I have never seen a crepe myrtle that doesn’t put up unwanted shoots. So, in essence at this time of the year, they need an additional pruning to remove new shoots. This helps keep the plant from becoming too dense if you have allowed it to be tree form. If you hacked them back, remove all the shoots but a couple on each cut branch. I really like to get them in the stage where you can simply pull them off at the base and avoid using pruners which can only cut them at the stem. This is especially true at the ground where shoots always seem to be appearing. If you can find a way to remove them so it gets the entire stem, it will not produce more this season in that spot. I really like pruning other shrubs in this same manner. I pull the soft stems off to maintain the shape of shrub without their looking pruned. Remember, with this procedure a quick jerk of the stem oftentimes is all you need. Today I was pruning a dogwood with a 3 foot long shoot this way, and it easily came off. Try this method, and I think you will like the results. By the way, it is a lot less work.