Kent, United Kingdom

I have six beautifully coloured Celmetis which I bought at the Chelsea flower show about four years ago. They are all different, lost the name tags, but they are oustanding. They are growing over the side of the garage and all in full bloom when last week the one on the end suddenly over a couple of days died completely. All the leaves went brown and dried up and the plant died as if overnight. Any idea what happened and what can I do to protect the rest of these magnificent Celmatis.

• 13 Jun, 2010