Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Order: Fabales

Family: Fabaceae -- pea

Subspecies: The Palouse phase is ssp. sericeus.

Common Name: silky lupine

Species Code: LUSE4

Origin: Native to open dry to moist places from sagebrush to open pine forests mostly east of the Cascade Mountains of British Columbia south to Oregon, Nevada, and Arizona and east to Colorado and Alberta.

Rare: no

Form: forb, perennial from a branching crown; stems 20-70 cm tall, mostly simple or sparingly branched, with silvery to rust colored pubescence.

Mature height: 8-28 inches

Duration: perennial

Longevity: short

Habitat Type: prairie, shrub thickets, forest

Wetland Indicator Status: not listed

Leaves: mostly cauline, alternate, lower leaves with long petioles, much shorter above, palmately compound with 5-9 leaflets; leaflets oblanceolate, 3-6 cm long, sericeous-silky on both surfaces.

Flowers: papilionaceous; perfect; racemes loose, open, whorled, 11-32 cm long; corollas 10-13 mm long, mostly blue or lavender but sometimes pink or white; calyx silky, sometimes saccate but not spurred, 2-lipped, the upper bidentate, the lower entire and somewhat longer than the upper; banner well reflexed, silky-hairy on at least 2/3 of the back; wings usually glabrous, keel ciliate on the upper edges.

Flower color: blue/purple, rarely pink or white

Bloom: May, June, July

Bloom starts on: late May

Bloom ends on: mid July

Fruit: pods densely silky, 2-3 cm long by about 1 cm wide, seeds 3-6, light pinkish-brown.

Characteristics:
Reproduces sexually by seed.
As a genus, Lupinus is highly variable and plastic. This is further complicated by interbreeding, resulting in a highly confusing taxonomy, a large number of infraspecific taxa, and a long list of synonyms.
L. ornatus in Piper & Beattie 1914.
Hitchcock et al (1969) recognized L. sericeus var. asotinensis, occurring mostly in Asotin County but extending north of the Snake River into Whitman County and differing from the species mostly in having white flowers and only slight pubescence on the back of the banner. More recently it has been accorded specific rank as L. garfieldensis C.P. Sm., occurring in Asotin, Garfield and southern Whitman County. The Washington Natural Heritage Program (2009) ranks it R1, meaning the status is under review until more data is obtained to permit another rank to be assigned.
12,900-42,000 seeds/lb (Hassell et al 1996).
24,550 seeds/lb (USDA NRCS Plants Database 2009).
n=24 (Hitchcock et al 1969).
Flowers are perfect.
Fruit is a legume.
Seeds are ejected explosively when the pods dehisce.
Perennating organ is a caudex.
Lupines contain poisonous alkaloids in varying amounts depending on species, plant part, maturity, and possibly ecotype. Seeds and fruits have the highest concentrations. Wildlife eat the plants, but they are toxic to domestic livestock, especially sheep.
L. sericeus is a valuable forage for Rocky Mountain elk in winter, spring, and summer (Kufeld 1973).
Lupinus species are hosts for the larva of the persius duskywing (Erynnis persius), the arrowhead blue (Glaucopsyche piasis), the acmon blue (Icaricia acmon), Boisduval's blue (Icaricia icarioides ssp. pembina), and the silvery blue (Glaucopsyche lygdamus) butterflies (Pocewicz 2005).

Sun requirement: full sun

Soil moisture: xeric to mesic

Precipitation: The USDA NRCS PLANTS Database (2009) lists the precipitation range as 5-11 inches. It is doubtful the species is that drought tolerant and it certainly occurs commonly in higher precipitation areas such as the Palouse.

Fire: Lupines resist fire by having deep taproots and the ability to form new shoots from the taproot. The new shoots will produce seed the year following a fire (McLean 1969).
Resprouts from the caudex and deep roots after a fire. Also grows from seed stored in the seed bank (Matthews 1993).

Hazards: may contain poisonous alkaloids

Sowing time: Unscarified seed should be fall sown. Scarified seed can be spring sown.

Transplant time: spring

Pretreatment: scarification aids germination

Seed yield: medium

Seed harvest: difficult

Seed first harvest: first season

Seed cleaning: easy

Planting duration: short

Seed insect problem: yes

Seed shatter: high

Seed size: large

Seed harvest date: mid July

Seed comments: flowering and seed maturity is indeterminate, seed shatters readily

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

Keywords: native upland perennial forb

Propagation:
2 protocols in the Native Plant Network
Pullman WA Plant Materials Center
Glacier National Park, Montana

Other Propagation Information:
Reproduces sexually by seed.

Notes: Lupinus sericeus grows readily from scarified seed. Individual plants are short-lived but it reseeds readily. Seeds shatter forcefully, so it will move around (Skinner et al 2005).

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

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.

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

Matthews, Robin F. 1993. Lupinus sericeus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2009, November 20].

McLean, Alastair. 1969. Fire Resistance of Forest Species as Influenced by Root Systems. Journal of Range Management 22:120-122.

Piper, C.V., and R.K. Beattie. 1914. The Flora of Southeastern Washington and Adjacent Idaho. Press of the New Era Printing Company, Lancaster, PA. 296 pp.

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

USDA NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 20 November 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Washington Natural Heritage Program. Washington State Department of Natural Resources. 2009. List of Plants Tracked by the Washington Natural Heritage Program. Online at http://www1.dnr.wa.gov/nhp/refdesk/lists/plantrnk.html Accessed 11/20/09.

Links:
Plant Profile from the USDA PLANTS Database
Species account from the Fire Effects Information System
Species information from the University of Washington Herbarium