Sempervivum arachnoideum 'Rubrum'

RHS Plant Profile

cobweb houseleek 'Rubrum'

RHS

Synonyms

Sempervivum 'Rubrum'

Alpine Rockery Cactus Succulent

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An evergreen perennial forming a mat of fleshy rosettes 1-3cm across, leaves mostly dark red, with cobwebby white hairs at the tips. Starry pink flowers 1cm in width in flatclusters on upright stems to 12cm

Position

Full sun

Soil Types

Loam, Sand

Max Height

Up to 10 cm

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 5–10 years
Max Spread: 0.1-0.5 metres
Max Height: Up to 10 cm

Growing Conditions

Loam Sand

Moisture: Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or North–facing or West–facing or East–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: 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: Unresolved

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

Propagation

Propagate by rooting offsets in spring

Suggested planting locations and garden types

Cottage and informal garden
Gravel garden
Patio and container plants
Rock garden
Flower borders and beds
Garden edging
Ground cover

Pruning

No pruning required

Pests

May be susceptible to vine weevil and sempervivum leaf miner

Diseases

May be susceptible to a rust