Sundial Lupine, Lupinus perennis

2024 May Plant of the Month

Northern Neck Chapter of the Virginia Native Plant Society

By Betsy Washington

*Sundial Lupine’s showy flowers and foliage (by Kevin Howe)*

Every spring I look forward to seeing the lovely lavender-blue spires of Sundial Lupine rising above distinctive pinwheel foliage along sandy roadsides and open woods. Also known as Wild Lupine, this member of the Legume Family is found throughout the Eastern and Central United States. In Virginia they are infrequent to locally common in the Coastal Plain and north-central mountains but rarely found in the Piedmont and the SW mountains. Lucky for us, they prefer dry sandy open forests, clearings, pine barrens, and roadsides and are always a joy to happen upon in April and May when in bloom. Sundial Lupine colonies can be spectacular where they thrive in sandy, nutrient-poor, acidic soils. The Latin scientific name Lupinus refers to a ‘wolf” because it was once thought that lupines “stole or wolfed” nutrients from the poor soils where they grow, Not so, like all other legumes, Lupines contain nitrogen-fixing bacteria in nodules on their roots that produce nitrogen and actually enhance soil fertility.

The common name, Sundial Lupine, refers to the fact that the flowers tend to orient themselves to face the sun through the day. Multiple 4 -10” tall racemes of spectacular blue-violet pea-like flowers rise above the foliage in April and May, delighting humans and an array of pollinators including bees, butterflies, and hummingbirds while they track the sun. The soft gray-green foliage is also quite distinctive with palmately-compound leaves, each with 7 – 11 lance-shaped leaflets radiating from a central point and held on a long hairy stalk. Plants spread by rhizomes into large showy colonies, creating a spectacular, long-lasting spring display. They are followed by 2” long hairy pods which forcefully expel their black seeds several yards from the parent plant in early summer. Plants die back soon after flowering and are often short-lived, but readily perpetuate themselves by self-seeding or by their rhizomes.

Sundial Lupines sometimes have a reputation for being tricky to grow in gardens; they do not tolerate rich soils nor competition from other plants. Plant them in well-drained, acidic sandy to sandy-loam or even gritty soils in part shade to full sun. Plants spread by seed and rhizomes and are easily propagated from seeds or by root cuttings. The hard seed coat is best scarified (make shallow cuts in seed coat) before planting to simulate the freezing and thawing in nature that breaks down that hard coat. Lupines are best used in naturalistic gardens, meadows, coastal or butterfly gardens or to light up the edges of sandy, open woods where they will not leave a noticeable gap when the foliage dies back in mid-summer.

Sundial Lupine is an important wildlife plant, providing seeds for birds and small mammals as well as nectar for a variety of pollinators. It is also the sole host plant for the caterpillars of the Karner Blue Butterfly, which is endangered and found to our north. Lupine (and the Karner Blue Butterfly) were once much more common prior to fire control and as Wild Lupine populations have declined, the Karner Butterflies populations have plummeted to near extinction. Compounding the problem, Western species of Lupine have been introduced into the East where they have spread through New England, hybridizing with our native Sundial Lupine. These hybrids are now widespread and are apparently unpalatable to the Karner Blue larvae further threatening their survival. Sundial Lupine is also the host for the lovely Frosted Elfin Butterfly. This butterfly is a Virginia Species of Special Concern because it is quite rare and, in fact, was thought to be extinct in Virginia in 1994 until 2011 when populations were found in the city of Suffolk and Antioch Pines Natural Area Preserve in Isle of Wright County. There is considerable interest in re-establishing colonies of lupine for their ecological importance.

The seeds of Sundial Lupine are poisonous and can cause loss of muscular control and difficulty moving or breathing or even death, however they were used by Native Americans to make a tea to treat nausea. Skip the tea and enjoy the beauty and the wildlife supported by this beautiful wildflower and take advantage of its preference for sandy, barren soils to create beautiful colonies in a naturalistic garden. You will create a stunning spring show while providing critical wildlife habitat. It doesn’t get much better!

Plant of the Month May 2024: Sundial Lupine