According to the article linked below, they are only hardy to zone 7 and come in various shades of green, pink, purple, yellow, and orange.

If you are looking for spring color, you might want to consider other hardier bulbs.

Sue

Here is a link that might be useful: Growing calla lilies

Calla Lilies are beautiful, but in our northern zones, should be planted in spring. I planted a pot of them this past spring, and they were lovely! They're beginning to die back now, so I'll lift the bulbs/corms and store them for the winter. I also planted some Glads and Cannas in containers, and they were nice.

If you have your heart set on bulbs in containers, I'd wait until spring to plant them. I'd use bulb or corm types that are meant for spring planting, like the Calla Lilies. I would be afraid that any bulbs planted in containers would not make it over winter, unless protected very well. Our winters can be brutal.

What you CAN do, is plant spring blooming bulbs in your containers, and then store those containers in an unheated garage or shed so they get the cold treatment they require, without getting too much exposure. Then, when you see growth in early spring, move the planters outside.

I've never done that, but I have planted Hyacinths in pots and refrigerated them for their specific length of cold treatment. They bloomed fine once brought indoors.

I'm sort of "writing out loud", here, as it were... so, I'm not even sure containers can be planted with spring blooming tulips, or the like, and stored in a garage over winter... although, I don't see why not. In fact, I may try that very thing! I have a pair of very large patio pots that would look great with spring blooming bulbs in them... but I would be afraid our winters might be too brutal to leave the pots outside without protecting them. Parrot Tulips would look splendid! And as they started to fade, I could plant some annuals in between them...

Colorblends is a good place to buy bulbs...so is John Scheeper's, Easytogrowbulbs, Willow Creek Gardens, Brent & Becky's... and there are lots more! Google "Fall Planted Bulbs" or "Spring Blooming Bulbs", and you'll come up with tons of places to look for great bulbs!

Good Luck!

Only the pure white callas (Zantedeschia aethiopica) are considered hardy and then only to zone 7 at the lowest. These are the only species that overwinter successfull here in my zone 8 climate. The colored callas are hybrids and are grown as non-hardy (annual) summer bulbs. They should be planted in spring then lifted after the first frost knocks back the foliage and stored for winter.