How much can I trim a barberry back? They have really gotten to big and I would like to trim them way down but want them to come back nice in the spring.
Barberry can take hard pruning. It's possible to cut it all down to several inches: it will come back. A less drastic approach is to cut 1/3 of the oldest (widest) branches to the ground every year. This keeps it looking good and helps contain how tall it grows. Additional trimming to maintain desired height can be done anytime.