Lupinus 'Blacksmith'

RHS Plant Profile

lupin 'Blacksmith'

Herbaceous Perennial

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A vigorous, upright, clump-forming herbaceous perennial with palm-shaped mid-green leaves. Dense spikes of purple and white flowers appear late spring, flowering throughout the summer

Position

Full sun, Partial shade

Soil Types

Loam, Sand

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

Loam Sand

Moisture: Well–drained
pH: Acid or Neutral

Position

Full sun Partial shade

Aspect: 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): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Fabaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming, Columnar upright
Potentially harmful: Harmful if eaten. Wear gloves and other protective equipment when handling. TOXIC to pets if eaten (dogs, cats, rabbits, tortoises) - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus: Lupinus can be annuals, perennials or shrubs, with palmate leaves and showy terminal racemes of pea-like flowers
Name Status: Accepted

How to Grow

Cultivation

Grow in moderately fertile, humus-rich, light, moist but well-drained soil in full sun or light, dappled shade. May require support (see staking perennials). See lupin cultivation This plant was included in the RHS Lupinus (lupin) trial 2024-2025 https://www.rhs.org.uk/plants/trials-awards/plant-trial-results/lupinus

Propagation

Propagate by basal stem cuttings

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Coastal
Patio and container plants
Cut flowers
Flower borders and beds

Pruning

Deadhead to encourage a second flush of flowers

Pests

May be susceptible to slugs and lupin aphid

Diseases

May be susceptible to powdery mildews, rots, a leaf spot and a virus