How cool!!! Don't you love surprises like that? Have you ever grown calla lillies from seed? I saved a bunch of seeds one year but never planted them . . . maybe they are more versatile plants than we think, and perhaps I'll go for it after having read about your experience. Donna

I'm a zone warmer than you, but they definitely can handle cooler zones than 9. I have some that have been in the ground for years in unprotected areas. They multiply like crazy. The only ones that have not come back for me were the black ones, darn! Pretty easy from seed too, but young seedlings are more sensitive to the cold than mature bulbs. I have one clump that even reseeded itself, but not many of the seedlings made it through the winter, even though they were protected a bit.
Once they are up in the spring, it doesn't take long before they bloom. Mine have bloomed and are now spent.

We are in south western PA (z6)& my mom has calla lilies against her house in front. They have been coming back for years now & have multiplied like crazy. "They" say they won't grow back here, but hers are just beautiful, not sure if it is the warmth from the bricks on the house or what,she just cuts them back in the fall,I have seen others with them too, some out in the open & they are back there every year, i guess you never know til you try!
Holly

Hello Calla lvers
I decided to check out the bulb forum and chanced on this exchange. I can help out with some wondering with my cut & paste from the Aroid Forum - Here it is along with the respective dates.

Tue, May 29, 07

Thought I would inform Calla Lily lovers in cold climates of a species/form that will grow where winters can be cold. I live outside of Buffalo, NY (zone 6) and planted Z. aetheopica 'Crowborough' form. It survived the winter of 2006/07 and is beginning to put on good healthy vigorus growth. I was very casual about protecting it as our winter began extremely mild. That changed in the middle of January, however it still survived! We get snow cover that acts as insulation.
I bought it from Arrowhead Alpines. It has not bloomed yet, but possibly this summer.

Wed, Jul 18, 07 Update on Zantedeschia aethiopica 'Crowborough'.
My plant is growing quite vigorously and looks very healthy.
No bloom as of yet, I think it may need to mature. I checked it as of 11:44AM, 7/18/07
I planted out in a south west exposure in a well drained area of my yard.
I water it occasionally as it has been a dry year. I planted it last year and casually protected it. Since our winter was quite harsh from mid January to April and it is growing good, I would say it is hardy to Zone 6 which I am.
I bought this from Arrowhead Alpines. This is reputed to be the hardiest Z. aethiopica form according to my research.
I recommend it.

August 13 - update:
It is growing despite our dry conditions here in the Buffalo, NY area. No flowers as of this date. This winter, I shall mulch it better than laste winter. It looks really good and grew back this spring despite looking like cooked spinach due to winter!

Our calla lilies survive the NYC air, as we live in the backdrop of the Manhattan skyline. Started with 25 calla bulbs-all planted in containers-instruction suggested to bring indoors when temps reach 40 degrees. We trim them back-keep dormant through April-start watering-bring outdoors in May, depending on temperature. Near the end of the summer, the flower and leaves sag-cut off flower from stem-inside the flower there will be a bulb forming. Dry out bulbs and plant indoors in April start watering process, leaves will form-my second year, we had 50 callas-2-4 feet high. Strangers were walking up to my home to get a look at the flowers-do not handle flowers!They are eyecandy in a garden! If you can not find plant food, in one quart of water add 2-3 teaspoons of 7UP or Sprite-citric acid is a common ingredient in some plant foods. Good Luck fellow gardeners