Dear Neil: We have an aerobic septic system, and we've had trouble with roots growing into it. There were three yaupon hollies about 5 feet from it, and I had them removed. I also have two mountain laurels on the other side, about 3 feet from it. Do you think their roots will cause a problem, and if so, can I move them to another location? I've had them about 10 years.
A. You might want to discuss this with the company that did the original installation or the person who services the system each year. There should be a way to install a root barrier between plants and the system. Better yet, there may be a way to open the tank enough to remove any roots that have penetrated it. Your problem is unusual. There may be a problem within the system itself or the connecting pipes that is allowing this to happen. You need the help of a professional in that field. Hopefully you can find a way to solve the problem without having to move large mountain laurels. That would be a laborious task.
Dear Neil: My 419 bermuda lawn has suffered serious trampling from the neighborhood kids. They now play in a park nearby, and I want to replace my lawn with new turf and build up the thin underlying soil while I'm at it. When should I do it, and what type of soil should I spread? Do I have to remove the old grass first?
A. This is a big task that is best accomplished in April or May. You do need to remove the old grass first. The easiest way would be to spray with Round Up or one of the other glyphosate herbicides. They will kill the old bermuda without contaminating the soil. After two weeks you can rototill and rake out the old debris, then bring in your new loam topsoil. Your local nurseryman can suggest the best source, or you can work with a landscape contractor to do the entire job for you. They will know sources of "safe" soil, that is, soil that is free of nutsedge and other potential problems. After you get the new soil in place, tilled and raked smooth, you can plant your new sod. Let your local sod yard work with you on selecting the best type for your needs. In fact, it's probably a good idea to involve them in this entire process from the outset. If you decide to choose another type of bermuda, you must be completely sure that the remnants of the 419 have all been eliminated.
Dear Neil: How can I kill ajuga that has jumped from my beds into my St. Augustine without hurting the grass?
A. Apply a broadleafed weedkiller spray containing 2,4-d with a pump sprayer directly to the ajuga at a time when it is growing very actively. April or May would be ideal. Keep the spray away from groundcovers, low shrubs, flowers and other non-grassy (broadleafed) plants.
Dear Neil: I have a non-bearing grapevine. I grow it for its leaves, which I use in cooking. Most years I don't prune it, but now it's grown too tall and wild. When should it be pruned?
A. Grape pruning, whether to tidy your plant or to keep a fruiting type in peak production, is done in late January or early February. You may be surprised by the improved quality of the foliage you get after the pruning.
Dear Neil: We have a young pecan (I don't remember the variety name) with very good pecans. Could we graft a Burkett onto one side?
A. You probably could, but you shouldn't. Burkett is a very old variety (100 years old), and it is not nearly as dependable a pecan variety as many of the newer hybrids. What you have is probably better. Plus, you'd have a mismatch of the two halves of your tree. That could lead to problems.
Dear Neil: What should we do with our sprinkler system during the winter? Let it run, or turn it off and run it only occasionally? This is a major issue in our house.
A. You should either invest in a "smart" controller that will monitor watering needs and only allow the system to run as it's needed, or you should leave it in the "manual" mode and turn it on only as you see the need. This is a great way to conserve our state's natural resource.
• If you'd like Neil Sperry's help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at firstname.lastname@example.org.