Colchicum speciosum

Colchicum speciosum: how do you recognise it?

Habit

Corm with flowers 20–25 cm tall; in spring a clump of leaves 25–30 cm tall.

Leaf

Large, broadly lance-shaped, glossy green, in spring; dies back in June.

Flower

Large goblets 10–20 cm tall, pinkish lilac with a white throat or entirely white; a long pale tube instead of a stem.

Flowering

September and October.

Corm

Large corm with a brown, papery skin.

Flowering: September–October · Plants: July–August

Why grow it?

• Large, eye-catching flowers in autumn, when most bulbs have long been dormant.
• A late source of pollen for bees and bumblebees.
• Easy and robust: returns every year and forms large clumps after a few years.
• Lovely in grass, under shrubs or at the front of a border with late perennials.
• White forms such as ‘Album’ light up the autumn garden.

Colchicum speciosum: where does it grow best?

• Sun to light shade.
• Well-drained soil: sand, loam or light clay, chalky is fine.
• Normally moist; no wet feet.
• Not at the very front: the large leaves are conspicuous in spring and die back untidily in June.
• Plant 5–10 corms per m² in small groups.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Normal

Size

0.25 m tall, 0.2 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Michaelmas daisy: Flowers at the same time in blue and purple.
• Stonecrop: Pink flower heads in autumn and sturdy leaves to support the goblets.
• Hardy geranium: Low leaves that support the bare flowers and hide the dying foliage in June.
• Autumn cyclamen: Small pink flowers under shrubs in the same months.
• Ornamental grass: Autumn colour and movement behind the flowers.

Colchicum speciosum: when and how to plant it?

Plant in July–August.

1. Plant the corms in July–August, as soon as they are on sale: they want to go into the ground quickly.
2. Set them 10–15 cm deep, tip upwards, 15–20 cm apart.
3. Wear gloves when planting: the corms are poisonous.
4. Plant in groups under shrubs, in grass or among perennials that hide the dying leaves.
5. Water after planting if the soil is dry.

Care

Water

Usually not needed.

Feeding

Some compost in spring, when the leaves appear.

Leaves

Let the leaves die back completely in spring: the corm draws its strength from them.

Mowing

In grass: mow only after the leaves have died back in June, and stop from late August.

Dividing

Crowded clumps flower less; divide them in summer.

Tip: Plant them in a low ground cover such as hardy geranium or lady’s mantle: it supports the flowers in autumn and hides the yellowing leaves in June.

Colchicum speciosum: when to prune it?

When: No pruning is needed.

How:

• Remove faded flowers when they look untidy.
• Remove the leaves only when they are completely yellow, usually in June.

Caution: Wear gloves when removing leaves or flowers: all parts are poisonous.

Pruning calendar and basic rules

Propagation

Division

Lift crowded clumps in July once the leaves have died back, separate the corms and replant at once.

Sowing

Possible, but it takes 4–5 years to the first flowers.

Colchicum speciosum: how does it get through the winter?

Hardy to −25 °C.

• Very hardy, to about −25 °C.
• No protection needed.
• In winter there is nothing to see above ground; the leaves appear in March.
• In wet, heavy soil the corms may rot.

Diseases and pests

• Flopping flowers: Rain and wind knock over the large goblets. Plant them among low plants or in grass that supports them.
• Slugs: Sometimes eat the flowers and young leaves.
• Few flowers: Crowded clumps or leaves removed too early. Divide the clumps and let the leaves die back.

Through the year

• March: Leaves appear.
• April: Add compost.
• June: Leaves die back; only remove them then.
• July: Plant corms. Divide crowded clumps.
• August: Plant corms. Stop mowing in grass.
• September: Flowering.
• October: Flowering ends.

Edible and useful

Not edible. All parts of autumn crocus are highly poisonous (colchicine), to pets and livestock too; there is no antidote. The leaves appear in spring and are sometimes mistaken for wild garlic, the purple autumn flowers for saffron crocus. Wear gloves when planting the corms and keep children and pets away. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Colchicine from colchicums is used in medicine against gout, but only in very small, precise doses.
• The name Colchicum refers to Colchis, an ancient region on the Black Sea in present-day Georgia, known from the Greek myth of the Golden Fleece.