grow them outdoors in a location that receives morning sun and afternoon shade. Then, wait for several years and see what you have -- probably a waste of time. After the seedlings get 20-inches tall or more in the gallon containers, they can be transplanted into a permanent location which is sunny and well-drained.

QUESTION: I live along the Texas Gulf Coast (Galveston Bay) and have a bad problem with crawfish burrowing in my lawn and leaving their "castles" literally everywhere, especially after a good rain. My soil is mostly clay, or as we call it, "gumbo", with some bank sand and topsoil. I have St. Augustine grass. I would like to know is if there is a product on the market with which I can either spread or spray on my lawn which will discourage these creatures from taking up residence.

ANSWER: Dr. Mike Merchant, PLANTanswers expert entomologist, says:

"I get the crawfish question about 3 times a year. I have seen many agents and entomologists dance around the crawfish hole trying to come up with a solution, resulting in many recipes. Unfortunately, there are no published tests and no current pesticides labeled for this purpose.

Louisiana State University does include a crawfish recommendation in their Extension guide. Mix Sevin 50W at rate of 8 tablespoons per gallon. Apply 1 quart per hole. Presumably, this has been tested, but it is not on the label. Crawfish are susceptible to a variety of pesticides, but the best solution is probably establishing good drainage in the lawn."

Another expert on eating crawfish says that this Sevin insecticide will give the meat an off-flavor. That's according to Dr. Frank Dainello, Cajun extraordinaire!

QUESTION: On a recent trip from North Carolina to San Antonio, we passed through Austin and noticed several trees by the road that resembled the lavender plant but on a very large scale. The branches on the tree were swept upward with purple blooms on the ends. Each bloom appeared to be an average of 10 to 12 inches long. Would you happen know the name of this particular tree? We also saw the same tree while in New Mexico. I would appreciate your assistance.

ANSWER: You have perfectly described Vitex ?? the lilac of South Central Texas. It is available in pink and off-white. It is a very drought-tolerant shrub or small tree for the arid areas of the Southwest. However, it does not have the lilac fragrance for which the folks from the North long.

QUESTION: I have a question about a "fruit" that I found on one of my red oaks. I was examining the tree and found some small immature acorns. I also found a couple of round "nuts", about 1 inch in diameter. These "nuts" are spotted and have reddish/yellow stripes. I was not able to find any information in our tree book. What is this fruit? Is it a seed pod?

ANSWER: This sounds like an insect gall. Was it attached and/or surrounding a branch? If so, it is an insect gall which was the nest for young wasp-like insects which hatched last year. This is a common occurrence on oaks and does not damage the tree.