Free Doctor.

Q: We live in Florida, and bought a dogwood from the Extension service on Arbor Day three years ago. Our tree is flourishing, with beautiful foliage, however we have never gotten one single flower. Do we need two trees to pollinate each other? Please help.

Shirley Noble, via e-mail

A: Dogwood flowers are "perfect," which means they have both male and female functions. One tree can do it all; a second tree is unneeded for reproduction,

I have checked several references, and find that the earliest age at which you can expect flowers on a dogwood tree (Cornus florida) is usually about 6 years. So, it sounds to me that good healthy green foliage right now is the best sign you can have to assure you are on the right course for future floral displays.

Q: Help! The deer are eating my cedar trees. I now have them covered, soon they will be too big to cover or transplant. Would pine trees offer a solution to my problem? I'm looking for a tree that's not very tall or wide, but still offers a wind break.

John, Rome, New York 

A: The best advice for you is to try to keep the deer away for a few years until the trees grow high enough so the deer can no longer eat them. Easy to say, but tough to do. There are some deer repellents that can be sprayed on; I don't know how often treatment must be renewed. You might also try keeping the trees fenced until they get tall.

Try contacting the New York Forestry Department, or your Cooperative Extension agent for advice along these lines. They might be able to recommend some less-tempting species to plant in place of the cedar. The foresters can also recommend suitable trees for windbreaks in your area.

Q: I have several beautiful, old (maybe 60-70 years) apple trees. They bloom every year and produce delicious apples. Unfortunately, they all have large hollow spaces in their trunks or on large branches. This makes them weak, and two have already blown over in a storm. I have heard that you can fill these hollows with something--cement?--to make the trunk stronger, and this won't affect the life of the tree. Can you advise? What could I fill the trunk with, and how should I do it, etc.?

Linda Morrison, Downingtown, PA

A: I am afraid my advice isn't very positive. I, too, have two old apple trees, one of which is on its last legs. Trees are living entities, and like us, have frailties and a finite life span.

Filling hollows is no longer recommended. Recent research has shown that cement really just seals moisture in, and thus, promotes a faster rate of internal rot. Earlier tree "surgeons" used chisels to try to remove the rotted wood, but were never successful, as the decay extends well beyond the hollow. In my opinion, the best approach to dealing with aging trees is to recognize that they will be gone in a few years and plant some replacements now. By giving some thought to placement, you can start young trees that will be large enough to provide the amenities of the older trees as those die off. (This is my personal approach, too.)

Apple and other fruit trees are usually pruned heavily. When done improperly, this increases the chances of rot entering the trees' interior wood. Careful pruning of your young trees will probably prevent a lot of future decay. There are several references by Dr. Alex Shigo that illustrate proper pruning.