• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

× Heucherella 'Stoplight' (PBR)

heucherella 'Stoplight'

heucherella 'Stoplight'

© RHS

  • Other common names heucherella 'Stoplight'

  • Family Saxifragaceae

  • Genus x Heucherella are hybrids between Heuchera and Tiarella, and are evergreen, clump-forming perennials with ovate or rounded leaves and open panicles of small bell-shaped pink or white flowers over a long period

  • Details 'Stoplight' is a compact perennial forming a clump of maple-like, palmately-lobed yellow-green leaves, the main veins flushed with maroon, most intensely in spring. Summer leaves are more lime-green throughout. Small whitish flowers are borne on stems to 50cm tall in spring and early summer

Characteristics

  • Foliage Evergreen

  • Habit Clump-forming

  • 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

Colour

Sunlight

  • Full Sun

  • Partial Shade

  • Aspect South-facing or East-facing or West-facing or North-facing

  • Exposure Exposed or Sheltered

Soil

  • Sand

    Sand

  • Loam

    Loam

  • MoistureMoist but well-drained

  • SoilSand, Loam

  • pHNeutral

Size

  • Ultimate height 0.1-0.5 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in fertile, moist, but well-drained soil in sun or partial shade. If the soil is moist, a sunnier position may be tolerated. To prevent the rhizomes rising to the surface, mulch annually and divide every few years

Propagation Can be propagated by division; this genus need to be divided regularly. Lift the plant once in spring growth, taking small vigorous sections from around the edge. Each section should have good roots and 2-3 shoots

Suggested planting locations and garden types Flower borders and beds Ground Cover Underplanting of Roses and Shrubs Cut Flowers Banks and Slopes Garden Edging Cottage & Informal Garden Patio & Container Plants City & Courtyard Gardens

How to care

Pruning Remove dead leaves and deadhead

Pests vine weevils may be a nuisance

Diseases Rust diseases may be problematic

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