Q: I have a magnolia tree that was on the lot when our house was built. It probably suffered root damage when they cleared the lot. Can I top the tree to stimulate growth? Are there any fertilziers that would help?
A: I’m not sure what you mean by topping. If you mean just taking out the dead wood, that’s OK. But typically topping refers to heading back or cutting the tops or growing points out of a tree. This is a terrible thing to do to a tree. Instead of solving a problem, long-term, you create a much bigger problem–a hazard tree with a lot of die back in the top. If you’re talking about only removing what is already dead, that’s a completely different ballgame and can be done. Fertilizing a declining or injured tree can cause more damage than good.
If the tree is having difficulty supporting the growth it has, the only thing you’re going to do in fertilizing it, is to cause it to produce more growth that it can’t support. The exception to this is if you’ve taken a soil sample and the results show that certain elements are deficient and you select a fertilizer based on what’s missing. Otherwise, fertilizing for the sake of fertilizing is very likely to cause more problems. Here are websites with additional information: