Because crape myrtles bloom on new wood, some people think the trees need severe pruning to encourage new blooms, but this actually damages the structure of the trees and should not be done. Light pruning to remove crossing branches or enhance the natural shape, and removal of suckers are the only pruning that needs to be done regularly. For excellent, detailed info on crape myrtle pruning, check out this Facebook post by Bracy’s Nursery.
Crape myrtles do have a strong tendency to grow suckers, especially if they are damaged in any way, like if you hit a root with your lawn mower, or nick the trunk with a weedeater. Prune these vigorous shoots as close to the trunk (or root) as possible. If you have ever tried to remove a crape myrtle, you know that even after the stump is removed, a ring of new shoots often grows around where it used to be, because of the remaining roots. They are very difficult to get rid of!
Removal of the seedpods can encourage a longer flowering season during the summer—it’s the same as deadheading a perennial. Sure, it can be done, and it may encourage more blooming, but is it really worth it to you to deadhead an entire tree? Decide for yourself, but don’t feel like you have to do it just because your neighbor does.