Answer #1 ·
Matt Heidke's Answer · For starters, I would wait until fall dormancy to reduce the shock of transplanting. The size of the root ball will depend on the size of the tree. For every inch of diameter per cane you would need at least 11" of root ball. So for example, if you have 5 canes and each one is 2" in diameter, you would need a 110" root ball. At 5 years old, I would say that it will take a professional tree moving company with heavy equipment to be able to dig the root ball and even heavier equipment to lift it once it is dug out.
Maybe it would be better to plant some new ones, here are some options for you:
https://www.togogarden.com/search/?q=crape+myrtle)