Q: I have large Leyland cypresses which I would like to prune. The trees are twenty feet wide and thirty feet tall. I want to prune back three feet at the bottom of the trees all the way around. But if I prune this much, I get into the older parts of the limbs that do not have much green growth on them. It is possible to prune like this without harming the trees?

A: This could be very problematic. Leyland cypress does not regenerate much green foliage from the brown parts of a limb. I fear you’ll have a piebald brown and green tree when you’re finished. It is possible to prune Leyland cypress to reduce size, but only if cuts are made beyond a green shoot, leaving green foliage behind to resprout. This kind of pruning is best performed in mid-March, right before new growth begins on landscape plants.