I thought they had a dormancy cycle, but maybe not if grown indoors? Someone will probably respond, and I'd be interested to know. I know they go dormant if grown outdoors, and they should be hardy in the ground in your zone, but wait until after last frost date in spring to plant out. I really want to get the giant Z. aethiopica from PD this spring.

Susan

To let them go dry and dormant for at least 8 weeks after flowering is the most reliable way to get them to bloom again. You can also let them stay dormant much longer , at least 6 months, and restart them to flower for holidays and special occaisions. It will vary according to conditions and may take a little practice, but figure about 10-12 weeks from potting up to flowering.

I started pots of aethiopica and albomaculata each of the first three weekends in October to make sure I had plenty for Christmas. They all look good now. With a little snipping of spent blooms potted plants will be nice for about 3 weeks inside. Not as long outside in hot weather.

Keiko

I was asked to do a July wedding and the bride wanted to do Callas. I knew my callas would not be blooming then so I went to the local greenhouses. All of them had put their callas into dormancy and none would be blooming then either. I went to the internet and found one that still had them in bloom but if I had waited just two days later they would have been asleep, too. That was a California grower by the way.
I was told our local greenhouses pot up the tubers in February.
Indoor callas become outdoor callas very easily. The bulb/tuber of an indoor calla often dies from lack of proper dormancy requirements. Placed outside, in the ground, they get larger. If you don't have a cooler for them, you might try putting the pot in the ground and digging it up when it begins to grow again. Sandy

Callas are really much more temporate than tropicals as many believe.

If you drove down CA101 and threw them out the window they would become invasive and flower reliably in late winter or early spring when it's still raining.

Places like Dallas or Ft. Wayne they need a lot more empathy.

Keiko

I forgot to mention Keiko2's Info about the timing is just right. Since I was asked in late May it would have been impossible to get flowers for a July 5th wedding not to mention the impossibility of getting bulbs that had been in a cooler for the last several months. Thank you, Keiko. Sandy