Q. We visited a neighborhood on the Fourth of July for an Independence Day Party. It was quite an area with lots of shade trees including pecans, live oaks, red oaks, cedar elms and mesquites. It surprised me that the trees did so well because it appeared the soil was just caliche and lawns had more horseherb than real grass. One of the most notable plants was a vine with a beautiful waxy yellow bloom that was about the same size as an esperanza bloom. I noticed that this vine had small leaves and small thorns on the stems. It was very aggressive in growing over fences and even into the trees. Do you know what the plant might be? Is it a vine worth growing for the flowers?
A. I think you are describing cat’s claw vine (Dolichandra unguis-cati). It is an exotic, invasive vine with a beautiful flower but not recommended because of its aggressive growth. It spreads from tree to tree and across the ground. The thorns are more sticky than sharp, but the vine is very hard to control. Apparently, it is used for home medical remedies. I guess it is ironic that I have used the product Remedy to control cat’s claw on fences.
Q. After 30 years it appears my yard has too much shade to support the Raleigh St Augustine lawn that did so well when it was first planted. What are my options? We tried thinning the crowns of the trees but that didn’t do the job, still too much shade. Will any of the new St Augustine or zoysia grasses have enough shade tolerance to survive?
A. Zoysia has less shade tolerance than St Augustine grass and new varieties of St Augustine that claim more shade tolerance have only slightly more, so I have to say that the answer is not zoysia or St Augustine grass. You can put up with a lawn that is not very thick and expect horseherb and other mowable weeds to fill the gaps or you can switch to shade tolerant groundcovers such as liriope, monkey grass, Asiatic jasmine, and dwarf ruellia. Check out some landscapes that use a mix of shade loving groundcovers, they can be very attractive and easy to care for.
Q. Our tomatoes did well this summer but now they have turned gray and have some webs. My guess is that it is spider mites. How can I treat them?
A. It is best just to pull the infested plants and plant new tomatoes for the fall. When you pull the infested plants minimize the spread of the mites. Put the old plants — mites and all — in a garbage sack so there are less mites in the garden to infest the new plants. There is no effective way to treat spider mite infested plants.
Q. Just about the time I conclude that my purple martins are finished with their houses this year they return for a few hours. When should we lower and clean out the houses?
A. All martin landlords are experiencing the same activity. First the young birds of the year fly off to assembly points and then the adults fly back and forth between the houses and an assembly point. It’s as if they are reviewing their options for next year before they leave for their wintering grounds in South America. They will be gone before Aug. 1. It is a good target date to lower and clean the houses.
Q. Our Whopper begonias have done well this spring, but they are a bit leggy. Can I prune them back?
A. Yes, cutting them back by 1/3 or even ½ is a good strategy. You can even root the pruned pieces for new plants if you need them.