Q: I have thirty-year-old red tip photinias that are twenty five feet tall. I’d like to “down size” them. Am I correct that this should be done only in early spring prior to new growth? And is it permissible to take them down more than 1/3 in height a year? I’d like to get them to about 8 feet.
A: My usual advice on pruning photinia is to do it in summer, which results in fewer disease-prone young leaves. But if you want to severely reduce the size of a big photinia, the best time to do it is in early spring, perhaps late February. This will give plenty of new growth but it will come with the necessity of spraying it with fungicide to prevent leaf spot disease. Apply fungicide from budbreak until June. In succeeding years, prune in the dry part of summer to keep the shrubs in bounds and leaf spot free.