Common Name: beardtongue
Type: Herbaceous perennial
Family: Plantaginaceae
Native Range: Wyoming, Colorado, Utah
Zone: 4 to 7
Height: 0.25 to 0.25 feet
Spread: 0.25 to 0.75 feet
Bloom Time: May to July
Bloom Description: Lavender-purple
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Ground Cover
Flower: Showy
Tolerate: Deer
Culture
Easily grown in average, dry to medium, well-drained soils in full sun. Superior soil drainage is the key to growing this plant well. Avoid wet, poorly-drained soils.
Noteworthy Characteristics
Penstemon caespitosus, commonly called mat penstemon, is a mat-forming perennial that typically forms low tufts to 2” tall and spreads by slender, prostrate, creeping stems. It is native to the western US states of Wyoming, Colorado, Utah, and Arizona where it is found growing in rocky shrublands, and pinyon-juniper woodlands. Stems are clad with tiny, narrow, linear to spatulate leaves (to 1/2” long). Lavender-purple, two-lipped flowers (to 1/4” long) have lighter colored throats with purple-red streaks and a densely hair, yellow, sterile stamen (staminode).
The genus name Penstemon likely comes from the Latin paene meaning "almost" or "nearly" and the Greek stemon meaning "stamen". The name may also comes from the Greek penta meaning "five" and stemon meaning "stamen". Both refer to the fifth, sterile stamen (staminode) that characterizes members of this genus.
The specific epithet caespitosus means "growing in tufts", in reference to the plant habit.
The common name mat penstemon refers to the growth habit of this species.
Problems
No serious insect or disease problems. Root rot may occur in wet, poorly-drained soils.
Uses
Sunny areas of rock gardens or native plant gardens.