Penstemon
An attractive group of short lived, slightly tender, flowering perennials and subshrubs, which add a splash of summer colour to borders and rock gardens. Easily grown from seed. The more tender herbaceous forms are usually treated as half-hardy annuals or biennials.
Family: Plantaginaceae (plantain family)
Botanical Name: Penstemon
Common Names: Beardtongue, golden-beard, beardlip.
Foliage: Deciduous or evergreen, simple, narrow mid-green leaves, sometimes glossy.
Flowers: Tubular/funnel shaped flowers in a wide variety of colours.
Flowering Period: Summer to early autumn.
Soil: Well-drained, fertile soil (chalk, sand or loam). Any pH.
Conditions: Best in full sun but will tollerate light shade. Plant in an east, west or south facing aspect.
Habit: Bushy.
Type: Herbaceous perennial or sub-shrub.
Origin: North and Central America.
Hardiness: Hardy in southern and coastal regions of the UK.
Planting and Growing Penstemon
Plant in spring. Alpines can be planted from autumn to spring.
Best planted in a moderately fertile, free draining soil, in full sun. Avoid waterlogged conditions.
Can also be grown as summer flowering bedding in cooler regions.
Ideal for the middle of a summer flower bed or border. Dwarf forms are ideal for the rock garden.
The flowers provide nectar and pollen for bees and other pollinating insects.
Taking Care of Penstemon
Water well in dry weather.
Penstemons are reliable in sheltered, warmer areas but can be killed by severe winter frosts. Protect from winter wet and provide some winter protection in cold areas.
Pruning Penstemon
Deadhead regularly to encourage further flowering.
Leave old foliage on the plants for additional winter protection and cut back in the spring. Alternatively, cut down stems in autumn and protect the crowns with a mulch over winter.
Pests and Diseases
Susceptible to attack by slugs, snails and eelworms. Can be affected by powdery mildews.
Propagating Penstemon
Raise from seed sown in trays in under glass in gentle heat in February. Species can be sown in the open in summer.
For named cultivars and hybrids, strike cuttings of non-flowering shoots in July-August and root in a free draining compost in a propagator.
Popular Varieties of Penstemon
There are many different cultivars of Penstemon available from medium to dwarf height. Flower colours range from shades of purple and red to pink and blue, often with a white throat.
Penstemon Arabesque bears large bell-shaped blooms over a long flowering period. Available at You Garden.
Penstemon Apple Blossom a very attractive variety with subtle pale pink/white flowers. Height to 32in (80cm). Available from Gardening Express.
Penstemon Alice Hindley a large-leaved perennial that bears attractive large tubular-bell-shaped, pale lilac-blue flowers from midsummer to autumn. Available from Gardening Express.
Penstemon barbatus (half-hardy) a bushy plant with glossy, lance-shaped leaves and slender, tall stems topped with narrow tubular flowers in summer. Height to 36in (90cm), spread 18in (45cm). Good cultivars include 'Twizzle' with narrow red flowers - available from Thompson & Morgan. The variety praecox produces upright spikes of tubular flowers that range from pink through to purple - available from Thompson & Morgan.
Penstemon 'Blackberry' a hardy perennial with glossy, semi-evergreen foliage that produces bell-shaped flowers in a rich shade of purple from June onwards. Height to 30in (75cm). Available from Thompson & Morgan.
Penstemon Blackbird bears deep purple-pink flowers with white striped throat. Long flowering season. Height to 28in (70cm) tall.
Penstemon campanulatus is a hardy shrubby plant with dull green, lance-shaped leaves. Erect spires of bell-shaped flowers of pink, purple or violet in summer. Height to 24in (60cm). Good cultivars include: 'Evelyn' with pink blooms and 'Garnet' with wine-red flowers.
Penstemon digitalis (beardtongue) is a bushy clump-forming hardy perennial with strong, erect stems, holding clusters of bell-shaped flowers. Height and spread to 18in (45cm). Good cultivars include 'Husker Red' with red foliage and pink-white flowers. Available from Thompson & Morgan.
Penstemon Flamingo is a large flowering strain with cherry-pink flowers and a striped white throat.
Penstemon Garnet is a free flowering strain with carmine red tubular flowers throughout the summer. Height to 3ft (90cm). Available from Thompson & Morgan.
Penstemon heterophyllus (bunchleaf) is a shrubby form that produces upright, branching stems, bearing wide-mouthed tubular flowers in shades of blue, purple and magenta. Height to 36in (90cm). Good cultivars include 'Electric Blue' with long-lasting intensely blue flowers from June to October. Height and spread to 24in (60cm) - available from Thompson & Morgan. The variety 'True Blue' is a pretty blue Penstemon with green and grey tinged foliage - available from Thompson & Morgan.
Penstemon 'Husker's Red' has attractive red foliage and white flowers with a tint of pink.
Penstemon x hybrida 'Lilac Frost' one of the best winter-hardy forms, producing bushy mounds of deep green foliage, topped by pretty bicoloured lilac and white blooms. Available from Thompson & Morgan.
Penstemon King George bears large scarlet flowers with a striped throat and wide mouth.
Penstemon 'Miniature Bells' produces lovely miniature bells in pink, purple and rose shades, complemented by dwarf attractive blue-green foliage. Long flowering period. Available from Thompson & Morgan.
Penstemon newberryi (mountain pride) is a hardy alpine form that produces shrubby mounds of dark green leathery leaves, covered with tiny red tubular flowers in summer. Height and spread to 12in (30cm).
Penstemon Pensham Czar is a long flowering form with beautiful mauve tubular blooms with a central white throat on upright flower stems. Available from Thompson & Morgan.
Penstemon 'Pensham Plum Jerkum' is a hardy perennial with semi-evergreen foliage and attractive plum coloured bell-shaped flowers. Height 30in (75cm), spread 18in (45cm). Available from Thompson & Morgan.
Penstemon pinifolius is a hardy alpine form that produces dense clusters of bright green, needle-like foliage. Tiny, vivid scarlet tubular flowers appear in July-August. Height to 6in (15cm), spread 9in (22cm).
Penstemon Snow Storm is a white bedding variety with pure white flowers.
Penstemon Sour Grapes is a large-leaved variety with purple flushed green flowers, borne from midsummer to mid-autumn. A beautiful evergreen that does particularly well in a sheltered spot or even on the patio.
Penstemon 'Strawberries & Cream' is a popular hardy perennial with glossy, semi-evergreen foliage and white trumpet shaped flowers in summer, with delicately speckled throats. Height to 30in (80cm). Available from Thompson & Morgan.
Penstemon 'Sweet Cherry' is a compact form with bright red, bell-shaped, showy blooms with pure white throats, that rise in spires above a mound of semi-evergreen foliage. Height and spread to 24in (60cm). Available from Thompson & Morgan.
Penstemon Wedding Day is an attractive variety with pure white flowers, blushed pink in bud for added interest.