Plant Wild Lupine (Lupinus perennis) for Karner Blue, Frosted Elfins, and Duskywings
Wild Lupine (Lupinus perennis), aka Sundial Lupine, is a valuable member of the pea family (Fabaceae). As with many legumes, it is a beneficial plant that helps replace nitrogen in the soil. The Frosted Elfin butterfly (Callophrys irus) and two Duskywings–Eastern Persius (Erynnis persius) and Wild Indigo (Erynnis baptisiae)–also rely on Wild Lupines. But did you know that by planting these beautiful and beneficial plants, you could help save an endangered species?
Help Save The Endangered Karner Blue
Wild Lupine is the only larval host plant used by the federally endangered Karner Blue butterfly (Lycaeides melissa samuelis); its caterpillars will eat nothing else.
The Karner Blue is now found in parts of WI, MI, NJ, NH, and NY. Local conservation efforts, focused on replanting large areas of lupine, are having modest success at encouraging the butterfly’s repopulation. You can help keep these butterflies from becoming extinct by planting these gorgeous flowers in your yard or field. You’ll enjoy the colorful blooms from spring through summer while the caterpillars feast on the leaves!
Characteristics Of Wild Lupine
This herbaceous perennial is native to the Eastern half of the United States but can be found in other parts of the country and lower Canada. It grows well in USDA zones 3-8, preferring cooler evening temperatures. Known mostly for the blue or purplish flowers, lupines may also bloom in pink to white shades. The spiky flowers appear on erect stems that reach up to 2′ tall.
Wild lupines are adaptable, but require well-drained soil above all else. They do well in acidic, loamy soil that is on the drier side. Their natural settings include large clearings, dry woods or the sides of sandy hills. In the northern part of the country, locations in full sun are preferred. The plants will still grow in hotter climates, but partial shade will be necessary.
The pretty flowers and interesting seed pods resemble those of their dainty cousin, the sweet peas. The flowers can reach up to 1” in length while the seed pods double that to 2”. Hairy seed pods house anywhere from 2-7 seeds, or even more. When fully mature, the pods explode and eject the seeds. This helps the Wild Lupine reseed and expand its territory.
Though it produces more pollen than nectar, Lupinus perennis is still a favorite of adult butterflies, hummingbirds, bumblebees and other long-tongued pollinators. You will be inviting a variety of winged visitors to your garden when you plant Wild Lupine seeds.
How To Start Wild Lupine Seeds
Lupinus perennis seeds are easy to get started. You can plant them directly in the fall and allow nature to provide the required chill for germination, or you can wait for spring.
For spring sowing, scarification (or ‘roughing up’ the seed coating) is recommended for dried seeds, followed by 10 days of moist stratification. Fresh or winter-sown seeds don’t require the scarification, but it can help speed up the germination process. We have high germination from our current seed with no scarification or stratification.
Lupine seeds should be planted about 1/4″ deep. Treating the soil with a rhizobium inoculant is suggested for fixing the soil. Depending on the temperature, sprouting can begin as early as 1-2 weeks. The area should be kept moist until the plants are established. Final spacing should be about 10-18″ apart.
Due to the long taproot that develops, lupines don’t respond well to being moved. You can, however, take rhizome cuttings from established plants in late summer or early fall. Transplant them right away, so they can develop roots before winter arrives.