Colchicum giganteum, commonly known as Giant Meadow Saffron, is an impressive autumn-flowering colchicum prized for its exceptionally large rose-purple, goblet-shaped flowers. Also known as an Autumn Crocus or Naked Lady, its substantial blooms emerge directly from the ground without foliage, creating a dramatic display when many summer plants are beginning to fade.

Reaching approximately 25-30cm tall in flower, Colchicum giganteum is considerably taller and more imposing than many colchicums. It makes an excellent specimen for autumn borders, gravel gardens and naturalistic planting, particularly when several corms are grouped together to create a bold seasonal display.

• Botanical name: Colchicum giganteum
• Common names: Giant Meadow Saffron, Autumn Crocus, Naked Ladies
• Plant type: Hardy, autumn-flowering cormous perennial
• Flower colour: Rose-purple
• Flowering time: Autumn
• Height: 25-30cm (10-12in)
• Spread: Approximately 15-25cm, gradually forming larger clumps
• Position: Full sun
• Soil: Fertile, well-drained soil
• Planting depth: 10-15cm
• Planting distance: Approximately 20cm apart
• Ideal for: Autumn borders, gravel gardens, naturalistic planting and containers

About Colchicum giganteum

The name giganteum gives a good indication of what makes this colchicum special. Its large rose-purple flowers are carried considerably higher than those of many smaller colchicums, producing an eye-catching display close to the end of the traditional gardening season.

The flowers have the characteristic goblet-like form associated with colchicums, opening more widely in suitable weather to reveal their delicate internal details. Their rich colouring makes them particularly effective against green ground-cover plants or amongst the changing foliage of an autumn garden.

Why Are Colchicums Called Naked Ladies?

Colchicum giganteum has an unusual growth cycle. Its flowers emerge in autumn without any accompanying leaves, seemingly appearing from bare soil. This has resulted in the familiar common name Naked Ladies.

The foliage appears separately in spring. These leaves should be allowed to grow and die back naturally because they feed the underground corm and store the energy required to produce the following autumn's flowers.

Where to Plant Giant Meadow Saffron

Plant Colchicum giganteum in a sunny position with fertile, well-drained soil. A position towards the front or middle of a border works particularly well, where its unusually large autumn flowers can be appreciated.

It can also be grown in gravel gardens, amongst low-growing ground-cover plants or beneath deciduous shrubs where sufficient sunlight reaches the soil. Avoid permanently wet or waterlogged positions, particularly during the dormant period.

How to Plant Colchicum giganteum Corms

Colchicum corms should be planted immediately upon arrival. Their flowering cycle begins relatively early and corms kept out of the ground for too long may begin producing flowers before they have been planted.

Plant the corms approximately 10-15cm deep and 20cm apart, positioning each corm with its growing point upwards. For a particularly impressive display, plant several corms in an informal group rather than individually around the garden.

Once established, the corms are best left undisturbed and can gradually increase to form larger clumps.

Growing Colchicum giganteum in the UK

Giant Meadow Saffron is a hardy perennial suitable for UK gardens. The most important requirement is good drainage, as the corms should not remain in persistently waterlogged soil.

On heavier ground, improve drainage before planting by incorporating organic matter and grit where appropriate. Once established in a suitable site, colchicums require relatively little maintenance and can return reliably year after year.

Spring Foliage

Although Colchicum giganteum is primarily grown for its autumn flowers, gardeners should also allow space for the foliage that appears during spring. The leaves can be substantially larger than the autumn flowers might suggest.

Do not tie, cut or remove healthy green leaves. Allow them to yellow and die back naturally. Planting colchicums amongst later-emerging perennials can help disguise the foliage as it begins to fade.

Naturalising and Established Clumps

Colchicums are particularly attractive when allowed to establish over several years. Individual corms can gradually multiply, creating increasingly substantial groups of rose-purple flowers each autumn.

If a mature clump eventually becomes overcrowded, the corms can be lifted and divided while dormant and replanted immediately. Otherwise, they are generally best left undisturbed.

Colchicum giganteum in Containers

The spectacular flowers can also be enjoyed in containers, provided the pot is sufficiently deep and has excellent drainage. A group planted together can create an impressive autumn display on a patio or near an entrance where the flowers can be viewed at close range.

Use a free-draining compost and avoid allowing containers to remain saturated for prolonged periods. As the plants also produce spring foliage, choose a container large enough to accommodate their complete seasonal growth cycle.

Important: Colchicum Is Poisonous

All parts of Colchicum giganteum are poisonous if eaten and contain colchicine. Despite the common name Meadow Saffron, it must never be confused with true saffron, Crocus sativus, or treated as an edible plant. Take particular care when planting where children or pets may have access.

Why Grow Colchicum giganteum?

• Exceptionally large rose-purple flowers
• Impressive 25-30cm flowering height
• Provides valuable colour during autumn
• Distinctive flowers appear without foliage
• Excellent planted in groups
• Suitable for borders and gravel gardens
• Hardy and perennial in UK gardens
• Can gradually develop into larger clumps
• Low-maintenance once established

Frequently Asked Questions

How tall does Colchicum giganteum grow?
The flowers typically reach around 25-30cm (10-12in) tall, making this an impressively large colchicum.

What is the spread of Colchicum giganteum?
Allow approximately 15-25cm for each plant. Established corms can multiply over time and eventually form much broader flowering clumps.

When does Colchicum giganteum flower?
It is an autumn-flowering species, producing its large rose-purple flowers after the summer growing season.

When should I plant Colchicum giganteum corms?
Plant the corms as soon as possible after receiving them. Colchicums can begin their autumn flowering cycle even while out of the ground, so they should not be stored unnecessarily.

How deep should I plant the corms?
Plant approximately 10-15cm deep and around 20cm apart in a sunny, well-drained position.

Why are colchicums called Naked Ladies?
Their autumn flowers emerge without leaves, giving the appearance of flowers rising directly from bare ground. The foliage appears separately in spring.

Is Giant Meadow Saffron actually saffron?
No. Despite its common name, Colchicum giganteum is not the edible saffron crocus. It is a different plant and is poisonous if consumed.

Should I remove the spring leaves?
No. Allow the foliage to yellow and die back naturally. The leaves replenish the corm and are essential for producing strong flowers the following autumn.

With its large rose-purple blooms and impressive 25-30cm height, Colchicum giganteum is one of the more dramatic choices for autumn colour. Plant the corms promptly in a sunny, well-drained position and allow them to establish into increasingly impressive clumps for a spectacular display year after year.