Hi Teri,
to All Things Plants!
The standard size
Crepe Myrtles (Lagerstroemia) can attain heights and widths of 20 to 30 feet or more and they would more than likely outgrow a container very quickly!
The Black Diamond varieties
http://garden.org/plants/searc... attain heights of 6 to 12 feet; I have a
Crepe Myrtle (Lagerstroemia 'Ebony Flame') that I bought last year growing in a container but my plan is to eventually put it in the ground.
There are Dwarf Varieties
http://garden.org/plants/searc... that require the same cultural conditions (sun, water etc.) as the standards but would work very well in containers.
You might like these interesting articles about Crepe Myrtles:
http://garden.org/ideas/view/d...
http://garden.org/ideas/view/d...