It has been my experience that these offshoots that come up from the roots tend to naturally become tall before they Y so if you are looking for tree-shaped, I would be inclined to let it grow on. Put a pot ( a gallon pot) around the base of it on ground level, fill it with soil for the summer and keep it damp and it will be rooted on it's own system of roots when it comes time to bring them in and then seperate it from the mother plant. ( JMHO)
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