Wild Lupine is a native erect perennial growing from 8 to 24 inches high on stems that are light green to reddish green and have thin grayish-white hair. Branching, if any, is tightly compact and usually on older plants.
Leaves are alternate on long stems and are palmately divided into 7 to 11 oblanceolate leaflets and occur below the inflorescence. (Bigleaf Lupine has 11 to 17). Each leaflet has a smooth margin with fine hair and the midrib extends just beyond the tip forming a bristly tip. The upper surface is green and smooth while the lower is paler due to fine grayish-white hair. Leaflets are sessile but can rotate to track the sun. The leaf stalk is up to 4 inches long, green to reddish-green and hairy
The inflorescence is a tall raceme rising above the leaves bearing numerous flowers that can vary in color from blue (the normal) to pinkish to white. Like the stem, the raceme can be green to reddish-green.
Flowers: The flower calyx is light green to reddish in color with two large lobes. The corolla has 5 petals. Flower petals follow the pea structure with a large upper petal called a banner (or standard) and two lateral petals that come forward to enclose 2 smaller petals forming what is called the keel, which houses the reproductive parts of stamens and style. The banner turns backward at the sides. As the flower ages the banner becomes white in the center. Young flowers have a floral bract at the base that disappears with age.
Fruit: Flowers mature into oblong, flattened hairy pods that have 2 or more seeds (usually up to 7). These are dispersed from the pod which splits along two lines into spiral coils that eject the seeds.
Habitat: Wild Lupine is a long-lived nitrogen fixing plant that grows from a taproot which penetrates the soil to a great depth. It propagated by offsetting rhizomes from the root and by seed. It is a cool season plant so it dies down in the heat of summer and some years may not put up a stem. A short period of cold stratification and scarification is necessary for seed germination. The plant prefers well-drained sandy soils, slightly acidic, in full sun, partial shade tolerated.
Names: The genus name, Lupinus, means 'wolf' from the old belief that the plant robbed the soil of nutrients, when in fact the opposite is true. The species, perennis, means 'perennial' which separates this species from other Lupines which are annual or biennial. The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. The alternate common name of Sundial refers to the leaflet's ability to rotate up to 90 degrees to face the sun.
Above: The inflorescence is a tall raceme rising above all the leaves.
Below: 1st photo - Note the upper petal forms a banner and two lateral petals come forward completely enclosing the last two petals which form a 'keel'. Stem and flower stalk have grayish-white hair. 2nd photo - Each divided leaf has 7 to 11 leaflets with fine hair on the margins and a bristly tip formed by the midrib extending just beyond the tip.
Below: Leaves are all below the flowering spike. Seed pods are flattened, hairy, with 2 or more seeds. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: An historical photo of Lupine in the newly created Upland Garden. Photo from a Kodachrome taken by Martha Crone on May 31, 1946.
Notes: Wild Lupine is not indigenous to the Garden. Eloise Butler first introduced the plant on May 3, 1914 with plants from Gillett's Nursery in Southwick, MA. She planted others in 1921, '25, and '27. Martha Crone noted it in bloom in 1939 and planted seeds in 1945, '46, and '47, and it was present at the time of her 1951 Garden census. The 1940s plantings were when the Upland Garden was developed following its addition to the Garden acreage in 1944. It is also on the 1986 Garden census and present when these photos were taken in 2012. Wild Lupine is found in North America in the eastern half of the northern U.S. from Minnesota and Iowa eastward to the coast, excepting Missouri, Arkansas and Tennessee. It is not native to Canada but has been introduced. In Minnesota it has been found in a small strip of counties running from Cass and Crow Wing in the north diagonally southeastward to Fillmore and Houston. This includes only Hennepin, Ramsey, Anoka and Washington in the metro area. A close relative, Bigleaf lupine, Lupinus polyphyllus Lindl., is found only outside of that area in 4 NE counties.
Toxic: All wild lupines have toxic properties, primarily due to the lupin alkaloids in the foliage and seeds.
The Wild Lupine in Wisconsin is the larval host plant of the endangered Karner blue butterfly. Years ago Aldo Leopold wrote in Sketches Here and There: "Sometimes in June, when I see unearned dividends of dew hung on every lupine, I have doubts about the real poverty of the sands. On solvent farmlands lupines do not even grow, much less collect a daily rainbow of jewels. If they did, the weed-control officer, who seldom sees a dewy dawn, would doubtless insist that they be cut. Do economists know about lupines?"
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"