Plant Palette

Plant Palette

Fall Crocus

Photo of Jennifer Schultz Nelson

Jennifer Schultz Nelson
Extension Educator, Horticulture

Mention planting bulbs this time of year and most people have visions of springtime daffodils and tulips. But there are some bulbs that if planted in late summer, will bloom this fall. I don't know about you, but my garden could certainly use some bright new blooms after a long hot summer that has left my garden looking absolutely exhausted.

If you garden in any capacity, you're probably starting to see lots of new catalogs in your mail recently. Most are advertising fall as "bulb planting time" with glossy photos of colorful spring bulbs. Look carefully and you may spot a page or two of fall blooming bulbs. They don't get nearly the press that the spring bulbs do, but if you would like to have some unique new blooms to perk up your garden this fall, they're worth a second look.

I am always looking for something that will reinvigorate the garden late in the season. There seems to be no limit of plants that bloom nonstop through the late spring and summer, but having a few new flowers pop up in the fall adds some variety and changes to your garden scene. It's nice to have some anticipation in the garden, something to look forward to over the course of the growing season.

What I thought was one species of fall bulb is actually two, due to the 'wonderful' world of common names. A lot of people may think you're a garden snob if you routinely use the Latin names for plants, but in the long run searching for a plant by its Latin name makes it more likely that you will get what you wanted in the first place.

My confusion started with an ad for 'fall crocus' in a catalog. I already have the fall blooming crocus Crocus sativus, the crocus that produces the ultra-expensive spice saffron. I assumed that the 'fall crocus' this company was advertising were of the genus Crocus. Boy was I wrong.

It turns out there is a plant called fall crocus that is only distantly related to the genus Crocus. Plants in the genus Colchicum are commonly referred to as fall crocus in catalogs and other publications, but they are their own separate genus and family. Their flowers look similar to Crocus, which is probably where the common name fall crocus originated. If you trace back in their ancestry, true Crocus and Colchicum are both related to lilies, but that's where the similarity ends.

The genus Colchicum includes about sixty species of flowering plants that grow from corms, which are botanically modified stems. Colchicums are native to West Asia and the Mediterranean. The Colchicum's name comes from an alkaloid chemical called colchicine contained in its leaves, seeds and corms. Colchicine is a powerful poison, but in lesser doses it has had medicinal uses in treating inflammation caused by gout and in plant breeding, where it is used to double chromosome numbers as part of new plant cultivar development. Colchicine also makes Colchicums unpalatable to critters like deer and squirrels, which is helpful to many gardeners!

Colchicums tend to bear their crocus-like flowers in clusters, rather than singly like true Crocus. They are also anywhere from six to ten inches in height, a lot taller than Crocus, that is usually only three to six inches tall.

Most flowers are described as vase or goblet-shaped, but the cultivar 'Waterlily' has double flowers that do in fact look like a pink waterlily. Typical Colchicum colors are white or shades of pink or purple, with yellow occasionally seen. True fall blooming Crocus are commonly seen in the same colors, including yellow, but also have some bicolor or striped cultivars.

Colchicums are typically planted in August and September. In contrast, true fall blooming Crocus should be planted slightly earlier, in July and August. Both Colchicums and true fall blooming Crocus should flower the first year they are planted, assuming they are planted at the proper time. Mail-order companies typically ship these corms in late summer, and advise consumers to plant the corms immediately upon receipt.

When true fall blooming Crocus blooms, usually their grass-like foliage is present at the same time. The Colchicum's foliage appears in spring and lingers for a few weeks, fading away by early summer. Then just when you've forgotten you ever planted them, their flowers appear like magic in the garden, without foliage.

Both Colchicum and Crocus prefer to be planted in well-drained soil, in full to partial sun. Give these underused plants a little space in your garden this year, and you may be hooked!

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