Sicklekeel lupine, or lupinus albicaulis as it is known botanically, is an annual flowering herb. Each year the plant produces tall flower stalks that bloom in hues of white, pink, lavender or purple-blue from June through August. Sicklekeel lupine is related to the pea family and readily naturalizes by shedding its seeds in the late summer or early fall. Its flowers are attractive to hummingbirds and butterflies, and it thrives in full sun to light partial shade exposures.
Harvest lupine flower stalks just as they reach their peak beauty for use in cut flower arrangements or for dried wildflower bouquets. Cut down the stalk to the base at the crown of the plant and pull the stem out. Dead head fading flower stalks throughout the growing season to encourage new blooms. Prune away any damaged or diseased foliage or stems as you find them and discard in the compost pile or trash.
Hard prune your sicklekeel lupine in the late fall or early winter after the seed heads have broken open and the first hard frost has come. Alternatively, prune back the plant when it begins to look scraggly and is dying back. If you do not wish to have the plant self sow, cut back all of the flower heads in the early summer as the blooms fade. Use secateurs or shears to cut down the stalks to an inch or so above the crown of the plant. The crown and roots will degrade and feed the soil on their own or the entire plant can be lifted out of the soil and discarded in its entirety.
Water your sicklekeel lupine after pruning to reduce stress on the plant, prevent shock and speed fresh healthy top growth. In warmer climates where sicklekeel lupine has a long, almost perennial, growth season, mulch around the base of the plants with shredded bark or cocoa hulls to hold moisture to the soil, keep down competitive weeds and maintain a tidy looking soil surface.