Overview
Penstemon barbatus is a bushy, upright, semi-woody at the base perennial in the genus Penstemon, part of the Plantaginaceae family, with semi-evergreen or evergreen; narrow, glossy, mid to dark green foliage. Penstemon barbatus grows best in full sun, and tolerates most soils and neutral to alkaline pH. Its UK hardiness is rated H3-H5. It is native to Mexico & S USA.
About
Penstemon barbatus is a perennial with multi-stemmed, upright growth and semi-woody bases that produces spikes of tubular flowers from June to September. Leaves are narrow, glossy and mid to dark green and remain semi-evergreen in milder sites. It favours a south- or west-facing, sheltered position in light, free-draining soil. Winter waterlogged soil is the common cause of losses.
Wikipedia contributors, CC BY-SA 4.0 — Penstemon barbatus
About the genus
Penstemon, the beardtongues, is a large genus of roughly 280 species of flowering plants native to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America. As well as being the scientific name, penstemon is also widely used as a common name for all Penstemon species alongside beardtongues.
Wikipedia contributors, "Penstemon", CC BY-SA 4.0 — Penstemon
In the garden
Penstemon barbatus is a perennial native to Mexico and the southern United States, producing upright flowering stems topped with spikes of tubular scarlet flowers through the summer and into early autumn (June to September). The foliage is narrow, glossy and mid to dark green and can remain semi-evergreen where winters are mild. Position the plant in full sun on light, fertile, free-draining loam or sand with a neutral to alkaline pH. Avoid heavy, moisture-retentive soils; winter wet is the principal threat to the crown. Give a sheltered, south- or west-facing aspect to reduce exposure to cold winds and waterlogging. Its UK hardiness is H3–H5, which translates as borderline to hardy: it will persist in sheltered sites across much of the UK but is less reliable where winters are very exposed or soils remain wet. Use Penstemon barbatus in sunny, well-drained borders or gravel beds where its upright flowering spikes can be seen at eye level and benefit from summer sun. Its long flowering season from June to September extends summer interest into early autumn and helps fill late-season gaps in the border.
Growing conditions
Best soil and position for Penstemon
- Sunlight
- Full sun
- Soil type
- Light, fertile, free-draining loam or sand
- Soil pH
- Neutral to alkaline
- Soil moisture
- Well drained; winter wet causes most losses
- Aspect
- South or west facing
- Exposure
- Sheltered
- UK hardiness
- H3-H5
Plant details
Penstemon barbatus size, habit and characteristics
- Plant type
- Perennial
- Habit
- Bushy, upright, semi-woody at the base
- Foliage
- Semi-evergreen or evergreen; narrow, glossy, mid to dark green
- Native to
- Mexico & S USA
Care notes
Pruning and caring for Penstemon barbatus
- Cultivation
- Drainage and shelter decide whether a penstemon is perennial or annual in your garden. Plant in spring rather than autumn so the roots establish before winter, and leave the top growth standing until spring as crown protection. Regular deadheading is what sustains the extraordinarily long season. Given the modest hardiness of most cultivars, taking cuttings every summer is sensible insurance.
- Pruning
- Leave stems intact over winter, then cut back to low healthy buds in mid-spring once frosts have passed. Deadhead continuously through summer, cutting spent spikes to a side shoot.
- Propagation
- Semi-ripe cuttings taken in late summer root quickly and are the standard method - and the usual replacement for winter losses. Species can be raised from seed.
- Pest resistance
- Slugs take young spring shoots; capsid bug and eelworm occur but are uncommon.
- Disease resistance
- Powdery mildew and leaf spot appear on crowded plants. Root rot follows winter waterlogging.
Frequently asked questions
How do I grow Penstemon barbatus?
Drainage and shelter decide whether a penstemon is perennial or annual in your garden. Plant in spring rather than autumn so the roots establish before winter, and leave the top growth standing until spring as crown protection. Regular deadheading is what sustains the extraordinarily long season. Given the modest hardiness of most cultivars, taking cuttings every summer is sensible insurance.
Where is the best place to plant Penstemon barbatus?
Penstemon barbatus prefers full sun. It suits sheltered positions.
What soil does Penstemon barbatus need?
Penstemon barbatus is adaptable and grows happily in most soil types, including light, fertile and free-draining loam or sand. It prefers neutral to alkaline soil. Aim for soil that stays well drained; winter wet causes most losses.
How do I prune Penstemon barbatus?
Leave stems intact over winter, then cut back to low healthy buds in mid-spring once frosts have passed. Deadhead continuously through summer, cutting spent spikes to a side shoot.
Is Penstemon barbatus hardy in the UK?
Penstemon barbatus has an RHS hardiness rating of H3, meaning it is half-hardy, tolerating -5 to 1°C, and may need winter protection in colder areas.
How do I propagate Penstemon barbatus?
Semi-ripe cuttings taken in late summer root quickly and are the standard method - and the usual replacement for winter losses. Species can be raised from seed.
More in the Penstemon genus
- Penstemon 'Raven'Beardtongues
- Penstemon campanulatusbellflower beardtongue
- Penstemon campanulatus 'Andenken an Hahn'Penstemon
- Penstemon campanulatus 'Evelyn'Beardtongue
- Penstemon campanulatus 'Garnet'Penstemon
- Penstemon campanulatus 'Hidcote Pink'Beardtongue
- Penstemon campanulatus 'Pink Endurance'Beardtongue
- Penstemon cyananthusBlue Penstemon
