Helleborus × hybridus 'Black Swan'

RHS Plant Profile

hellebore 'Black Swan'

RHS

Herbaceous Perennial

A clump-forming perennial to about 60cm with leathery, deeply lobed, dark green leaves that usually persist through winter. From late winter to mid-spring, sturdy upright stems bear outward-facing, double, purple-black flowers with white stamens

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam

Max Height

0.5-1 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 0.5-1 metres

Growing Conditions

Chalk Clay Loam

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

Position

Full sun Partial shade

Aspect: North–facing or South–facing or East–facing or West–facing
Exposure: 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: Ranunculaceae
Native to GB/Ireland: No
Foliage: Semi evergreen
Habit: Clump forming
Potentially harmful: Harmful if eatenskin irritant. Wear gloves and other protective equipment when handling. Pets: Harmful if eatenskin irritant. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus: Helleborus can be rhizomatous, herbaceous or semi-evergreen perennials forming a clump of pedate basal leaves, or evergreen with erect, leafy stems. Large, bowl-shaped flowers are borne in loose clusters in late winter or spring
Name Status: Accepted

How to Grow

Cultivation

Will tolerate a wide range of conditions, but does best in fertile, moisture-retentive, humus-rich but well-drained soil which is preferably heavy, and neutral or alkaline, in a position with shelter from strong, cold winds and in dappled shade, mulched every autumn with leaf mould, chipped bark or other organic matter; for more advice, see hellebore cultivation

Propagation

Propagate by division of large clumps in early spring, watering well until they are established

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Flower borders and beds
Underplanting of roses and shrubs

Pruning

Remove old leaves to help prevent hellebore leaf spot, and deadhead by removing old faded flower stems

Pests

May be susceptible to hellebore aphid, hellebore leaf miner and snails

Diseases

May be susceptible to hellebore leaf spot and hellebore black death