Unlike normal crocuses, autumn crocuses bloom at the end of the growing season. Their blossoms mark the end of summer, as the seasons shift from sunny and warm to cool and breezy. You’ll notice the naked, pink flowers emerging from the ground without any leaves.

Though they have the word crocus in their name, these perennials aren’t true crocuses. They resemble the spring-blooming bulbs. Autumn crocus refers to plants of the species Colchicum autumnale, while crocuses are in the genus Crocus.

A different species, the popular saffron crocus (Crocus sativus), also blooms in the fall around the same time as autumn crocus. This species is less hardy, and it produces an edible spice for use in cooking. Don’t confuse the two, as autumn crocuses are toxic while saffron ones produce edible stigmas.

What Is It?

Hidden corms produce cheerful pink flowers before frost.

The autumn crocus is a corm-forming perennial. A corm is an enlarged stem, whereas a bulb consists of swollen leaf tissues. From the corms, green leaves sprout in spring and pink blooms emerge from late summer through early fall. 

Native Area

Many regions now enjoy these cheerful seasonal flowers.

These crocuses originate from Europe, where they grow wild in many southern countries. They prefer cool winter temperatures and warm growing seasons with plenty of sunshine. Nowadays, they’re naturalized in many parts of the U.S. in states like Oregon, North Carolina, and Vermont. 

In garden culture, autumn crocus cultivars thrive in USDA hardiness zones 5 through 9. They may survive the winter in zone 4 if they have extra protection from harsh frosts. 

Characteristics

Naked stems surprise with pink-purple flowers every autumn.

These corm-forming perennials are unique. Most bulbs sprout leaves, then flowers, and they tend to do so in spring or summer. Autumn crocus grows leaves in spring, and they die in summer.

Then, in the fall, many pink-purple flower buds emerge from underground. They grow without leaves, hence the bulbs’ other famous name, “naked ladies.” They also go by the names fall crocus, meadow saffron, and wonder bulb. 

After the blooms fade, they die back, and the corm overwinters under the soil. New leaves emerge in spring, and the cycle repeats itself.

You can tell fall crocuses apart from saffron ones by their stamens, or male reproductive parts with pollen. True crocus flowers have three stamens, whereas plants in the genus Colchicum have six stamens in each of their blooms. 

Planting

These bulbs benefit from a summer planting. It’s too late to plant them once they’re blooming. If you notice they’re pretty this year and you want them for next season, make a note to plant them next summer.

Find corms for planting at garden centers, plant nurseries, and specialty online retailers. Or, try growing them from seeds! They take considerably longer to mature, but the challenge of growing them is well worth the rewards. 

Growing from Seed

Each seed may surprise with unique flower shades.

Grow these false crocuses from seeds for a variety of reasons. Perhaps you’d like to discover a new variety, or you’re looking for unique bloom colors. Seed-started plants are likely to differ from their parents, and you may stumble upon a new, exceptional cultivar while cultivating them.

Start by finding seeds. Collect them from well-performing plants in the landscape in late autumn, or purchase them from a retailer. Search for seeds of Colchicum autumnale to ensure you buy the right ones. 

Sow the seeds in pots with potting soil, and cover them lightly with a thin layer of the soil. Keep the dirt moist until the seedlings sprout, and give them bright light while they mature. They need a year or two outdoors before they’ll sprout, and the seedlings need to grow for four to five years before they’re ready to flower. 

Transplanting

Mid-summer planting guarantees blooms before the season ends.

For blooms in fall, you’ll need to plant autumn crocus corms by mid to late summer. It’s too late to plant once the blooms appear. You’ll have to wait until they fade before planting the corms. 

Plant the bulb-like corms in loamy, well-drained soil. Most garden soils work well, and you may amend them with compost to help them get better over time. Start by digging holes three to six inches deep, and space them half a foot apart. 

Place the corms right side up in the holes, then cover them with the soil you dug out earlier. Water the site, and keep it moist while the crocuses establish themselves. Place a fresh, two to three-inch-thick layer of compost on top of the dirt. It’ll feed and insulate the plants while they grow underground. 

How to Grow

These bulbs are easy to grow, and they’ll naturalize in gardens where they’re hardy. You’ll see exquisite clumps of cute flowers that pop up each autumn. The clumps will grow wider each year, and you can divide them to propagate the crocuses further. 

Light

Light exposure guides strong stems and colorful blooms.

These perennials need full sun to partial shade while they grow. They blend in well under larger trees and shrubs, though they do their best in full sun with six or more hours of direct sunlight.

Sunlight is especially important during the plants’ leafy phase, when they grow leaves in spring before the summer dormancy. They tolerate shade during the flowering phase, from late summer through fall.

Water

Summer dormancy allows soil to dry completely first.

Regular water is best during the two separate growing seasons. The corms need plenty of moisture while they sprout leaves and blooms. They’re drought-tolerant during the summer months when temperatures are warm. 

Avoid overwatering, especially during winter and summer. Let the soil dry on the surface before watering again. Container specimens need more water, as their pots dry more quickly than the ground. 

Soil

Clay or sandy soil benefits from compost addition.

Grow autumn crocus in well-drained soil. The corms dislike soggy situations, and they fare best in loamy, free-draining earth. 

If the site is clay-dense or too sandy, amend it with compost. The nutrient-rich soil amendment will decay over time and boost the dirt’s quality. Regardless of whether the site has too much clay or sand, compost is the solution for creating humus-rich loam. 

Fertilizing

Spring and autumn feedings support leaves and flowers.

These bulbs appreciate rich soils, and they’ll benefit from occasional fertilization during the growing season. Feed them once as they grow new leaves in spring, and again in autumn when the blooms appear.

Use an organic fertilizer to avoid harming soil microbes, and dilute it with water to help it soak into the ground. A well-balanced fertilizer with equal parts nitrogen, phosphorus, and potassium is best. 

Propagation

Propagate these perennials with division, or save their seeds to sow seedlings. Division is the typical route that gardeners use, as it’s easier and quicker working than starting plants from seeds. 

Division

Transplant lifted corms to create new garden clusters.

Divide healthy clumps every other year to multiply your planting stock. The corms form mini-corms under the soil that swell and enlarge into mature ones. Harvest these, take them elsewhere, and plant them again to spread them throughout the garden.

It’s best to divide from mid to late summer when the corms are dormant. If you know you want to divide this year, pay attention to the plants when they’re in their leafy form in spring. Place a flag in the center of each clump. Then, in summer, you’ll know exactly where to dig.

Dig a foot deep underground, a few inches outside of the clumps. Dig under them, then lift them out of the ground. They should lift easily while they’re dormant and relatively rootless. Place them in a cool, dark, and dry location until you’re ready to plant them. Or, plant them now! 

Seed Saving

Hybridizing flowers slowly produces exciting new garden options.

Though growing autumn crocus from seeds takes a long time, it’s a great way to discover new varieties or make new hybrids. Simply place the pollen from one variety’s flowers into those of another, and collect the resulting seeds in late winter or spring. 

The seeds form in pods near the ground. Pick the pods when they’re brown but before they open fully to ensure they don’t fall on the ground. Let the seeds dry, then place them in containers to store long-term. Keep the containers in a cool, dark place like a pantry or refrigerator. 

Popular Varieties

There are dozens of species and hybrids available for purchase. These are three of the most popular, though there are many options to choose from. Go for a classic autumn crocus here, or keep searching to find a funky new cultivar. 

Pleniflorum

Clumps spread gradually, adding color to any garden.

‘Pleniflorum’ fills the home garden with lush, purple blooms. The flowers are double flowers, meaning they have multiple rows of petals instead of a single one. 

Like the species, ‘Pleniflorum’ multiplies over time to make small clumps. Propagate them in summer and plant them in your meadows, lawns, and beds. 

Waterlily

Summer division helps propagate new, vibrant garden clumps.

‘Waterlily’ blooms resemble waterlilies because they’re lilac-purple and full of petals. Like ‘Pleniflorum,’ the flowers are double-petalled with many rows. They’re stunning alongside single-petal types!

This cultivar’s heavy blooms may need support to stay upright. Let them grow through a metal flower support, or prop them up with sticks and stones. 

‘Waterlily’ is a sterile hybrid, meaning it won’t grow seeds. Propagate it by dividing the corms in summer. 

The Giant

Height and color make these blooms garden showstoppers.

‘The Giant’ is so aptly named for its tall-reaching blooms. They may extend to a foot tall! The petals are purple on the outside and white on the inner portions.

As with ‘Waterlily’ blooms, ‘The Giant’ flowers may need support to stay standing. Help them with metal grates or strong supports. 

Common Problems

Relatively problem-free, these bulbs are favorites for their low-maintenance nature. They may occasionally have slugs, snails, or fungal infections. Watch for these pests when the weather is moist and cool in fall and spring. 

Pests

Early traps prevent slugs from damaging new shoots.

Slugs and snails are voracious eaters of foliage. They attack leaves, stems, buds, and anything green! They’ll even eat the flowers. Though they’re not common pests, they occasionally target autumn crocus populations. 

Monitor for slugs daily when they’re common. They thrive under the cool of fall and spring. Trap them with beer or dough traps, or place boards throughout the garden and uncover them in the morning. 

Diseases

Discard infected plants to prevent spreading fungal smut.

Fungal smut may infect the leaves, though it’s incredibly rare. It’s a fungal disease that targets fresh leaves. It forms a black coating with white patches. 

Smut stays in the soil for long periods of time. Instead of trying to save the original plants, discard them and plant a different species in the hole. Plant autumn crocus species elsewhere to starve the fungus of its hosts.