Penstemon gloxinioides (Beardtongue) — Bushy, upright, semi-woody at the base

Overview

Penstemon gloxinioides 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 gloxinioides grows best in full sun, and tolerates most soils and neutral to alkaline pH. Its UK hardiness is rated H3-H5.

About

Penstemon gloxinioides is a perennial in the Plantaginaceae with an upright, well-branched habit and stems that become semi-woody at the base. It carries narrow, glossy leaves that are semi-evergreen to evergreen and flowers from June to September. Plant in full sun on light, fertile, free-draining loam or sand with a neutral to alkaline pH. Avoid winter-wet situations, as prolonged dampness at the roots is the main cause of failure.

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 gloxinioides is a perennial member of the Plantaginaceae producing upright stems with narrow, glossy foliage that remains semi-evergreen in mild winters and a long flowering season from June to September. Stems develop a semi-woody base with age, giving the plant structure between seasons. Place it in a sunny, sheltered position on a south- or west-facing aspect where roots stay dry through winter. It favours light, fertile soils—free-draining loam or sand—and prefers neutral to alkaline conditions. Winter wet causes most losses, so good drainage is essential and sites exposed to driving wind or persistent cold should be avoided. In UK terms its hardiness spans H3 to H5 (borderline to hardy), so treat plants in colder, exposed districts more cautiously and choose the warmest, driest spot available. Use Penstemon gloxinioides towards the front or centre of a sunny border, on a dry bank or any well-drained, south- or west-facing site where its summer display can be seen. The narrow, mid–dark green leaves retain presence through mild winters and help the plant hold a neat outline outside the flowering months.

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 gloxinioides 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

Care notes

Pruning and caring for Penstemon gloxinioides

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 gloxinioides?

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 gloxinioides?

Penstemon gloxinioides prefers full sun. It suits sheltered positions.

What soil does Penstemon gloxinioides need?

Penstemon gloxinioides 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 gloxinioides?

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 gloxinioides hardy in the UK?

Penstemon gloxinioides 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 gloxinioides?

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 →