I think they do OK without being cared for so as long as it looks healthy I wouldn't worry.

A true Castor Bean (Ricinus communis) needs sun, ample water, warmth, and fertile soil. It grows fast and tall, and freezes at the first hint of frost.

False Castor Plant (Fatsia japonica) likes afternoon or filtered shade, moderate water, cool to moderately warm temps, and fast draining, moderately fertile soil. It grows fairly slowly, and can take moderate frost, though many were damaged this past winter in the UK.