Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Order: Scrophulariales

Family: Scrophulariaceae -- figwort

Common Name: hot rock penstemon, lava penstemon, scorched penstemon, scabland penstemon. Penstemons are also know as beard-tongues.

Species Code: PEDE4

Origin: Native to dry, open, often rocky places east of the Cascade Mountains from British Columbia to California and east to Montana and Wyoming.

Rare: no

Form: forb, perennial; 20-60 cm tall, much branched from the woody base; stems simple, decumbent at the base, glandular in the inflorescence, otherwise glabrous to finely puberulent.

Mature height: 8-24 inches

Duration: perennial

Longevity: medium life-span

Habitat Type: prairie

Wetland Indicator Status: not listed

Leaves: opposite or whorled, bright green, linear-lanceolate to elliptic, usually sharply toothed but sometimes entire; basal leaves short-petiolate, 1.5-5 cm long; cauline leaves sessile and reduced upward.

Flowers: numerous; inflorescence of several or numerous remote to crowded verticillasters; calyx 2.5- 6 mm long, lobes lanceolate to narrowly ovate, sometimes scarious margined; corolla tubular, white or very pale yellow, 8-20 mm long; pollen sacs glabrous, dehiscent throughout, becoming divaricate to explanate, staminode glabrous or bearded, not expanded at the tip, extending to the mouth of the throat.

Flower color: white

Bloom: May, June

Bloom starts on: late May

Bloom ends on: late June

Fruit: capsule, 4-5.5 mm long; seeds 1-1.5 mm long, pitted, brown.

Characteristics:
Reproduces sexually by seed.
2,765,854 seeds/lb (USDA NRCS Pullman PMC 2005).
n=8, 16 (Hitchcock et al 1969).
2n=16 (Baldwin et al 2004).
Flowers are perfect.
Fruit is a capsule.
Most Penstemons are not grazed by wildlife or livestock and have only minor medicinal uses (Strickler 1997).
Penstemon spp. are hosts for the larva of the Chalcedon checkerspot (Euphydryas chalcedona) butterfly (Pocewicz 2005).
P. deustus is pollinated mostly by small bees belonging to the genus Osmia. Bumblebees (Bombus spp.) are less common pollinators (Kramer et al 2011).
Flowers are protandrous and mostly outcrossed but some autogamy occurs (Kramer et al 2011).

Comments: The base of the plant tends to be somewhat woody.

Sun requirement: full sun

Soil moisture: xeric

Precipitation: 10-18 (USDA NRCS PLANTS Database 2009).

Fire: Rocky habitat probably protects the plants from fire.

Sowing time: fall

Transplant time: spring

Stratification: cold moist

Seed yield: high

Seed harvest: easy

Seed first harvest: second season

Seed cleaning: easy

Planting duration: moderate

Seed insect problem: none noted

Seed shatter: medium

Seed size: small

Seed harvest date: August

Seed comments: Plants hold the seed well.

Herbaria: Specimen data and digital resources from The Consortium of Pacific Northwest Herbaria

Keywords: native perennial upland forb

Propagation:
2 protocols in the Native Plant Network
Pullman PMC
Rocky Mountain Research Station, Boise, ID

Other Propagation Information:
Seed of some Penstemon spp. loses dormancy after 2.5 years of storage (Allen & Meyer 1990).
Seeds germinate without pretreatment (Mirov & Kraebel 1939).
Reproduces sexually by seed.

Notes: Penstemon deustus has pure white flowers and serrated leaf margins which differentiate it from the other local species. It prefers rocky sites, but can be grown on deep soils where it does not have competition from other plants. The stalks do tend to droop over, so it might need support. Flowers in mid June (Skinner et al 2005).

References:
Allen, Phil S., and Susan E. Meyer. 1990. Temperature Requirements for Seed Germination of Three Penstemon Species. HortScience 25(2):191-193.

Baldwin, B.G., S. Boyd, B.J. Ertter, D.J. Keil, R.W. Patterson, T.J. Rosatti, and D.H. Wilken (eds). 2004. Jepson Online Interchange for California Floristics. University and Jepson Herbaria, University of California, Berkeley, CA. Accessed 12/8/09 online at http://ucjeps.berkeley.edu/interchange.html

Castellanos, M., P. Wilson, and J. Thomson. 2003. Pollen Transfer by Hummingbirds and Bumblebees, and the Divergence of Pollination Modes in Penstemon. Evolution 57:2742-2752.

Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press. Seattle, WA. 5 vol.

Kitchen, Stanley G., and Susan E. Meyer. 1992. Temperature-Mediated Changes in Seed Dormancy and Light Requirement for Penstemon palmeri (Scrophulariaceae). Great Basin Naturalist 52:53-58.

Kramer, Andrea T., Jeremie B. Fant, and Mary V. Ashley. Influences of Landscape and Pollinators on Population Genetic Structure: Examples from Three Penstemon (Plantaginaceae) Species in the Great Basin. American Journal of Botany 98:109-121.

Meyer, Susan E. 1992. Habitat Correlated Variation in Firecracker Penstemon (Penstemon eatonii Gray: Scrophulariaceae) Seed Germination Response. Bulletin of the Torrey Botanical Club 119:268-279.

Meyer, Susan E., and Stanley G. Kitchen. 1992. Cyclic Seed Dormancy in the Short-lived perennial Penstemon palmeri. Journal of Ecology 80: 115-122.

Meyer, Susan E., and Stanley G. Kitchen. 1994. Habitat-Correlated Variation in Seed Germination Response to Chilling in Penstemon Section Glabri (Scrophulariaceae). American Midland Naturalist 132:349-365.

Mirov, N.T., and C.J. Kraebel. 1939. Collecting and Handling Seeds of Wild Plants. Civilian Conservation Corps Forestry Publ. No.5. US Government Printing Office. Washington, DC.

Pocewicz, Amy. 2005. Host Plants of Palouse Butterfly Species. 2 page handout to accompany the April 2005 presentation to the Palouse Prairie Foundation.

Skinner, David M., Paul Warnick, Bill French, and Mary Fauci. 2005. Characteristics and Uses of Native Palouse Forbs in Landscaping. USDA NRCS Pullman Plant Materials Center and Palouse Prairie Foundation. Online at http://www.wsu.edu/pmc_nrcs/Docs/Forbs_for_Landscaping.pdf

Strickler, Dee. 1997. Northwest Penstemons. The Flower Press. Columbia Falls, MT.

USDA NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 8 December 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

USDA NRCS, Pullman Plant Materials Center. 2005. Seed Weights of Some Palouse Native Species. Pullman Plant Materials Center, Pullman, Washington. Online at http://www.wsu.edu/~pmc_nrcs/Docs/Seed_Weights_Palouse_Native_Species.pdf

Links: Plant Profile from the USDA PLANTS Database
Species information from the University of Washington Herbarium