All small spurs of the crape myrtle flower, not just those at the highest points. Prune a crape myrtle to a single or multiple trunk of 3-5 strong stems. Use sharp tools because crape myrtle wood is dense. Remove crossing or rubbings branches that can cause wounds where insects and disease can easily enter the wood. Remove narrow-crotch angles.
Wider angles are stronger and provide better support and weather resistance.
Remove suckers at the base. Suckers are quick-growing shoots that drain a plant's resources. Aphids like to feed on suckers. Avoid pollarding your crape myrtle. You pollard a tree when you cut the tree's main branches back to its trunk.