Bigleaf lupine are beautiful but non-native. There is a native alternative. Nature News

Lupines are one of those iconic wildflowers that we all love to see blooming along roadsides in early summer.  My idealiz

ed lupine bubble burst recently when I discovered that those lupines are most likely bigleaf lupine (Lupinus polyphyllus), a non-native plant that was introduced to Maine and New Hampshire as a landscaping plant from its native western United States.  It is considered an invasive species here because it has the ability to crowd out native species.  For example it can displace milkweed, a plant necessary to monarch butterflies whose caterpillars can’t eat lupines − only milkweed. Bigleaf lupine can also be an issue for grazing animals (both farm animals and native herbivores) because the seeds can be toxic if consumed in quantity.

Who can forget Barbara Cooney’s delightful picture book "Miss Rumphius," who, in her quest to make the world a more beautiful place, plants lupines throughout the countryside of Maine. This story is based upon a real person, Hilda Hamlin.

Hamlin emigrated from England to coastal Maine in the early 1900s and planted bigleaf lupine in her garden.  According to “The Literary Gardener” (by Carol Howard) Hilda Hamlin at first “imported her lupine seeds from her native England. As the plant is native to North America, she likely purchased the seeds bred by George Russell, a British horticulturist whose tireless cultivation of Lupinus polyphyllus over the first half of the 20th century gave him international fame and made his lupines a sought-after plant. Hamlin probably started out with later versions of Russell’s original hybrids — sensational plants with densely packed clusters of red, yellow and orange blossoms. As she preserved seeds from the mature plants and scattered them throughout the countryside, the showy hybrids must eventually have reverted to the loosely clustered flowers of subtle blues and purples that have naturalized along the Atlantic coast.”

But Hamlin wasn’t the only one spreading lupines about. As mentioned previously it had already been introduced from its native Northwest, often planted for its nitrogen-fixing ability. Lupine’s roots, like other members of the pea family, form a symbiotic relationship with nitrogen-fixing bacteria, enriching the soil around them with this much-needed nutrient. Its deep tap root helps prevent erosion, another reason besides its beauty to plant it along roadsides. Hummingbirds and many bees also love it.

Should we be pulling up bigleaf lupine? The National Park Service, which prioritizes protecting native species and works to eliminate non-native invasive species, typically removes bigleaf lupine when it encroaches upon natural habitat.  However when attempts were made to eradicate it from Acadia National Park, where it is a famous crowd pleaser, visitors protested so vehemently that the effort to completely remove it was halted.

Lupine lovers do have an option. Sundial lupine (Lupinus perennis) is a lupine native to the Northeast, so named because its leaves follow the sun.  Sundial lupine is most likely gone from most of Maine due to habitat loss, plant collecting, and development, as well as hybridization with bigleaf lupine. It is smaller and less showy than bigleaf lupine but provides the same ecosystem services like nitrogen-fixation and erosion control and is just as attractive to pollinators.  In particular it is the only host plant for the endangered Karner blue butterfly (these are probably extinct in Maine).

We planted a couple bigleaf lupines a few years ago before thinking about converting to primarily native species in our gardens.  They aren’t growing very aggressively and so we are letting them remain alongside the native milkweed (that is aggressively taking over parts of the yard-yay!) but are also planting sundial lupines everywhere we can in the hopes that one day tiny Karner blue butterflies will come to our lupines in the same way monarch butterflies return every summer to our milkweed.

Susan Pike, a researcher and an environmental sciences and biology teacher at Dover High School, welcomes your ideas for future column topics. Send your photos and observations to spike3116@gmail.com. Read more of her Nature News columns online at Seacoastonline.com and pikes-hikes.com, and follow her on Instagram @pikeshikes.

This article originally appeared on Portsmouth Herald: Sundial lupine are a native alternative to bigleaf lupine: Nature News