Our crepe myrtles have not leafed out or bloomed this year. We did have a late freeze. Trees are about 12 years old and have bloomed every year. Trunks are about 2-1/2 to 4 inches in diameter. Branches, both small and large, snap and seem dead but I have new growth sprouts from the bottom and some as high as three feet from ground. Should I trim back to the new growth and let them try to recover?