Penstemon digitalis 'Onyx and Pearls'

Common Name: beardtongue 
Type: Herbaceous perennial
Family: Plantaginaceae
Zone: 3 to 8
Height: 3.00 to 3.50 feet
Spread: 3.00 to 3.50 feet
Bloom Time: April to June
Bloom Description: Pale purple to nearly white
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Rain Garden
Flower: Showy, Good Cut
Leaf: Colorful
Attracts: Hummingbirds, Butterflies
Tolerate: Deer, Drought, Clay Soil, Dry Soil


Best grown in average, dry to medium moisture, well-drained soil in full sun. Tolerant of occasional drought and inundation once established. Can be grown in clay soils but avoid overly wet, poorly drained conditions.

'Onyx and Pearls' requires full sun to develop and maintain its dark purple leave coloration.

Noteworthy Characteristics

Penstemon digitalis, commonly called foxglove beardtongue, is a clump-forming, Missouri-native perennial which typically grows 3-5' tall and occurs in prairies, fields, wood margins, open woods and along railroad tracks. Features white, two-lipped, tubular flowers (to 1.25" long) borne in panicles atop erect, rigid stems. Flowers bloom mid-spring to early summer and are attractive to hummingbirds, butterflies, and other pollinators. Basal leaves are elliptic and stem leaves are lance-shaped to oblong.

Genus name comes from the Greek words penta meaning five and stemon meaning stamen in reference to each flower having five stamens (four are fertile and one is sterile).

Specific epithet comes from the Latin digitus meaning finger for flowers that look like the finger of a glove.

Penstemon is sometimes commonly called beard tongue because the sterile stamen has a tuft of small hairs.

'Onyx and Pearls' is a cold-hardy, dark-leaved selection of foxglove beardtongue that features pale purple to nearly white blooms on upright flowering stalks. Mature clumps will reach up to 3.5' tall with a similar spread. The tubular flowers are held on terminal, branched panicles above the dark purple foliage. This cultivar was selected from second generation, self-crossed seedlings of Penstemon digitalis 'Pocahontas'. This plant is protected by patent number PP32613.


Root rot can occur in wet, poorly-drained soils. Leaf spots are occasional problems. Can spread somewhat aggressively in a garden setting. Deer tend to avoid this plant.


Mass in sunny borders, rain gardens, wild gardens, native plant gardens or naturalized areas. Excellent for fresh cut flower arrangements.