Penstemon campanulatus (bellflower beardtongue) — Bushy, upright, semi-woody at the base

Overview

Penstemon campanulatus 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 campanulatus grows best in full sun, and tolerates most soils and neutral to alkaline pH. Its UK hardiness is rated H3-H5. Suggested uses include rock gardens, borders and containers. It is native to Mexico.

About

Penstemon campanulatus is a perennial in the Plantaginaceae with narrow, glossy, mid to dark green foliage and an upright, multi-stemmed habit with semi-woody lower shoots. It favours full sun on light, fertile, free-draining loam or sand and tolerates neutral to alkaline soils. Sit it on a south- or west-facing, sheltered spot because winter wet is the most frequent cause of loss. Flowering runs from June to September, extending summer interest in borders and containers.

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 campanulatus originates from Mexico and is grown for its semi-evergreen, narrow glossy leaves and upright, semi-woody habit. As a perennial in the Plantaginaceae it establishes as a clump-forming plant that performs best in warm, well-lit exposures rather than in shade. Give it a sunny, sheltered position on light, fertile, free-draining loam or sand with a neutral to alkaline pH. It requires full sun and dislikes winter waterlogging; poor drainage is the single biggest threat to overwintering. In UK hardiness terms it spans H3–H5, meaning it ranges from borderline in the coldest sites up to reliably hardy in milder, protected gardens. Use Penstemon campanulatus in rock gardens, mixed sunny borders or planted in containers where free drainage can be ensured. Its flowering season from June to September delivers sustained summer colour, so place it where the blooms will be visible through the warmer months and where winter wet is least likely to accumulate.

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 campanulatus 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
Suggested uses: Rock gardens, borders, containers
Native to: Mexico

Care notes

Pruning and caring for Penstemon campanulatus

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 campanulatus?

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 campanulatus?

Penstemon campanulatus prefers full sun. It suits sheltered positions.

What soil does Penstemon campanulatus need?

Penstemon campanulatus 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 campanulatus?

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 campanulatus hardy in the UK?

Penstemon campanulatus 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 campanulatus?

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

Browse all Penstemon →