Still safe to feed the roses

Gardeners wrote to me with some surprising questions and observations over the last couple weeks. These three are good examples.

Q: I have a few questions about caring for my roses at this time. We fed them on June 9. How late can they be fed again this season? My Knockout roses are about four and a half feet tall. How far back should I prune them? Any help in these matters would be welcomed.

— R.V., Lynchburg

Answer:

You could safely use rose fertilizer as late as the end of August; just try to avoid putting on too much of it. Knockout roses are cut back in early spring. Right now all they need is deadheading, and that can involve cutting out stems up to a foot long.

Q: Regarding your Aug. 17 column about the rotting tomatoes, it actually sounds like the person has a stinkbug or squash bug problem in the garden. I have seen this happen to several tomatoes this year, and it is different from regular bottom rot. The stinkbugs feed on the bottom of the tomato. One or two feedings will result in a starburst pattern at the point of insertion of its beak. Multiple feedings will liquefy the inside of the tomato, while leaving the skin basically intact. It doesn’t turn black on the bottom of the tomato for several days. The bodies of the stinkbugs are a pale green (at least right now) and they blend in with the green tomatoes they feed on, because they are feeding upside down. I have spent entirely too much time studying and battling stinkbugs and squash bugs for the last two summers! I can also tell you that two tablespoons of dish soap in a quart of water is very effective for killing them (stinkbugs float … squash bugs sink).

— E.K., Amherst

Answer:

Thank you for the input. I also spend too much time on these bugs.

Q: I was wondering if you could answer a question for me. We have lived in Lynchburg on and off since 1992. The strangest practice I have seen around here is the scalping of trees. Isn’t this a bad idea? Why do people do it? I would think it opens up many areas on the trees to bugs and disease. It also makes the yards look ugly and I’m sure it must lower the property values. We have lived in a few other states and this is the only one where this stupid thing is done.

— C.K., Lynchburg

Answer:

The scalping you mentioned is also called topping, dehorning and hat-racking. It is a very bad idea. People get their trees topped for various reasons, and the trees involved immediately start to rot and become a serious safety hazard. Topping is a form of arboricultural malpractice and it has been common in some parts of the country for generations. It is usually better to cut down a tree than it is to top it.

Davis is a retired Lynchburg Extension agent. He can be reached at dodavis2@vt.edu.