I just planted my very first crepe myrtle yesterday and have been reading a good bit on them. I found a nice link to a website at Clemson University that has diagrams, tips, and even a video to view. I hope this helps.

Here is a link that might be useful: Crepe Myrtle Pruning tips

Never top it, please don't follow that practice that unfortunately has become common. Lagerstromias are technically shrubs, with many branches from the base. Just select 5 or so well formed branches, cut the rest away at the base. This will need to be done periodically. If not, it will continue to send up new branches, thickening and widening the entire plant over time to a massive thicket. feenix's site linked above shows a good diagram of the proper pruning.

Hi, I found this site today to help with crape myrtle care. It has a pruning section in it. hope it helps, joela

Here is a link that might be useful: crape myrtle care