Mountain Penstemon in the Landscape
Stephen Love, University of Idaho
Scientfic Name: Penstemon montanusCommon Name: Mountain Penstemon
Description: Mountain penstemon is a long-lived perennial that dies back to the ground during winter and emerges from the roots in the spring. The plant is small in stature, usually only 8 to 10 inches tall. The branches are thin, supple, and ascending to decumbent. The leaves are very attractive, triangular shaped, glistening gray-green, and often tinted red. The leaves are distributed full length along the flowering stems. The flowers are very large, tubular, and deeply lobeed. Flower color is deep lavender. The bloom period lasts approximately 6 weeks and recurs later in the season if plants are dead-headed. Mountain penstemon is a good subject for the front of a water-conserving bed, border, or rock garden.
Native Habitat: Found at high elevations in Idaho, Montana, Wyoming, and the Wasatch Front of Utah. Grows on steep, loose talus slopes where it has the ability to thrive under conditions of sloughing and moving rock. Commonly grows alone or in the presence of scattered low forbs. Found at elevations of 6,900 to 11,500 feet.
Cultural Requirement
Soil: Grows best in gravelly, well-drained soils. Tolerates a wide range of soil pH.
Moisture Tolerance: Moderately xeric. Requires some supplemental irrigation to remain attractive throughout the season.
Sun/Shade/Preference: Blooms best in full sun but tolerates part-shade. Plant health is enhanced in hot climates with the presence of afternoon shade.
Transplanting: Tolerates transplanting with occasional losses, both from pot to pot and from pot to garden. Plants develop adequately in small diameter pots, but do best if the time in the pot is limited.
Propagation: Best from seed. Seed may show inconsistent germination and requires an 8-12 week stratification period. Some success can also be had with root and stem cuttings.
Maintenance (pruning, fertilization, deadheading, division, irrigation, etc): Dead-heading will often encourage prolonged bloom or rebloom. Supplemental irrigation is needed (four to six times during each summer) to keep plants actively growing and attractive. Occasional fertilization may help plants perform at their best.
Insect, disease, or other problems: Mountain penstemon has no serious insect or disease problems.
Landscape Value
Use in the Landscape: Mountain penstemon is a low, mounding plant. It is best used in front of larger plants or in small beds and borders. Mountain penstemon is beautiful in a rock-strewn alpine rock garden. It is especially effective when mixed with plants that complement the early spring bloom period. It can be used in either naturalized or formal designs.
Foliage: The leaves are gray-green, glisten in the sun, and are often fringed or highlighted with red. The plants produce no basal leaf mat and the leaves grow only on the flowering stems. The plants have a leafy look, even when in flower.
Flower: The flowers grow at the ends of flexible, leafy stems. They are usually a translucent, medium to dark lavender, but occasionally come in hues of blue. The flowers are large, tubular, and have large front lobes.
Timing: May - August.
Color: Lavender.
Fruit: A globular capsule, with sharp, stiff lobes on top. The capsule grows closely attached and parallel to the stem. Each capsule holds numerous seeds.
Form: Loosely mounded.
Texture: Moderately fine.
Ultimate Size: In or out of bloom – 8 to 10 inches tall and 10 to 12 inches wide.
Rate of Growth: Moderately slow. The plants seldom bloom the first year. The plants increase in width and number of flowering stems as they age.
Suggested Plant Partners: Plant mountain penstemon with low-growing forbs and grasses. Blue fescue (Festuca idahoensis) is a great complimentary plant. Other good partners include Oenothera caespitosa, Antennaria rosea, Erigeron compositus, Erigeron glaucus, Eriogonum ovalifolium, Geranium viscosissimum, Melampodium leucanthum, Mondardella odoratissima, Townsendia incana, and Zauschneria garrettii.
Availability: Limited availability. Native plant nurseries occasionally carry Penstemon montanus as potted plants. Seed can be purchased from the American Penstemon Society or from some native plant seed suppliers.
Cultivars: None.
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