Crazy for Colchicum

When most people think of bulbs, they think of spring-flowering plants such as tulips and Narcissus, or maybe summer ones such as Allium or lilies. One often-forgotten season is fall, even though fall is prime time for one of the most carefree and surprising bulbs of all, Colchicum.

PHOTO: Colchicum 'Waterlily'
Colchicum ‘Waterlily’

Commonly known as autumn crocus or meadow saffron (although it is important to note that they are neither saffron nor a crocus and are poisonous if ingested), these lovely ephemerals are jewels in the fall garden.

Get your own Colchicum bulbs (and more!) at the Fall Bulb Festival, October 4 – 6.

PHOTO: Colchicum cilicicum
Colchicum cilicicum

PHOTO: Colchicum autumnale 'Album'
Colchicum autumnale ‘Album’

Although they’re commonly referred to as a bulb, Colchicum are not a true bulb, but are corms, much like Gladiolus and Freesia. Colchicum have an unusual habit of growing their foliage in the spring (just like most plants), but then instead of flowering, they go dormant for several months. Then, seemingly out of nowhere, they send up dozens of purple, pink, white, or checkerboard flowers just as the rest of the garden is getting ready for fall.

Colchicum prefer a location with full sun until midspring and grow best in a location with well-drained soil that does not stay wet during the summer dormant period. This makes them ideal for planting under trees, where other plants might not compete as well with the roots. The bulbs should always be planted two to three times deeper than the bulb is tall to help ensure a long life.

To appreciate these intricate flowers, plant Colchicum in large groups near the front of a border. Because the foliage remains green until early summer, it is best to either plant them in an area with a groundcover, or to choose a low-growing annual to plant over them once the foliage has gone dormant for the season. This not only hides the bare ground, but also provides some support to help keep the flowers upright.

Look for Colchicum at the Chicago Botanic Garden beginning in mid-September and continuing through October. The Bulb and Home Landscape Gardens have the best displays of this fall beauty.

PHOTO: Colchicum 'Violet Queen'
Colchicum ‘Violet Queen’
PHOTO: The Home Landscape Garden, dotted with clusters of Colchicum 'Violet Queen'
A large planting of Colchicum ‘Violet Queen’ in the Home Landscape Garden

©2013 Chicago Botanic Garden and

An Autumn Surprise

Crocus in autumn? No, it’s colchicum, a fall-flowering corm that holds quite a few surprises.

Every garden should hold a few surprises.

In fall, the Landscape Gardens deliver a good one: bright lavender patches of Colchicum, commonly known as autumn crocus or, less commonly, meadow saffron. Popping up suddenly through the groundcover, the flowers can stop visitors—and bloggers—in their tracks. With the current streak of balmy weather, the colchicum seem to be lasting even longer this year, begging a deeper look into the surprises that this bulb (actually a corm) holds up its leaves.

Surprise #1: It’s not a crocus.

Short, goblet-shaped flowers and spring-like color cause the confusion between colchicum and crocus, but there’s an easy way to tell them apart: count the long stamens in the center of the flower. Six stamens? It’s a colchicum. Only three? It’s a crocus. Colchicum’s flowers are much larger, too, and its leaves are long and strappy, rather than short and grassy.

Surprise #2: Spring leaves, fall flowers.

Expectations run high in spring, as colchicum’s wide leaves emerge, flowerless, to do their work, pulling sunlight’s energy into the corm underground. Then the leaves retreat for the summer. Time passes…and then the surprise comes, as clumps of flowers, leafless, emerge from the same spot in fall, a pleasing reminder that gardening is powered by patience.

Surprise #3: It’s not the source of saffron.

Although colchicum’s common name is “meadow saffron,” it doesn’t produce the flavorful red stamens of kitchen/culinary fame—that distinction belongs to Crocus sativus, a true crocus that also blooms in fall (along with its leaves—you can see why it gets so confusing). Unlike that crocus, colchicum has less showy stamens that cannot be eaten because…

Surprise #4: It’s poisonous.

The whole plant is: flowers, leaves, stamens, everything. Site it accordingly in your yard.

This weekend, three beautiful colchicum varieties will be sold at the Fall Bulb Festival—‘Lilac Wonder,’ which you can see in the Home Landscape Garden now; ‘Waterlily,’ a well-named, ruffled variety; and ‘Album,’ the classic white colchicum. Like most bulbs, colchicum corms are planted in late fall so they can settle in before next year’s bloom.

In the meantime, we wonder: what surprises does your garden hold?