Lupine, Lupinus perennis

Lupine

Lupinus perennis

Benefits:
Sun Shade:
Bloom Time: Late Spring/Early Summer
Zones: 3, 4, 5
Soil Conditions: Sand
Soil Moisture: Dry
Color: Blue
Fragrance: No
Height: 1 - 2 feet
Spacing: 1 foot


Description

Lupines (Lupinus perennis) are 1-2½ feet tall and compactly branched. The stems are light green to reddish green, angular or terete, and canescent-hairy. Alternate compound leaves occur along the stems; individual leaves are palmate with 7-11 leaflets. Individual leaflets are 1-2½ inches long and oblanceolate in shape; their margins are smooth and ciliate. The upper surface of the leaflets is medium green and hairless, while the lower surface is pale green. Each compound leaf has a long ascending petiole about 1-4 inches long that is light green to reddish green. The stems, petioles, and leaf undersides are sparsely to moderately canescent-hairy. The upper stems terminate in narrow racemes of flowers about 4-10 inches long. The flowering stalks are light green to reddish purple. Individual flowers are about ¾ inch long, consisting of 5 blue-violet petals (rarely white or pink), a tubular calyx with large lobes, several stamens, and a pistil with a single style. The petals have a pea-like floral structure, consisting of a large upper banner and 2 wings that project forward to enclose the keel. The lateral edges of the banner fold backward from its center; as a flower ages, the center of the banner becomes more white. The calyx is light green to reddish purple. The slender pedicels of the flowers are up to ½ inch long. The flowering stalks, calyces, and pedicels are sparsely to moderately canescent-hairy. At the base of each flower, there is a linear-lanceolate floral bract that soon withers away.

The blooming period occurs from late spring to early summer and lasts about 1 month for a colony of plants. Afterwards, the flowers are replaced by elongated seedpods about 1¼-2" long and canescent-hairy. Each seedpod contains about 7 seeds, which can be ejected several feet away from the mother plant. The root system consists of a taproot with rhizomes. Reproduction is by seed and vegetative clones from the rhizomes.

Habitats include sand prairies, openings in sandy woodlands, sandy savannas, edges of sandy woodlands, stabilized sand dunes, and powerline clearances in sandy areas. Dominant canopy trees in some of these habitats are either oaks (especially Black Oak) or pines.

Grow in organically rich, moderately fertile, slightly acidic, evenly moist, well-drained soils in full sun. The root system can fix nitrogen into the soil. The seeds should be scarified to facilitate germination. Individual plants can be short-lived or long-lived, depending on environmental conditions. Plants appreciate some light afternoon shade in hot summer areas. Good air circulation helps combat powdery mildew.

Plant Notes and Herbal Uses
  Purchase potted plants in spring or start from seed.
  Treating roots with a legume inoculant improves plant performance.
  Apply mulch around plants to help keep root zones cool.
  Deadhead spent flower spikes to encourage additional bloom.
  The foliage is toxic to sheep and horses, however deer, rabbits, and woodchucks occasionally browse on Wild Lupine.
Further Information

Wild Ones of the Fox Valley Area
Prairie Nursery
Wisconsin DNR
Wisconsin Native Plant Nurseries