That looks like a malva/mallow. Not sure if you can hack it back to keep it under control or not. I have a dwarf variety.....
Hi Elizabeth, You can treat your Mallow (Lavatera) in two ways. One would be to cut down completely one in three of the oldest branches in autumn after flowering finishes and remove any really weak growth at the same time. This would keep your plant on the tall side. The other way would be to cut the entire plant down to just above soil level in early spring, then feed the roots with a light fressing of rose fertiliser. This would keep the plant to about 5ft tall as it would make growth early in
Thanks Catztail, i only planted it last year and it sure grew big fast. The bee's love the flowers and my cat Poppy likes to hide under it too.