About Lupinus L.
This plant, a member of the Lupinus genus, is a perennial herb with thick, sturdy stems that reach up to 1.5 metres (4.9 ft) in height. Its leaves are palmately compound, with 9 to 17 leaflets each measuring 3 to 15 centimetres (1.2–5.9 in) long. Flowers grow on a tall spike; individual flowers are 1 to 1.5 centimetres (0.39–0.59 in) long, and wild plants most commonly have blue to purple blooms. Bumblebees are the main pollinators that visit these flowers. In particular, the L. polyphyllus variety contributes to a large number of hybrids that are commonly grown as garden lupines, which can have a very wide range of flower colors. Most lupines do not grow well in rich, heavy soils, and often only survive for a few years when planted in these conditions. This is because crown contact with manure or high levels of rich organic matter encourages crown rot. In ecological terms, this lupine can pose a major threat to the survival of the endangered Karner blue butterfly. The threat occurs because it hybridizes easily with Lupinus perennis, the wild perennial lupine, which is the Karner blue butterfly's food plant. Some sources note that commercial lupine seeds are already a risk to Karner blue butterfly conservation due to this hybridization. Additionally, humans continue to introduce incompatible lupine species into areas where the Karner blue butterfly currently lives or historically occurred. Lupinus is commonly cultivated in gardens because it attracts bees, produces attractive flowers, and can improve poor sandy soils through its nitrogen-fixing ability. Many cultivars have been selected for varied flower colors, including red, pink, white, blue, and multicolored blooms with different colored petals. Hybrids between L. polyphyllus and L. arboreus are commonly used, and are sold under hybrid group and cultivar names such as Rainbow Lupins, Lupin Tutti Fruitti, the mixed Band of Nobles, yellow Chandelier, red My Castle, white Noble Maiden, pink The Chatelaine, and blue The Governor. These plants are very hardy, able to survive extreme temperatures and tolerate frost down to at least −25 °C (−13 °F). Wild varieties can easily become invasive and are difficult to remove if not regularly managed. Growing lupins in containers can prevent them from spreading invasively into the ground. Lupins require a moderate amount of sun to grow, and perform best in light soils; they suffer when grown in heavy or clay soils. Once fully established, they are extremely resilient and can be divided through propagation. Seeds collected from a parent lupine plant will never grow into an exact genetic copy of the original, even when the resulting flowers have similar coloration. Low-alkaloid (sweet) cultivars of this lupine, suitable for use as a fodder crop, have been developed through breeding. A new breeding approach based on specific crossing has been created to prevent the restoration of alkaloid synthesis in cross-pollinated lupine species. Only compatible forms with low alkaloid content controlled by the same genetic system are used for hybridization. This approach has allowed transforming the original bitter, weedy plant into a valuable fodder crop. In growing conditions in Northwest Russia, the sweet commercial cultivar "Pervenec" – the first sweet lupine variety – has produced positive results, and it is included in the State Catalogue of selection achievements of Russia. Sweet lupine breeding programs are also conducted in Finland. Modern newer garden hybrids are highly poisonous, as they contain high levels of toxic alkaloids, and should never be eaten by humans. This species is also toxic to livestock.
