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Herbaceous Perennial

Penstemon hartwegii
  • RHS AGM
  • RHS Plants for pollinators

scarlet beard tongue

A bushy semi-evergreen perennial to 70cm in height, with narrow foliage and panicles or racemes of slender bright crimson flowers 4cm in length, marked white in the throat and borne on purple stems

Other common names
Hartweg penstemon

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Loam
Sand
Moisture
Well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Purple Red White Green
Autumn Purple Red White Green
Winter Green
Position
  • Full sun
Aspect

West–facing or South–facing or East–facing

Exposure
Sheltered
Hardiness
H4
Botanical details
Family
Plantaginaceae
Native to GB / Ireland
No
Foliage
Semi evergreen
Habit
Clump forming
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

Name status

Unresolved

How to grow

Cultivation

Grow in fertile, well-drained soil in full sun or partial shade. In cold areas, protect plant overwinter with a dry winter mulch. See penstemon cultivation for further advice

Propagation

Propagate by softwood cuttings in early summer or semi-hardwood cuttings in midsummer. Propagate by division in spring

Suggested planting locations and garden types
  • City and courtyard gardens
  • Cottage and informal garden
  • Gravel garden
  • Prairie planting
  • Wildlife gardens
  • Coastal
  • Patio and container plants
  • Flower borders and beds
Pruning

Deadhead after flowering to maintain vigour, then cut back to base in winter

Pests

May be susceptible to slugs, snails and chrysanthemum eelworms

Diseases

May be susceptible to a downy mildew

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