Low Beardtongue

Scientific Name: Penstemon humilis Nutt. ex A. Gray

Plant Guide

Alternate Names

Low beardtongue, Penstemon humulis ssp. humilis, Penstemon humilis ssp. obtusifolius, Penstemon humilis ssp. brevifolius

Uses

Grazing/rangeland: 'Cedar' Palmer penstemon (Penstemon palmeri) and 'Bandera' Rocky Mountain penstemon (Penstemon strictus) are the only released penstemons noted to have any forage value. 'Cedar' leaves stay green throughout the growing season providing some forage value. All other varieties are considered fair to poor palatability and considered to be only incidental forage value. All species provide diversity to the seeded plant community. Erosion control/reclamation: All species are mentioned for their value in mixes for erosion control and beautification values. Wildlife: Penstemons are considered desirable forages for deer, antelope, and birds either as herbage or seed. They may also provide some cover for selected small bird species. They provide diversity to the plant community. Jeanne R. Janish Cronquist (1984) © The New York Botanic Garden

Status

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values.

Description

General: Figwort Family (Scrophulariaceae). Penstemon or beardtongue species are perennial forbs or sub-shrubs to shrubs with attractive flowers. They are short to long-lived. Low beardtongue is recognized as having three subspecies: Penstemon humulis ssp. humilis, Penstemon humilis ssp. obtusifolius, and Penstemon humilis ssp. brevifolius. Cronquist et al. (1984) provides a key to separating these subspecies, plus provides a short discussion of their ranges and characteristics. Low penstemon is an herbaceous to woody subshrub perennial from 0.5 to 2.5 (sometimes 3.5) dm tall with well-developed basal leaves, usually forming mats. Generally, penstemons have opposite, entire, or toothed leaves. They have several stalked flowers or flower clusters that are borne in the axils of the upper leaves or leaf-like bracts. The tubular corolla is strongly to distinctly two-lipped at the mouth with a two-lobed upper lip and a three-lobed lower lip. There are 4 anther-bearing (fertile) stamens and a single sterile stamen or staminodia that is often hairy at the tip. The fruit is a many-seeded capsule.

Distribution

Low penstemon is found in the western U.S. from New Mexico to California and north to Washington. Penstemons are common to the western United States. Except for one minor species, the genus Penstemon does not occur naturally outside of North America. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Establishment

Adaptation: Penstemons do best on well-drained soils. Most ecotypes do well on infertile, disturbed soils. They have excellent cold winter and drought tolerance. They will tolerate weakly saline to weakly acidic sites. They are usually found in open areas, but will tolerate semi-shaded conditions. They are not tolerant of fire, but are fire resistant due to leaves staying green with relatively high moisture content during the fire season. Low penstemon is found from sagebrush valleys and pinyon-juniper woodlands to openings in montaine forests and alpine tundra (Cronquist et al. 1984). Planting: These species should be seeded with a drill or broadcast at a depth of 1/4 inch or less into a firm seedbed. Ideal seeding depth is 1/8 inch. Penstemons are not recommended for single species seeding. The full seeding rate (not recommended) for these forbs-shrubs is 1.5 to 3 pounds Pure Live Seed (PLS) per acre or 20 to 26 PLS per square foot (varies somewhat by species). When used as a component of a mix, adjust to percent of mix desired. For mined lands and other harsh critical areas, doubling the seeding rate component of penstemon is not required. The best seeding results are obtained from seeding in very early spring (because of grass component of mix) on heavy to medium textured soils and in late fall on medium to light textured soils. Late summer (August - mid September) seeding is not recommended. Dormant fall seedings (preferred seeding period for penstemons) will pre-chill seed and reduce seed dormancy which is very strong in some species. Mulching, irrigation and weed control all benefit stand establishment. Seedling vigor is good, but not as good as most grasses. Germination may not occur until the second growing season. Flowering should not be expected until at least the second growing season. Stands may require weed control measures during establishment. Because penstemons are broadleaf, use of 2,4-D is not recommended. Mow weeds at or prior to their bloom stage. Grasshoppers and other insects may also damage new stands and pesticides may be needed.

Management

Growth of penstemons begins in early spring and flowers appear in May through July depending on species. Weed control and removal of very competitive species may improve chance of establishment. Damage from wildlife and rodents may occur and they may need to be controlled. Disease problems are minimal except under irrigation. Under irrigation, fusarium wilt can be a problem. Environmental Concerns: Penstemon species establish and spread slowly via seed distribution. They are not considered "weedy" or invasive species, but can spread into adjoining vegetative communities under ideal climatic and environmental conditions. They coexist with other native species and add biodiversity to those plant communities.

Seed Production

Penstemons should be seeded in at least 36-inch rows at the rate of 2.5 pounds PLS per acre to allow mechanical weed control. The use of weed barrier material may be an alternative to allow closer spacing. They should be seeded in late fall or early winter unless seed is stratified under cool moist conditions. "The Clearwater Selection" of alpine penstemon does not require stratification. Transplants by dividing the base of older plants or from greenhouse starts can also be successfully used to establish seed fields. Seed is generally harvested by hand stripping or by combine. Seed is mature when capsules are dry and seed is hard and dark in color. Flowering is indeterminate with mature capsules and flowers present at harvest period. Multiple harvest periods (by hand) may be necessary to maximize seed collection. Some seed will shatter once capsules open, but the capsule is upright and tends to hold seed very well. Seed can be separated from the capsule by use of a hammer mill or barley debearder followed by air screening. Cleaned seed should be allowed to dry and then stored in a cool dry area. An after-ripening period of 3 to 4 months is required. Seed retains viability for several years under these conditions. Cultivars, Improved and Selected Materials (and area of origin) Foundation and registered seed is available for each variety through the appropriate state Crop Improvement Association or commercial sources to grow certified seed. A number of penstemons are seeded primarily for soil stabilization on depleted, disturbed, and erosive areas for erosion control and as ornamentals. These include low penstemon (Penstemon humilis), Rydberg penstemon (Penstemon rydbergii), and thickleaf penstemon (Penstemon pachyphyllus). No cultivars releases are known to have have been made. Please check the PLANTS database for the names of other native penstemons in your state, then check with your area native plant nurseries for their availability. Contact your local Natural Resources

Conservation

Service (formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government.” The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”

References

Cronquist, A,, A,H, Holmgren, N,H, Holmgren, J,L, Reveal, & P,K, Holmgren 1984, Intermountain flora, Volume Four, Subclass Asteridae (except Asteraceae), The New York Botanical Garden, Bronx, New York, Crosswhite, F,S, 1967, Revision of Penstemon section Habroanthus (Scrophulariaceae), I: Conspectus, II: series Speciosi, and III: series Virgati, American Midland Naturalist 77:1,41, Holmgren, N,H, 1971, A new species of Penstemon from Nye Co,, Nevada, Aliso 7:351-356, ________, 1978a, An overlooked new species of Penstemon (Scropulariaceae from the Great Basin, Brittonia 30:334-339, ________, 1978b, Three new species of Penstemon (Scrophulariaceae from the Intermountain region, Brittonia 30:416-425, ________, 1979a, Use soil moisture sensors to measure the soil moisture of Low Beardtongue., Nomenclatural changes in some Intermountain penstemons (Scrophulariaceae), Brittonia 31:104-107, ________, 1979b, New penstemons (Scrophulariaceae) from the Intermountain region, Brittonia 31:217-242, ________, 1979c, Subgeneric and sectional names for Intermountain Penstemon (Scrophulariaceae), Brittonia 31:358-364, ________, 1980, A new Penstemon (Scrophulariaceae) from northwestern Arizona, Brittonia 32:326-329, Keck, D,D, 1932, Studies in Penstemon, A systematic treatment of the section Saccanthera, Univ, Calif, Publication in Botany 16:367-426, ________, 1937a, Studies in Penstemon IV, The section Ericopsis, Bulletin of the Torrey Botanical Club 64:357-381, ________, 1937b, Studies in Penstemon V, The section Peltanthera, American Midland Naturalist 18:790-829, ________, 1938, Studies in Penstemon VI, The section Autator, Bulletin of the Torrey Botanical Club 65:233-255, ________, 1940, Studies in Penstemon VII, The subsections Gairdneriani, Deusti, and Arenarii of the Graciles, and miscellaneous new species, American Midland Naturalist 23:594-616, ________, 1945, Studies in Penstemon-VIII, A cyto-taxonomic account of the section Spermunculus, American Midland Naturalist 33:128-206, Pennell, F,W, 1920, Penstemon, IN: Scrophulariaceae of the central Rocky Mountain states, Contributions U,S, Natl, Herbarium 20:325,381,