Sempervivum calcareum 'Grigg's Surprise'

RHS Plant Profile

houseleek 'Grigg's Surprise'

Synonyms

Sempervivum calcareum 'Monstrosum', Sempervivum tectorum subsp. monstrosum

Alpine Rockery Cactus Succulent Herbaceous Perennial

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A large, slow-growing, mat-forming evergreen perennial alpine forming rosettes of long, quill-shaped blue-green leaves with dark, burgundy-red tips. Rarely produces flowers, but if it does these appear on mature plants in summer, and are star-shaped and pink

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: 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): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Crassulaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Matforming
Genus: Sempervivum are evergreen perennials forming mats of fleshy-leaved rosettes, often attractively coloured, with star-shaped pink or pale yellow flowers in summer
Name Status: Accepted

How to Grow

Cultivation

Grow in moderately fertile well-drained soil in full sun. Protect from excessive winter wet. Suitable for rock garden, scree bed, wall crevice, trough or alpine house. See hardy cacti and succulent cultivation for further advice

Propagation

Propagate by offsets in spring

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Gravel garden
Patio and container plants
Rock garden

Pruning

No pruning required

Pests

May be susceptible to sempervivum leaf miner, slugs, snails, and vine weevil

Diseases

May be susceptible to a rust