I found your link on crape myrtles very helpful, but I am interested in doing some major pruning. The only problem is that I have searched all over the Internet and cannot find any information on what time of the year is the best time to prune. Any suggestions?
Crape myrtles bloom on new wood, which is growth produced during the current year. I prune mine in late winter or very early spring while the plant is still dormant. By pruning at this time I ensure maximum new growth for bloom and prevent clipping off the buds, which set about May.
There is quite a controversy over how to prune crape myrtles. It has been customary for many people to pollard their crape myrtles. Pollarding is the practice of lopping off the tops of a tree to the desired height. This causes the plant to flush with new growth. While this might be of use if you want all your crape myrtles to be of equal height, I find it a bit harsh looking particularly in winter when the stumps are bare. I prefer to prune my crape myrtles in a more natural fashion.
I begin by removing weak branches and spindly trunks. I also remove any interior trunks that are creating congestion and preventing airflow. If necessary I remove lower limbs to create more height or open up a view. Then I lightly prune the top to remove dead blooms or excessive growth. During the summer it is sometimes necessary to remove suckers, and shoots of new growth, that emerge from around the base of the tree. I also remove spent flowers to encourage more bloom.