Hi Gardengal ~
Check out The Arisaema Enthusiast Group website at:
http://botu07.bio.uu.nl
Look at the Forums at Arisaema-L ~ there is "tons" of information.
I never bought from this vender - cannot vouch for their
arisaemas.
Check out treasuredbotanicals.com. Good prices and the owner knows his plants!
Hope this helps...
~Gerry

Gardengal.....it depends on the species you are buying and the size of the tuber. Are they flowering size?? Most Arisaema can flower when the tuber is tiny, but the influorescence is far more impressive when the tuber has put on some size.....some can weigh a couple of pounds when mature, others are never more than a few ounces. Does the species you want prefer a lot of sun (candidssimum, consanguineum) or does it prefer some shade (many species). You will want to provide perfect drainage and make sure it is viable in your zone.....many, many species are not hardy in zone 5, but of course some are. You should do a bit of homework on these before buying as many species would not be considered easy. Best of luck :o) Dan