I've got/had/soon will not have? a rather lovely pot-grown regal pelargonium which has slowly lost all its older leaves - turning brown and drying up. No obvious spots or signs of fungus can be seen on the dying leaves and the plant seems happy enough to try and sprout new leaves and flowers, but as I seem to remember this happening on a smaller scale last year, I'd like to be able to identify (and prevent!) the cause. A normal 'ol geranium only a couple of feet away seems fine... Any ideas?

Thanks for this link. I'm still not sure what the problem is, but I reckon that I'll just take the plant out of the pot and see whether that works...

Cheers,
Clare