• 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

Penstemon 'Pensham Charlotte Louise' (Pensham Series)

penstemon 'Pensham Charlotte Louise'

penstemon 'Pensham Charlotte Louise'

© RHS

  • Other common names penstemon 'Pensham Charlotte Louise'

  • Family Plantaginaceae

  • Genus Penstemon may be deciduous or evergreen perennials or subshrubs, with simple, narrow leaves and racemes or panicles of bell-shaped or funnel-shaped flowers in summer and early autumn

  • Details

    'Pensham Charlotte Louise' is a herbaceous perennial 75cm high with semi-evergreen leaves and many flowers which are deep pink-red, the throats striped with pale pink and white and edged in darker pink, from midsummer to early autumn

Characteristics

  • Foliage Semi-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)

    H4

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureWell-drained

  • SoilLoam, Chalk, Sand

  • pHNeutral, Acid, Alkaline

Size

  • Ultimate height 0.5-1 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 full sun or light shade in a position sheltered from frosts and drying winds; in autumn, cut plants down by two-thirds of their height and protect with a dry mulch; for more advice, see penstemon cultivation

Propagation Propagate by softwood cuttings in early summer or semi-ripe cuttings in midsummer, by division in spring, or by layering

Suggested planting locations and garden types Flower borders and beds Cottage & Informal Garden City & Courtyard Gardens

How to care

Pruning Deadhead to encourage a longer flowering season; in autumn, cut plants down to about a third of their height to prevent windrock but leave some protection from frosts; in late spring or early summer after new growth appears and after frosts are over, cut out old stems

Pests May be affected by slugs and snails, and by chrysanthemum eelworm

Diseases Generally disease-free but may be affected by powdery mildews and grey moulds

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