Yeah, well I'd take that with a BIG grain of salt........unless you have seen with your own eyes these longtime growing zone 6 crape myrtle "trees".

Since you seem to always want to do whatever it is you are asking about regardless of what advice or alternate suggestions provided by some very experienced and knowledgeable gardeners, why even bother asking?? Spend your $$, plant your crape myrtle and see how tree-like it becomes.