Colchicum speciosum Giganteum Group

RHS Plant Profile

giant meadow saffron Giganteum Group

Synonyms

Colchicum giganteum Arn.
Colchicum illyricum misapplied
Colchicum giganteum hort. ex Stef.
Colchicum illyricum superbum
Colchicum speciosum var. illyricum hort.

Bulbs Herbaceous Perennial

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An autumn-flowering bulb reaching 30cm tall, with clusters of large lilac flowers, without leaves. The leaves are green and broad and grow in spring, quite separate from the flowering season. Suitable for naturalising in grass

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or North–facing or South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Colchicaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Tufted
Potentially harmful: TOXIC if eaten. Wear gloves and other protective equipment when handling TOXIC to pets - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus: Colchicum are cormous perennials with usually coarse, broadly strap-shaped leaves which appear with or after the goblet-shaped flowers
Name Status: Accepted

How to Grow

Cultivation

Grow in good light in any moist but well-drained soil

Propagation

Propagate from seed or division

Suggested planting locations and garden types

Cottage and informal garden
Gravel garden
Wildflower meadow
Wildlife gardens
Flower borders and beds
Underplanting of roses and shrubs

Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free