Colchicum bornmuelleri is a beautiful autumn-flowering colchicum, producing elegant violet flowers at a time when much of the garden is beginning to fade. Commonly referred to as an Autumn Crocus or Naked Lady, its crocus-like flowers emerge directly from the ground without foliage, creating an eye-catching display during September and October.

Growing to around 15cm tall, Colchicum bornmuelleri is ideal for the front of borders, gravel gardens, beneath deciduous shrubs and amongst low-growing perennials. Once established, the corms can gradually increase to produce increasingly impressive clusters of autumn flowers.

• Botanical name: Colchicum bornmuelleri
• Common names: Autumn Crocus, Naked Ladies
• Plant type: Hardy, autumn-flowering cormous perennial
• Flower colour: Violet
• Flowering time: September-October
• Height: Approximately 15cm (6in)
• Spread: Approximately 10-20cm, gradually forming larger clumps
• Position: Full sun
• Soil: Fertile, well-drained soil
• Planting depth: 10-15cm
• Planting distance: Approximately 20cm apart
• Ideal for: Borders, gravel gardens, naturalistic planting and autumn colour

About Colchicum bornmuelleri

Colchicum bornmuelleri is grown for its attractive violet, goblet-shaped flowers, which appear in autumn. Despite its common name of Autumn Crocus, it is not a true crocus. Colchicums belong to the Colchicaceae family and have their own distinctive growth cycle.

The flowers emerge seemingly from bare ground in September and October, without accompanying leaves. This unusual characteristic has given colchicums the familiar name Naked Ladies. Their unexpected appearance can provide a valuable burst of colour between the main summer flowering season and the onset of winter.

Autumn Flowers Without Foliage

One of the most interesting features of Colchicum bornmuelleri is its seasonal growth pattern. The flowers appear independently in autumn, while the foliage develops separately, usually during spring.

The spring leaves are important because they replenish the underground corm and provide the energy required for the following autumn's flowers. Allow the foliage to remain in place until it has naturally yellowed and died back rather than cutting it down while still green.

Where to Plant Colchicum bornmuelleri

Choose a sunny position with well-drained soil. Colchicums can remain undisturbed for many years, so it is worth selecting a permanent position where their spring foliage can mature naturally.

The front of a mixed border is an excellent choice, as are gravel gardens and sunny areas beneath deciduous shrubs. They can also be planted amongst low-growing ground-cover plants, allowing the violet flowers to emerge through surrounding vegetation in autumn.

How to Plant Colchicum bornmuelleri Corms

Colchicum corms should be planted as soon as possible after arrival. Unlike many spring-flowering bulbs that can wait until later in autumn, colchicums naturally begin their flowering cycle relatively early and may attempt to flower even before they have been planted.

Plant the corms approximately 10-15cm deep and around 20cm apart, with the growing point facing upwards. Water after planting if the soil is particularly dry, but avoid positions that remain waterlogged during winter.

For the most effective display, plant several corms together in informal groups. Over time established plants can increase to create larger clumps.

Growing Colchicums in the UK

Colchicum bornmuelleri is well suited to UK gardens provided it has adequate drainage. Once planted, established corms require relatively little attention and can return reliably each autumn.

Heavy soils should be improved before planting by incorporating organic matter and suitable drainage material where necessary. Avoid planting in areas where water regularly collects during winter, as prolonged waterlogging can cause the corms to deteriorate.

Naturalising Colchicum bornmuelleri

Although each plant initially occupies relatively little space, established corms can gradually multiply to produce larger flowering clumps. Allowing them to remain undisturbed is generally the best way to achieve a more impressive display.

If established clumps eventually become overcrowded, they can be carefully lifted and divided while dormant. The separated corms can then be replanted to establish new groups elsewhere in the garden.

Planting Companions

The violet flowers look particularly attractive amongst low-growing green foliage and alongside other late-season plants. They can also be used with other colchicum varieties to create a mixture of pink, violet and white autumn flowers.

When choosing companion plants, remember that colchicums produce relatively substantial foliage in spring. Positioning them amongst perennials that develop later in the season can help disguise the leaves as they begin to fade.

Important: Colchicum Is Toxic

All parts of Colchicum are poisonous if eaten and contain colchicine. The plant should not be confused with edible crocus species or wild garlic. Wear gloves when handling if you have sensitive skin, and plant with appropriate care where children or pets have access to the garden.

Why Grow Colchicum bornmuelleri?

• Elegant violet autumn flowers
• Flowers during September and October
• Unusual flowers emerge without foliage
• Compact height of approximately 15cm
• Excellent for extending seasonal garden colour
• Suitable for sunny borders and gravel gardens
• Can gradually develop into larger clumps
• Low-maintenance once established
• Returns year after year in suitable conditions

Frequently Asked Questions

When does Colchicum bornmuelleri flower?
It flowers in autumn, typically during September and October.

How tall does Colchicum bornmuelleri grow?
The flowers reach approximately 15cm (6in) tall.

What is the spread of Colchicum bornmuelleri?
Allow approximately 10-20cm for an individual plant. Established corms can gradually multiply and form considerably wider clumps over time.

When should I plant Colchicum corms?
Plant them as soon as possible after receiving them. Colchicums have an early autumn flowering cycle and should not be stored unnecessarily before planting.

How deep should Colchicum bornmuelleri be planted?
Plant the corms approximately 10-15cm deep and around 20cm apart in well-drained soil.

Why does my Colchicum flower without leaves?
This is completely normal. Colchicums produce their flowers in autumn without foliage, which explains the common name Naked Ladies. Their leaves appear separately during spring.

Is Colchicum bornmuelleri the same as a crocus?
No. Although commonly called Autumn Crocus because of the similarity of its flowers, Colchicum belongs to a different plant family.

Is Colchicum poisonous?
Yes. All parts of the plant are toxic if ingested and should never be eaten.

With its distinctive growth cycle and rich violet flowers appearing in September and October, Colchicum bornmuelleri is an excellent choice for extending garden interest well beyond summer. Plant the corms promptly in a sunny, well-drained position and they can provide an increasingly attractive autumn display for years to come.