Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Order: Fabales

Family: Fabaceae -- pea

Common Name: spurred lupine

Species Code: LULA3, LUAR6

Origin: Native to open places from sagebrush to open pine forests of southern British Columbia south to California and east to Utah and Montana.

Rare: no

Form: forb, perennial; stems numerous, erect to spreading, simple to sparingly branched, 20-50 cm tall, strigillose, greenish to grayish overall.

Mature height: 8-20 inches

Duration: perennial

Longevity: short

Habitat Type: prairie, forest

Wetland Indicator Status: not listed

Leaves: mostly cauline, alternate, long petiolate, palmately compound with 7-11 leaflets; leaflets oblanceolate to oblong-lanceolate, 2-6 cm long, pubescent on both sides or glabrous above.

Flowers: papilionaceous; perfect; borne in a raceme, whorled, scattered or crowded, 9-14 mm long; calyx 2 lipped with a conspicuous spur 1-3 mm long on the base of the upper lip; corolla variable from white to purple, 8-14 mm long, banner slightly reflexed, pubescent on the upper portion of the back, wings glabrous or pubescent at the tip, margins ciliate on upper keel, glabrous on lower keel.

Flower color: blue/purple

Bloom: May, June, July

Bloom starts on: late May

Bloom ends on: early July

Fruit: pods 2-3.5 cm long by 6-9 mm wide, silky, containing 3-6 seeds; seeds pinkish-brown, 5-6 mm long, discoid.

Characteristics:
Lupinus arbustus Dougl. ex Lindl. is the currently accepted name.
As a genus, Lupinus is highly variable and plastic. This is further complicated by interbreeding, resulting in a highly confusing taxonomy and a large number of infraspecific taxa.
L. arbustus in St. John 1963, L. laxiflorus in Piper & Beattie 1914, in Davis 1953, and in Hitchcock et al 1969.
Reproduces sexually by seed.
n=24, 48 (Hitchcock et al 1969).
Flowers are perfect.
Fruit is a legume.
Seeds are ejected explosively when the pods dehisce.
Lupines contain poisonous alkaloids in varying amounts depending on species, plant part, maturity, and possibly ecotype. Seeds and fruits have the highest concentrations.
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: mesic

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).

Hazards: contain poisonous alkaloids

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

Transplant time: spring

Pretreatment: seed should be scarified

Seed yield: no information available

Seed harvest: medium difficulty

Seed first harvest: Lupines often produce seed in the first year

Seed cleaning: easy

Planting duration: short

Seed insect problem: yes

Seed shatter: medium

Seed size: large

Seed harvest date: no information available

Seed comments: spurred lupine reportedly holds its seed better than other lupine species.

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

Key words: native perennial upland forb

Propagation:
Physical dormancy due to a hard seed coat is common in Fabaceae and scarification usually aids germination.
Reproduces sexually by seed.

Notes: Lupinus laxiflorus seed may hold in the pods longer than some of the other species of lupine. Haven’t grown this one, but see no reason it wouldn’t be a good landscape species. Other names include Lupinus arbustus, spurred lupine (Skinner et al 2005).

References:
Davis, Ray J. 1952. Flora of Idaho. Wm. C. Brown, Dubuque, Iowa. 827 pp.

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.

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. Lancaster, PA: Press of the New Era Printing Company. 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. More Palouse Forbs for Landscaping. USDA NRCS Pullman Plant Materials Center and Palouse Prairie Foundation. Online at http://www.wsu.edu/pmc_nrcs/Docs/More_Forbs_for_Landscaping.pdf

St. John, Harold. 1963. Flora of Southeastern Washington and of Adjacent Idaho. 3rd edition. Outdoor Pictures. Escondido, CA.

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