I have 6 crape (crepe) myrtle shrubs that I planted along my driveway. This is the first time in three years that they have bloomed, and they bloomed late (In September in zone 5). My question is, do they always bloom this late in this area, and should the plants be cut back for the winter?? If anyone in this area has experience with this plant, I would appreciate any information they could share. Thanks.

Here's a site about Crepe Myrtles.

http://virtual.clemson.edu/groups/bcd/crepemyrtle/crepehome.htm

Check out the fact sheet section for pruning info.

My neighbor has a large crepe myrtle that's been in his yard for years. He has never has pruned it, it blooms after Labor Day every year,it is gorgeous.