Heuchera 'Isla' (Heucheraholics Series)

RHS Plant Profile

alum root 'Isla'

RHS / Joanna Kossak

Herbaceous Perennial

A compact, clump-forming variety with silvery-purple leaves with darker veining. Tall, upright stems of pinky white flowers are produced from spring until early summer and are very attractive to bees

Position

Full shade, Partial shade

Soil Types

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

Clay Loam Sand

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

Position

Full shade Partial shade

Aspect: East–facing or North–facing or South–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): H6
Drought Resistance: Yes

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Saxifragaceae
Native to GB/Ireland: No
Foliage: Semi evergreen
Habit: Clump forming
Genus: Heuchera are more or less evergreen, clump-forming perennials with attractive, rounded, shallowly palmately lobed leaves and racemes or panicles of small, tubular flowers, often with colourful calyces
Name Status: Accepted

How to Grow

Cultivation

Grow in fertile, humus-rich, moist but well-drained soil, in partial or full shade, and mulch every year; the rootstock tends to push upwards, so every few years, in late summer or early autumn, divide and re-plant with only the crown above ground

Propagation

Propagate by division in late summer or early autumn

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Patio and container plants
Flower borders and beds
Underplanting of roses and shrubs
Banks and slopes
Ground cover

Pruning

No pruning required. Remove dead leaves

Pests

May be susceptible to vine weevils and leaf and bud eelworm

Diseases

May be susceptible to heuchera rust