This is grown as an annual in the UK, so unless you have managed to keep one growing in a greenhouse you will need to sow new seed now.

Unless you're speaking of Fatsia japonica - this is often confused with Ricinus, so if yours has been outside all winter and is still alive, I'm willing to bet that's what it is. If so, you can prune out any dead or dying bits now, otherwise wait till end of April and then give it a good cut back if it needs it - take out major stems, if necessary, back to a leaf cluster.

...and if it is Fatsia and gets too tall or leggy, it responds well to having it's top chopped off! It will then resprout and be more bushy.