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Penstemon cobaea

cobaea beardtongue

Plantaginaceae South-central United States

Attracts Pollinators Attracts Hummingbirds Deer Resistant Drought Tolerant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 5–8

Overview

Penstemon cobaea is a herbaceous perennial in the plantain family, native to the south-central United States, growing 1-2.5 feet (0.3-0.75 m) tall in an upright clump from a woody crown. The thick, glossy, dark green leaves are oval to lance-shaped, 2-4 inches (5-10 cm) long, with toothed edges, the lower ones stalked and the upper ones clasping the stem. In late spring, stout stems carry large, inflated, tubular flowers 1.5-2 inches (3.8-5 cm) long in open clusters, ranging from white and pale lavender to deep purple, with darker purple lines inside the wide, bell-like throat. The broad throat is wide enough to admit large bees, which pollinate the flowers. It is hardy in USDA zones 5-8 and grows on dry prairies, rocky hillsides, and limestone glades. The plant grows on lean, sharply drained soil and is short-lived in rich or wet ground, often persisting three to four years before fading. Bloom lasts only a few weeks in late spring.

Native Range

Penstemon cobaea is native to the south-central United States, centered on Kansas, Oklahoma, Texas, Missouri, and Arkansas, with scattered populations eastward. It grows on dry prairies, rocky open hillsides, roadsides, and limestone or sandy glades.

Suggested Uses

Used in prairie and native plant gardens, rock gardens, and dry borders on lean soils. The large flowers draw bumblebees and other native bees, and the plant suits naturalized meadow and pollinator plantings.

How to Identify

Identify cobaea beardtongue by its large, inflated, bell-like tubular flowers 1.5-2 inches (3.8-5 cm) long in white to purple with dark interior lines, set on stout stems above thick, glossy, toothed leaves. The wide throat and large flower size separate it from narrower-flowered prairie penstemons such as P. tubaeflorus. The fifth stamen, the bearded staminode, gives the beardtongues their name.

Appearance

Size & Dimensions

Height1' - 2'6"

Width/Spread1' - 1'6"

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~4 weeks

Spring

Flowering runs from April through June, mainly in May. Open clusters of large tubular flowers open along stout upright stems for a few weeks. Large bees, including bumblebees, enter the wide throats to pollinate the flowers, and dry seed capsules follow.

Detailed Descriptions

Flower Description

white to purple

Foliage Description

glossy dark green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.5 - 8.0(Alkaline)

357912

Soil Types

rocky loam sand chalk

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun to light shade on dry, rocky, sharply drained soils, including limestone and sandy ground. A soil pH of 6.5-8.0 suits the species, which handles alkaline soil well. Established plants are drought tolerant and need no summer water. Rich, moist, or poorly drained soil shortens its life and causes crown rot. Good drainage and lean soil extend its life span. It self-sows where the ground stays open, which helps the planting persist as older plants fade.

Pruning

Spent flower stalks can be cut back after bloom to tidy the clump, or left to ripen and drop seed for self-sowing. The basal foliage is left in place through winter. No other pruning is needed.

Pruning Schedule

summer

Container Growing

✓ Suitable for container growing

Minimum container size: 2 gallons

✓ Toxicity

Non-toxic