The only way I have found to grow Pinellia cordata successfully is in a pot, with best results when grown in a cool shady greenhouse. Then it can be a lovely foliage plant and the scent of the inflorescence is very attractive. It is treated as a monsoon plant, with a wet summer and dry winter (have just today put my pots into a dry shed). I do not know about "Don Jacob's form" or any others, the only clone I grow being "Roy Herold's", which, incidentally, is correctly named 'Yamazaki', after its originator, Hideo Yamazaki. I got my original tubercles from Mr Yamazaki, via the NARGS seed distribution in 1992, and by comparison with material from Roy Herold showed they were the same - as they should be, since his also came from Mr Yamazaki. The whole saga is written-up in: 2001. J.M. Grimshaw & P. Boyce. Pinellia cordata. Curtis's Botanical Magazine 18: 205-209. where the text is accompanied by a painting of 'Yamazaki' by Jenny Jowett. John Grimshaw Dr John M. Grimshaw Sycamore Cottage Colesbourne Nr Cheltenham Gloucestershire GL53 9NP Tel. 01242 870567