Q.Want to transplant a young crepe myrtle from my yard to a pot.
Don’t know the variety except that it is white but it is not a Natchez. The tree has been planted about a year and is about 7 feet in height. I live in south Louisiana, not sure of zone. The tree has to be dug up and I don’t want to discard so decided to put in a pot. I purchased a large round pot, 21” in diameter and 18” tall.
My questions: Will it grow according to the container size and then stop? I really don’t mind it being much bigger than it is. If not, would pruning keep it stable or will it eventually burst out of the pot? Will it bloom in the pot? Would it require any special maintenance other than pruning?

Certified GKH Gardening Expert
It looks lovely where it is. Here's an article that will help you move it to a pot. I don't think your pot is big enough, however, to accommodate the root ball. Once you have it established in the pot, when it becomes rootbound and you don't want to go up another pot size, you can try root pruning if it isn't too tall. If it isn't a dwarf crape myrtle you may have issues. If it begins to lose leaves and you see signs that it isn't thriving, you may want to consider repotting or getting it into the ground.
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/transplanting-crepe-myrtle-trees.htm