Penstemon cyananthus (Blue Penstemon) — perennial

Overview

Penstemon cyananthus is a perennial in the genus Penstemon, part of the Plantaginaceae family. Penstemon cyananthus grows best in full sun, and tolerates well-drained and sandy or rocky soils and neutral to slightly alkaline pH. Suggested uses include rock gardens, xeriscaping and wildflower gardens. It is native to Idaho, Montana, Utah and Wyoming.

About

Penstemon cyananthus is a species of the genus Penstemon in the family Plantaginaceae, producing the tubular, two-lipped flowers and prominent staminode typical of the group. It flowers from June to September. Leaves are typically arranged opposite and the fruits are dry seed capsules. The sterile, often bearded staminode is a useful identification feature in the throat of the flower.

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 cyananthus belongs to the genus Penstemon, a large group of North American plants in the family Plantaginaceae that range from northern Canada to Central America. The genus is commonly referred to as penstemons or beardtongues; members share a fused corolla that forms a two-lipped tube and an infertile stamen called a staminode. Floral structure is central to both identification and propagation: the two-lipped, tubular corolla and bearded staminode are diagnostic, and after flowering the plant sets seed in capsules that can be collected. Flowering runs from June to September, giving an extended period when seed can be examined for maturity and harvested for sowing. Growers working with penstemons typically treat each species on its own provenance and performance, since habits and tolerances vary across the genus. For propagation, allow capsules to fully ripen on the plant before opening; clean, dry seed stores well for later sowing. When assessing examples in cultivation, check the throat of the flower for the bearded staminode—that feature reliably confirms Penstemon cyananthus when it is in bloom.

Growing conditions

Best soil and position for Penstemon

Sunlight: full sun
Soil type: well-drained, sandy or rocky
Soil pH: neutral to slightly alkaline
Soil moisture: dry to medium
Aspect: south-facing
Exposure: open

Plant details

Penstemon cyananthus size, habit and characteristics

Plant type: perennial
Suggested uses: rock gardens, xeriscaping, wildflower gardens
Native to: Idaho, Montana, Utah, Wyoming

Care notes

Pruning and caring for Penstemon cyananthus

Cultivation: Prefers well-drained soil and full sun; drought tolerant once established
Pruning: Deadhead spent flowers to encourage more blooms; cut back after flowering to maintain shape
Propagation: seed, cuttings

Frequently asked questions

How do I grow Penstemon cyananthus?

Prefers well-drained soil and full sun; drought tolerant once established.

Where is the best place to plant Penstemon cyananthus?

Penstemon cyananthus prefers full sun. It suits open positions.

What soil does Penstemon cyananthus need?

Penstemon cyananthus grows best in well-drained and sandy or rocky soil. It prefers neutral to slightly alkaline soil. Aim for soil that stays dry to medium.

How do I prune Penstemon cyananthus?

Deadhead spent flowers to encourage more blooms; cut back after flowering to maintain shape.

How do I propagate Penstemon cyananthus?

Seed, cuttings.

More in the Penstemon genus

Browse all Penstemon →