I planted Thryallis this spring and it shot up fast and is doing well for the most part. 75% is full and plush, the remainder is leggy and thin. Can I cut these back now to promote fuller growth or do I need to wait until winter months?
What did you end up doing- out of curiosity? Seems the leggy part is from shaded areas, if that is why the legginess, pruning isn't apt to help, but if it's hidden, you might experiment with a lop or two since it doesn't appear to die until long term cold weather