Autumn crocus, Colchicum autumnale, is not actually a crocus at all.
While it may resemble that familiar spring-blooming member of the iris family, Colchicum is a separate genus in the Colchicaceae family that grows from a bulb-like corm.
Its cup-like blossoms are pink or purple, often with a white center. They may also be all white.
Many have a single row of petals that open very wide, more like a lily than a crocus. Some cultivated varieties have multiple rows of petals and resemble water lilies.
In this article, you’ll learn all you need to know to grow C. autumnale, a unique flower that offers lush foliage in the spring and crocus-like blossoms in the fall.
Also known as meadow saffron, C. autumnale is toxic if ingested, and must not be confused with the saffron crocus, Crocus sativus, from which the gourmet spice saffron is derived.
Cultivation and History
C. autumnale is different from spring-blooming crocuses and other autumn crocus-type plants, such as Sternbergia lutea, a yellow flower in the iris family.
Photo via Alamy.
Flowers with no stems or leaves rise from corms in the fall. This growth habit has earned these flowers the nickname “naked ladies.”
But don’t confuse this one with another flower that goes by the same nickname, Amaryllis belladonna, a pink late-summer lily that blooms after its foliage withers.
Don’t you just love botany?!
After the naked ladies of C. autumnale bloom and fade, the corms have a resting period of winter dormancy.
Photo via Alamy.
In the spring, tulip-like foliage appears. This is followed by the emergence of a fertilized ovum, or fruit, that looks like a green nut.
As summer gets underway, the foliage turns yellow, then decays to brown.
C. autumnale ovum, or fruit. Photo by BerndH, Wikimedia Commons, via CC BY-SA.
Each year, the parent corm produces an offset, or daughter, that takes the place of the original corm for reproductive growth, continuing the plant’s unusual life cycle.
The most fascinating part is that via an organ referred to as a protuberance, and together with contractile roots, the daughter bulb is able to pull itself deeper into the soil, where it settles into its mature position and produces additional offsets for vegetative growth.
In addition to exceptional traits such as a self-settling corm, bare-stemmed flowers, leafing out in spring, and blooming in fall, colchicum has six stamens, twice as many as spring crocus flowers.
This flower has an intriguing history, as well.
A monograph by M. R. Lee of the Royal College of Physicians Edinburgh titled “Colchicum autumnale and the gout. Naked ladies and portly gentlemen” describes this corm flower’s storied past.
It is native to the UK and most of southern and central Europe, and has naturalized in Sweden, Denmark, and New Zealand.
Colchicum takes its name from Colchis, situated in today’s western Georgia, in Eastern Europe. Some of the earliest information about it is quite sad, beginning with Greek slaves in dire conditions ingesting it in order to end their unbearable lives.
Byzantine physicians learned that the corms contain colchicine, an anti-inflammatory that proved valuable for treating gout. However, preparation was an arduous process and the dosage had to be precise, or the result was toxic.
By the 1600s, colchicum was well known by Moorish people as a “purgative” for gout. However, by the 1700s, such treatments were banned as folk remedies that did more harm than good.
In the early 1800s, George Augustus Frederick, then Prince Regent and future King of England (George IV), suffered greatly from gout and declared that he would take colchicum regardless of the bans and warnings.
He lived to tell the tale, and by the late 1800s, methods for its preparation and dosages were far more reliable. Sadly, dogs were used in the experimentation that brought them to this point.
By the 1940s, scientists learned that colchicum also has antimitotic properties, meaning it could slow down the division of cells and possibly aid in treating malignancies.
As of 2011, bans were imposed on non-FDA-approved oral administration of colchicine. At the time, there was only one approved producer, and the product was called “Colcrys.”
As of 2015, scientists were in the midst of a 12-year study of its potential use in the treatment of cancer in gout patients.
Today, Colcrys is available for the treatment of gout (as well as familial Mediterranean fever), and research is ongoing.
An illuminating account, to say the least!
Again, I caution you not to consume any part of this flower or its corms, as we move on to discuss growing it in the home garden.
There are two ways to introduce this flower to your landscape: via seeds or corms.
You may grow C. autumnale from seed. However, the biggest complaint from gardeners is that they never sprout. This is because it takes at least two years for seeds to germinate.
They have to experience periods of warming and cooling, moisture and darkness, and often appear years after they were planted.
In addition, some cultivated varieties produce sterile seed.
Corms provide a faster and more reliable way to get started. They are available in late summer for immediate planting.
How to Grow
Around the middle of August, nurseries and online purveyors stock C. autumnale.
Once you have it in hand, plant it, because the corms will bloom even before you are able to get them into the ground, and the flowers are fragile.
To begin, choose a location with full sun to part shade.
The soil should be organically rich and well-draining. The ideal pH is slightly acidic to neutral, between 6.0 and 7.0.
To determine the quality and acidity of your soil, conduct a soil test through your local cooperative extension service office. To improve drainage and increase acidity, add compost or leaf mulch.
Work the soil to a depth of six inches, until it is crumbly. Mix in organic matter as needed.
Some folks like to add a little bone meal to the soil at this point, for a phosphorus-rich boost to jump-start root growth. A sprinkling will do.
Place each corm pointy side up, three inches deep.
Leave six inches between corms. This spacing allows for adequate airflow during the foliage phase each spring.
Note: Some folks like to cluster the corms in groups. Just remember, each corm produces multiple blooms, and while the flowers are slender, the leaves need room to spread at least six or up to nine inches outward.
Cover the corms with soil, tamp it down, and water well.
In the spring, provide an inch of water per week. This includes rain, so be sure to use a rain gauge.
Stop watering once the leaves turn yellow.
When flowers appear in the fall, water sparingly in the absence of rain.
The keys to successful corm planting are to:
- Add bone meal to stimulate root growth.
- Place corms pointy side up.
- Plant at a depth of three inches.
Minimal care is required for this plant. If you’ve grown crocuses in the past, you’re ready to grow C. autumnale.
Here’s what you need to do:
Supply one inch of water per week in the spring, and very little in the fall.
Keep the garden weeded to minimize competition for water, and provide fewer places for mold spores to germinate.
Apply a slow-release, all-purpose granular bulb food per package instructions as leaves emerge in the spring.
After the foliage turns brown, you may divide and transplant corms as desired.
And finally, if you find the stemless, leafless flowers to be too floppy, provide support for future blooms in the form of companion plants, which we’ll discuss shortly.
Cultivars to Select
In addition to the true botanical species, there are cultivated varieties of C. autumnale as well. Here are a few you might like:
C. autumnale ‘Alboplenum’ is a “double” blossom with multiple white petals. Heights range from eight to 12 inches, and each corm can produce up to eight flowers.
C. autumnale ‘Giant’ has deep lilac-pink petals with white centers. Mature heights range from 10 to 12 inches, with up to 10 flowers per corm.
C. autumnale ‘Waterlily’ is a double bloom with multiple lavender-pink petals.
C. autumnale ‘Waterlily’
This is a sterile cultivar that does not produce viable seeds. Heights reach six inches. Each corm produces three to five blossoms.
Find corms now from Home Depot in packages of three.
Managing Pests and Disease
C. autumnale is not prone to insects or infection. However, poor drainage and/or overwatering may cause moisture buildup that invites snails and slugs.
Remove them by hand, or set the appropriate traps to catch them.
In addition, soggy conditions may make corms vulnerable to fungal disease and rotting. Once underway, damage is likely irreparable. Be proactive with well-draining soil and avoid overwatering.
In 2013, it was reported that dark, sooty spore masses of Urocystis colchici fungi were observed on the foliage of C. autumnale, the UK’s only native autumn crocus. A type of “smut fungus,” it’s so rare that it’s endangered, and picking the flowers and disturbing the fungus is prohibited.
Autumn crocus is well-suited to placements where it can naturalize, spreading its cheerful clusters of blooms for an ever-expanding display.
It is very attractive in the dappled sunlight beneath loose-branched trees, and is equally at home in low-profile rockeries, drifts, and meadows.
Beware of planting the corms in a lawn. The flowers may be dainty, but the leaves are bulky.
Photo via Alamy.
Good companion plants for C. autumnale include ground covers and seasonal perennials that share the same cultural requirements, those that can share space well with the leaves in spring, and the flowers in fall.
They’re great for hiding withering leaves and supporting fragile flowers.
As for wildlife, the plants do not attract deer, and they provide a source of pollen for late-season foraging bees.
Quick Reference Growing Guide
|Plant Type:||Flowering corm||Flower / Foliage Color:||Pink, purple, white/green|
|Native To:||Europe, Ireland, UK||Maintenance:||Low|
|Hardiness (USDA Zone):||4-8||Soil Type:||Organically-rich|
|Bloom Time / Season:||Late summer, early fall||Soil pH:||6.0-7.0|
|Exposure:||Full sun, part shade||Soil Drainage:||Well-draining|
|Spacing:||6 inches||Attracts:||Late season bees|
|Planting Depth:||3 inches||Companion Planting:||Ground covers, seasonal perennials|
|Height:||6-12 inches||Uses:||Containers; naturalize in dappled woodlands, drifts, meadows, rockeries|
|Pests & Diseases:||Slugs, snails; fungal smut|
What Was She Thinking?
Like tipsy party guests, you really do have to wonder about flowers that can’t hold themselves up because their leaves are dancing to a different drummer.
C. autumnale may be a bit quirky, but I love that in a plant. Don’t you?
Add it to your garden planner, and remember to buy your corms as soon as they are available in the summer.
Stay away from seeds, unless you’re prepared to wait two years or more for them to germinate.
Plant your corms immediately, in a location with organically rich, slightly acidic, well-draining soil, and you should enjoy flowers by late summer or early fall.
And in this age of bizarre weather, killer bees, locusts, and spotted lanternflies, don’t be surprised if the masked neighbors strolling past your home stop to marvel at Mother Nature’s glorious gift: crocuses blooming in the fall.
Have you grown autumn crocus? Let us know in the comments below, and feel free to share a photo!
And for more information about flowering bulbs for your garden, check out these guides next:
© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Product photo via Home Depot. Uncredited photos: Shutterstock.
About Nan Schiller
Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!