Mj, the Callas really love cooler weather. Once it starts to heat up they stop blooming and go completely dormant in the summer. But they come back up in the fall and bloom though winter. The trick is to get them started because most of the time the bulbs are offered in the spring, when mine have already been blooming for a month or two.
I have them in big pots and once they've died back I stick the pots in the coolest, driest spot I can find, shady side of the house under an overhang is good. If you remind me in the fall I'll share some bulbs to get you started at the right time.
I had some in my water garden, and the foliage stayed nice year 'round there, but they never bloomed.
