How many times have you spotted the picture-perfect plant, ignored the little voice in your head that reminds you of your track record, and taken it home, only to find it sagging and flagging a few days later, destined for the compost heap? I imagine more than once. And how many times have you uttered the words, 'I always kill plants' when looking enviously at a living room jungle in an interiors magazine? But, has it ever occurred that the problem...