Penstemon (10)

Penstemon is a very large genus that is easy to recognize, but not so easy to identify individual species. The flowers are tubular with two lips; the upper lip is two-lobed and the lower is three-lobed. The leaves are opposite without stalks. The flowers can be blue, purple, lavender, pink or red. See Beardtongue, Scarlet Penstemon, Mat Penstemon, Palmer's Penstemon and other Penstemon in Blue Long Clusters. There is a great deal of passion about Penstemon amongst horticulturists on the Internet but the best key I found was from 1915 by Francis Whittier Pennell. Scrophulariaceae of the Central Rocky Mountains. It is charming to read his introduction of traveling along on the Rio Grande Railroad to make his collections. So much has changed and yet so little in 100  years. The American Penstemon Society also has a lot of information.

Penstemon strictus

Rocky Mountain Penstemon
Penstemon strictus

Family:Plantain (Plantaginaceae)
AKA: One-sided Penstemon, Rocky Mountain Beardtongue
Photo taken on: July 6, 2004
Location: Almont, CO
Life Zones: Foothills to subalpine
Habitat: Meadows, slopes, roadsides

Grows to 3 feet tall in showy masses. Flowers range from pale lavender to purple and grow on one side of the stem. It is the most common and tallest Penstemon in the Gunnison Valley.

Penstemon strictus

 

 

Rocky Mountain Penstemon has hairs on the anthers inside the flower which distinguishes it from the similar looking Grand Mesa Penstemon below.

Penstemon mensarum

Grand Mesa Penstemon
Penstemon mensarum

Family: Plantain (Plantaginaceae)
AKA: Tiger Beardtongue
Photo taken on: July 4, 2004
Location: Poverty Gulch, GV, CO
Life Zones: Montane to subalpine
Habitat: Disturbed areas, trail-sides

Grows to 2 feet with glossy deep-green leaves. Flowers are an intense electric blue. It is quite common in Mesa, Delta and Gunnison counties but not found in the wild elsewhere.

Penstemon saxosorum

Upland Penstemon
Penstemon saxosorum

Family: Plantain (Plantaginaceae)
AKA:
Photo taken on: June 27, 2004
Location: Almont, CO
Life Zones: Montane
Habitat: Gravelly, rocky slopes

Grows 4" to 20" high with smooth, hairless, narrow, lance-shaped leaves. The deep blue flowers are 1" long and grow all around the stem compared to Rocky Mountain Penstemon.

Penstemon angustifolius

Narrow-Leaved Penstemon
Penstemon angustifolius

Family: Plantain (Plantaginaceae)
AKA: Skyblue Penstemon, Broadbeard Beardtongue
Photo taken on: May 29, 2016
Location: Wet Mountains, Eastern CO
Life Zones: Plains and foothills
Habitat: Sandy areas, vacant lots, roadsides

Grows to 20" with stout smooth stems and fleshy, narrow leaves with a prominent mid-rib. Stems and leaves are light green and hairless. The flowers are lavender to bright blue and grow all around the stem. The sterile stamen has orange hairs on its tip.

Penstemon glaber

Sawsepal Penstemon
Penstemon glaber

Family: Plantain (Plantaginaceae)
AKA: Western Smooth Beardtongue
Photo taken on: July 20, 2009
Location: Wet Mountains, Eastern CO
Life Zones: Foothills to montane
Habitat: Open woods, gravelly soils

Can grow to 24" with large leathery bright green leaves opposite on the stem. The blue flowers have pink throats and grow on one side of the stem. The sepals are rounded with a short, sharp tip.

Penstemon glaber has several varieties. They all have bright green, hairless leaves clasping the stem, some are thicker and leathery, shape varies from lance-shaped to almost triangular, some smooth-edged others wavy. Below are two varieties.

Penstemon glaber var. alpinus

Alpine Sawsepal Penstemon
Penstemon alpinus (P. glaber var. alpinus)

Family: Plantain (Plantaginaceae)
AKA: Alpine Penstemon
Photo taken on: July 5, 2013
Location: Kenosha Pass, CO 285
Life Zones: Foothills to subalpine
Habitat: Gravelly, disturbed soil, roadsides

Grows 4" to 18" east of the Continental Divide but not in the alpine zone, despite its name. Leaves are smooth, lance-shaped and medium green. Showy flowers, about an 1" long, grow on one side of the thick stems. The sepals are oval-shaped and pointed. The sterile stamen is slender and not lobed.

Penstemon glaber var. brandegee

Brandegee's Penstemon
Penstemon brandegeei (P. glaber var. brandegee)

Family: Plantain (Plantaginaceae)
AKA:
Photo taken on: July 10, 2015
Location: SR 165, San Isabel NF, CO
Life Zones: Foothills to montane
Habitat: Gravelly, disturbed soil, road cuts

Grows to 2½ feet, very robust and stockier than P. glaber and P. alpinus. Leaves are broadly lance-shaped and clasp the stem. Flowers are showy, intense blue-purple crowded on one side of the stems and 1½" long. Sepals are oval with a long tip. The sterile stamen is stout with two lobes and sticks out of the throat. Nobody mentions the crinkly-edged leaves.

Penstemon hallii

Hall's Penstemon
Penstemon hallii

Family: Plantain (Plantaginaceae)
AKA: Hall's Beardtongue
Photo taken on: July 14, 2012
Location: Paradise Divide, GV, CO
Life Zones: Alpine
Habitat: Tundra, rocky, gravelly soils

Grows to 8" with bluish-purple flowers on one side of the stem. Leaves are narrow and entire. It only grows in central and southwest Colorado.

Penstemon virens

Front Range Penstemon
Penstemon virens

Family: Plantain (Plantaginaceae)
AKA: Front Range Beardtongue, Blue Mist Penstemon
Photo taken on: June 15, 2014
Location: Wet Mountains, Eastern CO
Life Zones: Foothills to montane
Habitat: Gravelly areas, wooded slopes

Grows to 12" high from mats of bright green, hairless leaves. Flowers are bright blue to blue violet with a pale throat with maroon stripes and are ½" long. The outside of the flowers has hairs and the beardtongue has orange hairs. Flowers grow all around the stem. It only grows east of the Divide.

Penstemon unilateralis

Oneside Penstemon
Penstemon unilateralis (Penstemon virgatus var. asa-grayi)

Family:Plantain (Plantaginaceae)
AKA: Oneside Beardtongue
Photo taken on: July 18, 2016
Location: CO SR 114, S of Cochetopa Pass
Life Zones: Foothills to montane
Habitat: Shady slopes, roadsides

Grows to 2 feet with flowers on one side of the stem. Leaves are long narrow and folded inwards. Flowers are broad with a white throat and strong purple lines, nectar guides. The stamens are white, curved and hairless. The sterile stamen is white, hairless, broader at the tip and extends a little from the throat. This differentiates it from some of the similarly patterned Beardtongues.

Blue/Purple Long Clusters