Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Family: Scrophulariaceae

Common Name: yellow penstemon

Species Code: PECO6

Origin: Native to open grasslands and open forests east of the Cascade Mountains from southern British Columbia to Oregon and east to western Montana.

Rare: no

Form: forb, perennial from a woody caudex, ascending to erect, 20-50 cm tall, glabrous throughout (the stem sometimes hirtellous-puberulent above), often with sterile mat-forming shoots at the base.

Duration: perennial

Longevity: medium

Habitat Type: prairie, forest

Wetland Indicator Status: not listed

Leaves: entire, bright green; lower ones petiolate, lanceolate to spatulate, 3-15 cm long, glabrous; cauline leaves opposite, entire, sessile to clasping, lanceolate, to 10 cm long, becoming much reduced in the inflorescence.

Mature height: 8-20 inches

Flowers: inflorescence of 2-10 compact verticillasters, the lower remote; bracts scarious margined, erose, often resembling the calyx segments; calyx 5-lobed, 2-5 mm long, lobes with scarious, erose margins; corolla tubular, cream to pale yellow, declined (curved downward), bilabiate, 4-12 mm long; palate bearded; staminode not extending outside the corolla, brownish bearded with an expanded tip; pollen sacs purple, glabrous, fully dehiscent and explanate.

Flower color: yellow

Bloom: May, June

Bloom starts on: May 31

Bloom ends on: June 28

Fruit: capsule, 4-5 mm long; seeds 0.5-1 mm long.

Characteristics:
Reproduces sexually by seed.
4,628,571 seeds/lb (USDA NRCS Pullman PMC 2005).
1,868,526-2,700,000 seeds/lb (Hassell et al 1996).
Perennating organ is a woody caudex.
n=16.
P. confertus is a tetraploid (Keck 1945).
Flowers are perfect.
Fruit is a capsule.
P. confertus is a minor constituent of fall diet of Rocky Mountain elk (Kufeld 1973). 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).
Hummingbirds and bees pollinate many Penstemon spp.

Comments: flowers are pale yellow, not true white

Sun requirement: full sun to partial shade

Soil moisture: mesic

Precipitation: 15-65 inches (USDA NRCS PLANTS Database 2009).

Sowing time: fall

Transplant time: spring

Stratification: 90+ days cold moist

Seed yield: medium

Seed harvest: moderately difficult

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 to early September

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

Propagation:
2 protocols in the Native Plant Network
Glacier Nat. Park, MT

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

Hassell, Wendell, W. Rocky Beavers, Steve Ouellette, and Thomas Mitchell. 1996. Seeding Rate Statistics for Native and Introduced Species. Denver, CO: US Dept of Interior and USDA, NRCS.

Kufeld, Roland. 1973. Foods Eaten by the Rocky Mountain Elk. Journal of Range Management 26:106-113.

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

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

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

USDA, NRCS. 2009. The PLANTS Database. Batpon Rouge LA: National Plant Data Center. http://plants.usda.gov, 13 July 2009.

Some references of interest for other species of Penstemon include:
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. (P. strictus, P. barbatus).

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.

Meyer, S.E., and S.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 (other Penstemon spp.).

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.

Nelson, David A. 2005. Evaluation of Penstemon as a Host for Castilleja in Garden or Landscape. Native Plants Journal 6(3):254-262. (P. strictus)

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