Topping is a destructive practice with any species of tree. Crapemyrtle can tolerate annual topping but there are zero benefits associated with the practice. Size reduction can be achieved but to the detriment of flower production, winter form and other aesthetics. In addition, plants are left to cope with substantial injury and decay recovery. Crapemyrtle is a diverse species, with varieties and cultivars that grow naturally into numerous sizes, shapes and colors. If your planting area dictates a small crapemyrtle, you can plant a crapemyrtle that stays small. If you have a large space to fill then there's a large crapemyrtle out there that fits the bill. Crapemyrtles properly planted in full sun, maintained as they should be and allowed to grow to their natural size tend to be some of the most beautiful ornamental trees in the landscape. They are a "total package" tree, possessing an assortment of aesthetic and durability qualities. It's unfortunate that many people still miss out on all the wonderful characteristics this species has to offer when it's allowed to just be itself!