Species Native to Missouri
Common Name: large beardtongue
Type: Herbaceous perennial
Family: Plantaginaceae
Native Range: North Dakota to Wyoming, Texas and Illinois
Zone: 3 to 9
Height: 2.00 to 4.00 feet
Spread: 1.00 to 1.50 feet
Bloom Time: May to June
Bloom Description: Lavender blue
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize
Flower: Showy
Tolerate: Deer
Culture
Best grown in gritty, dry to medium, well-drained soils in full sun. Avoid moist, poorly-drained clay soils. Do not overwater. Full sun may help avoid onset of root rot. Plants may be cut back to basal foliage after bloom to improve appearance of the planting. May be grown from seed. Plants will self-seed in optimum growing conditions.
Noteworthy Characteristics
Penstemon grandiflorus, called large beardtongue, or large-flowered beardongue, is a herbaceous perennial native to sand prairies, tallgrass prairies, loess hills, and other open, grassy habitats in the Great Plains and portions of the Midwest United States. Mature plants typically grow 2-4' tall and are noted for their upright growth habit, large, tubular, blue-lavender flowers, and silvery foliage. Flowers (to 2” long) bloom in upright, open racemes in late spring. Foliage consists of thick, toothless, opposite, clasping, blue-green leaves, with the basal leaves obovate and the stem leaves rounded to elliptic.
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 grandiflorus means "large-flowered".
Problems
Leaf spots, rusts and rots may occur. Plants tend to be short-lived. Some gardeners consider the plants to be inappropriate for conspicuous border areas because the bloom period is short and is followed by somewhat unattractive die back.
Uses
Rock gardens, meadows, native plant gardens. Effective when massed. Also may be used in borders.