I grew this for 25 years in the old garden in a shady peat bed and it even came through our '82 winter, down to 0F one night and around 5F for weeks. It does pull itself down to about 1ft deep. I kept it moist all the time. It starts late, often not until June, and dies down again in Sept-Oct. Here it is in our new garden.

Jack Elliott (July 20, 2000) Kent UK min -8C

A nice size Arisaema candidissimum

Arnold (July 18, 2000)
New Jersey