Penstemon 'Southgate Gem'

RHS Plant Profile
penstemon 'Southgate Gem'

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penstemon 'Southgate Gem' RHS
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Herbaceous Perennial

'Southgate Gem' is a herbaceous perennial 70-75cm high with semi-evergreen leaves and deep pink-red flowers with burgundy and white throats from midsummer to midautumn

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
2–5 years
Max Spread
0.1-0.5 metres
Max Height
0.5-1 metres

Growing Conditions

Chalk Loam Sand
Moisture
Moist but well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
West–facing or South–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)
H4

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

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
Accepted

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-ripe cuttings in midsummer, by division in spring, or by layering

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Coastal
  • Gravel garden
  • Wildlife gardens
  • Flower borders and beds
  • Wall side borders

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 susceptible to slugs and snails and chrysanthemum eelworm

Diseases

May be susceptible to powdery mildews and grey moulds but generally disease-free