I grow most of mine in pots for the reasons you describe, poor drainage in particular. It also makes it easy to move those which go dormant in midsummer here to less prominent locations. The technique used depends on the species.

Those which are prone to early growth (A. ringens, sikokianum, nepenthoides, and mayerberae, for instance), are planted in 12" clay pots which are stored almost dry in my unheated garage for the winter. Pots of this size can be moved in and out as the weather moderates in early spring. I do find it best to repot anually (once the plants go dormant), since the hungry plants tend to exhaust the compost in which they're growing. I plant achimenes rhizomes (smaller impatiens would work as well) with the bulbs as an "indicator species" - I only water these pots when those plants show signs of wilting. Once warm weather arrives, these pots are plunged into a much larger pot (like a half barrel) and surrounded by other plants. After this, the arisaema pots themselves are not watered, but the larger pot is - enough water is absorbed through the clay pot to keep the arisamas moist, but not soggy enough to rot.
In fall, I repot and start over (this is why I like the achimenes as companions - they spend the winter as dormant tubers as well).

Later growing species, such as consanguineum, candidissimum, heterophyllum, and fargesii are stored in smaller pots of compost and kept almost dry throughout the winter. Usually, by the time they show signs of growth, it's safe to plant them directly into large outdoor containers (again, the half barrel is a great size and shape for this). I don't worry about double potting these species.

A. triphyllum seeds itself around my garden and is native here, so I don't worry about potting that, unless I'm growing seedlings. A. speciosum (sp?) is of questionable hardiness and has a rhizome that ranges too far to be dug and stored every winter, so I grow that in a raised bed under a layer of mulch, and it seems to do fine. One of my favorite plant combos this spring has been seeing the narrow red edging on the leaves of this species echoing the color of the Spigelia marilandica blooms coming up among them in the planting bed.

Hope this helps!

I, too, am wondering where to plant my arisaema that was given to me. I believe it's triphyllum.

bubba62, I see that you said yours seeds around the garden. May I ask where you live? I'm in zone 7b in eastern North Carolina with very sandy soil. I'm not sure it will maintain enough moisture for the plants to survive. I'd appreciate it if you could tell me if you think it will do ok in the ground or if I need to pot it up? If I need to pot it, what should I use for potting medium? Thanks so much in advance.

Pam