Colchicum (often falsely called autumn crocus, which is a very different bulb) are beautiful autumn-flowering bulbs. And they’re very hardy, from USDA hardiness zones 4 to 10, even zone 3 if the sector enjoys good snow cover.
The spectacular flowers do indeed resemble giant crocuses, although they belong to their own botanical family, the Colchicaceae. (Crocuses belong to the Iridaceae family.)
Curiously, most colchicums flower in the fall, emerging from the ground without foliage, thus creating a particularly stunning effect.
The leaves only appear the following spring, at the same time as the leaves of other hardy bulbs. Then they disappear in the summer.
No particular care is needed. Just plant them in sun or partial shade in well drained soil and let them grow. Over time, the colony will multiply and you can divide them to fill your flowerbeds with more of these beautiful flowers.
Colchicums: Easy to Grow, Somewhat Harder to Find
You won’t find colchicums in most garden centers, however, as they haven’t the faintest idea how to handle these bulbs. You see, you need to plant colchicums almost as soon as they arrive in the store, either that, or keep them in cold storage, otherwise the start to bloom on the shelf. Yes, they’ll bloom with no soil at all! So essentially, colchicums only have a shelf life of a week or so. After that, they’ll start to bloom, all on their own!
My local garden center ordered some once and just put them out on display at room temperature with the other bulbs. While they had from September to November to sell their tulips and narcissus bulbs, the two-week window they had to sell colchicum bulbs wasn’t enough and most remained unsold. Nothing looks less appetizing than a cochicum bulb (corm) shrinking after it has bloomed!
As a result of that experience, they never offered colchicums again.
Mail Ordering Colchicums is the Way to Go
The logical way of obtaining colchium bulbs is to order them by mail. Bulb growers know just when to ship them. They’ll mail them to you at just the right time so you can plant them and watch them bloom only a week or so later.
Gardeners from other countries: check the Internet for a bulb source near you.
Don’t Eat ‘Em
Colchicums are poisonous, so don’t eat them. But then, don’t eat any plant unless you know it safe to eat. Even tomato, potato and rhubarb plants can poison you if you eat the wrong part.