I actually have two questions. First: How deep do I have to go to control bamboo from spreading? Second: When is the best time to prune river birches (they are only three years old) and crape myrtles?
Baltimore County Maryland
If you are using a barrier to control bamboo, the trench should be dug to at least 3'. The best time to prune deciduous trees is in late summer. Crape myrtles bloom on new wood. The best time to prune them is in late spring before they leaf out.