Lupine plants belong to the family of Legumes which have the unique ability of fixing nitrogen into the soil. Over 300 varieties of lupine exist. The plants produce flowers in the early summer that stand 1 to 4 feet in height. The raceme flower spikes appear in shades of blue, purple, white, yellow and pink. A relatively short-lived perennial, the lupine grows wild throughout most of the United States. Widely cultivated as an ornamental garden plant, it easily self-seeds and spreads.
In ancient Egypt and Mediterranean regions, the cultivation of lupine began 2,000 years ago, according to horticulturists at the University of Purdue. Germany produced the first alkaloid-free cultivars of the plant, which enabled the high protein seeds to be consumed by both humans and livestock in the 1920s. The plants quickly became a popular forage crop throughout Poland, Australia, Germany, the Mediterranean and parts of Russia.
Alkaloid-containing lupine varieties are toxic if consumed by animals or humans. The stems, leaves and flowers of the plant contain quinolizidine alkaloid. Sheep appear to be at serious risk for toxicity from lupine plants, according to researchers at the University of Pennsylvania.
Lupine plants grow best in moist soil conditions with high organic material. Despite its affinity for moist soil, the lupine has the ability to withstand drought once established, due to its exceptionally long taproot. The lupine will not tolerate clay soil and easily dies when within it. The plant prefers full sunlight but will tolerate moderate shade.
Lupine can be propagated from division, cuttings and seeds. Seeds require a period of cold stratification for germination to occur. Normally, only seven days in a refrigerator is required prior to planting. The lupine does not transplant well due to its exceptionally long taproot.
In numerous locations, the lupine is considered endangered in its wild habitat. Unfortunately, in the state of Ohio the larvae of the karner blue butterfly lived on the wild lupine. When the lupine disappeared in the wild, the butterfly disappeared also but, thanks to replanting, the lupine is growing and the butterfly has returned, according to Ohio Northwest Nature.