Prune off whatever you want to get the aesthetic look you're interested in. I've done this many times with many species and never had a problem. I start at the bottom, work my way up, and step back occasionally to check out my work. Don't worry...it will not hurt the clump in any way.

Great, thank you. The canes are too attractive to leave covered up. I read that as they mature the canes will not have the lower branches. In one year and a few months of planting (3) 2 foot tall plants, the clumps are very thick, probably 25 or so canes from each plant and 25' already. The canes emerged quickly and all year, maybe due to our warm weather down here. I chose canes that were already tall for the divisions that I dug up and moved and the branches are opening at the tops, so it looks as though there was little set-back if any. I'm glad to start trimming the lower branches now. Thanks again, Joss