Q: I have rows of large (30-40 ft tall) Leyland Cypress trees surrounding a pool which I have been “shaving/pruning” for 14 years. They have become very top heavy and have started to splinter/lean to a side. Wanting to get a few more years from them, I went ahead and topped them at about 20 ft. Will the lack demand for nutrients at the now-missing top of the tree benefit the remaining base of the tree?
A: I don’t think there will be any great benefit from extra nutrients. There might be benefit from extra water supplied to the lower part of the tree. Leyland cypress don’t grow big root systems. That’s why they get diseases so often.
You were smart to top them because they often fall over from being top-heavy.