Q: Should I cut back the tops of my tomato plants to encourage fruit production? Every year it seems they keep growing and growing but don't produce the amount of fruit I would like.
A: You can cut the tops off. However, they normally grow tall due to lack of sunlight. Limited bloom production is also the result of lack of light. Consequently, the new growth that follows your pruning will still grow toward the light.
Also, the pruning will stimulate more vegetative growth rather than bloom production. Ultimately, it may be better to look for a place in the yard that gets six to eight hours of direct sunlight to increase your tomato production.
Q: What kind of material can be used to fill a 2- to 3-inch diameter hole in a dogwood tree where a branch once grew? The tree is otherwise healthy, but I want to fill the gap while the healing bark around the hole is growing over. Is cement OK? Or should I use something else?
A: Years ago we did recommend cement mix to fill those cavities. However, it was very rigid and tended to crack as the tree grew. Later it became more common to fill a cavity like that with asphalt patching mix. It had more flexibility and still served to give some strength to the hole as well as keeping water out.
More recently, I've seen recommendations to use a foam insulation material called Great Stuff to fill those holes. The foam expands to fill the cavity as it dries. There is nothing toxic in the foam that would injure the tree, and it's waterproof. Just be sure to stop at the back side of the healing cambium so it can easily grow over the material.
Q: I have a mature mimosa tree with a branch that seemed to die on one side. We cut it off, and there was a very dark area and possibly a hole. Now the trunk is wet, and just above the wet area sap seems to be leaking. Do you believe the tree is diseased? Is there anything that can be done to help it?
A: The oozing sounds typical of a bacterial infection called slime flux. However, mimosa is very prone to a disease called mimosa wilt. It normally attacks mature trees that appear otherwise healthy.
My suggestion would be to have a certified arborist examine it or take a sample to your county extension office for diagnosis. If it is wilt, there is no treatment, and you would probably want to replace the tree with another type. However, I think you need to get a confirmed diagnosis before getting rid of the tree.
If you decide to take a sample to the extension office, call first for details on the type of sample they would need.
Q: A few years ago, the Richmond Times-Dispatch had an article about a man who had thousands of daylilies and will only sell them when they are blooming. I'd like to visit his garden, but I've lost track of where he's located. Can you help?
A: I don't remember that article and am not aware of that particular grower. However, we have a wonderful daylily society in central Virginia, the Richmond Area Daylily Society (RADS). I'm sure they will be able to help you. You'll also find a number of other really good growers through the society. You can find them at www.myrads.com.