Keep the lower limbs pruned off. It will continue to grow up and then make a canopy. Don't expect them to get much over 15 to 20 feet tall, I've not seen any taller than that so expect that might be their upper limit. Do expect lots of viable seeds coming up and they will even sprout from the roots on occasion. Here in USDA Zone 9b they can be almost as invasive as the Chinese Tallow trees. George Njdix@aol.com wrote: > > What is the best way to train a Rose of Sharon bush into a tree with one > trunk?