I would do it gradually over a few years..If you cut it back too hard into the wood it may not recover...I moved mine a couple of years ago and cut the lower branches off. I planted a couple of smaller shrubs in front to hide the gap.....no-one knows...except me!!

Yes, I agree with Alice, there was one in the garden when we moved here and I pruned it hard...it didn't recover. I have a small one now which has been damaged by the cold weather, but I will lightly trim it in a few weeks time.

My experience is different from yours Janey - I cut back a 12 feet high and wide specimen 2 years ago in summer down to 5 x 5 feet, and it was fine. I suspect it's when you do it that counts - if you want to be radical with the pruning, don't do it till early June, but make sure you do it before July.

That's good to know Bamboo......they are such a beautiful shrub...shall leave it till June..........