Can you tell me your golden rule of pruning flowering plants again? I always get that confused
Sure! As a general rule of thumb, for the interest of the flower, prune spring flowering trees and shrubs after they finish flowering (yes, there are exceptions to the rule, including fruit trees, etc). If the plants flower in the summer (after June 1), prune in the spring. If you are not concerned about the flowers on spring flowering plants, they can be pruned early spring before they leaf out.
When is the best time to cut back my Japanese yews and Boxwood?
Do your pruning before they leaf out in the spring, and don’t be too anxious to do it while it’s really cold. After they put out the first flush of new growth, and that ‘hardens off’, then feel free to come back with a light second pruning by hand to even-up and longer branches as needed.