Q.what size container for a crepe myrtle
We do not want to plant our myrtle at this time, as we just cannot decide where we wan to plant it and we might want to take it with us when we move. We live in Atlanta, Georgia. What size container is needed in gallons and can we use a smart pot (soft sided fabric container)?
I would not recommend a soft sided container like you mention.
I nursery container would provide much better support and environment for you tree. Especially if you consider moving it with you to your new home.
Here is a link for you.