They are very tuff!. My mother had a couple out near the curve in front of her house and the city would come around every three years and trim the tops of the trees to keep them out of the power lines. After that they started suckering real bad, the city tree trimmers ruined the trees in my opinion. I swore if I ever had a Crepe Myrtle I would never trim it. Just saying, IMO.
Karen, is yours a dwarf? I have a white dwarf in my corner garden, it's a slow grower but gets prettier every year.