Your editorial, “Lessons from Lupines” (June 25-26), made some good points but for me it ended with a clang when you expressed hope that Acadia National Park will find a way to coexist with lupine.

I have conducted research on some of the invasive plants in Acadia National Park as part of a large project, and I defend the staff in their effort to control bigleaf lupine (Lupinus polyphyllus) inside park boundaries. The lupine that fills our roadsides today is pretty when it flowers, but as you pointed out in the editorial, it is not native to Maine. I have observed lupine to spread like any recognized invasive plant, and have seen it displace both rare and common Maine plants. Lupine could have an impact on the migratory monarch butterfly because it crowds out native milkweed. The larva of the monarch depends on milkweed as its host plant; it cannot eat lupine.

Mind you, I endorse the freedom to grow lupine in the garden, or to spread the seeds on one’s own property and so “make the world more beautiful” as Barbara Cooney’s 1982 book about Miss Rumphius advocated. Not only are lupines colorful in flower, they hold soil in disturbed areas and provide pollen for bees. Lupines fix atmospheric nitrogen in root nodules, and improve soil fertility. In Washington, a lupine related to the species we see in Maine was a major colonizer in volcanic ash after the eruption of Mount St. Helens. Bigleaf lupine in its native range – the Pacific Northwest – is an integral part of some western ecosystems. But we should not assume that bigleaf lupine in Maine is harmless.

My issue is with the deliberate spreading of bigleaf lupine seeds on someone else’s property or on publicly owned land. This is a property rights matter, perhaps even a trespass. Much is at stake. In Australia, New Zealand, Finland and Iceland, bigleaf lupine has become as invasive as purple loosestrife is in our region. Because lupine makes rapid growth early in spring, lupine plants quickly fill up an area and exclude other plants, especially plants that emerge relatively late such as native milkweed.

If the patch of lupine is well-established, then few other plants grow among it. Lupine is reportedly toxic to horses, sheep, and other farm animals, so if it spreads into a pasture, it decreases the value of the hay and could make some animals sick or even kill them. Because lupine alters soils, it could make a habitat too fertile to support native reindeer lichen, poverty grass and other plants that would typically be in a disturbed open site.

I have watched over the past 25 years as town-owned blueberry fields on the southeast slope of Blue Hill Mountain became covered with bigleaf lupine. Not wind, not birds, but people purposely spread lupine seeds along the trail and in the blueberry fields – playing Rumphius, perhaps. In any event, today a large patch of purple and blue delights the eye of the regular hikers and other visitors. But there are costs to this short-sighted activity.

Where years ago there was a large patch of milkweed, now I can find nothing but bigleaf lupine. If milkweed has been displaced by lupine elsewhere, too, then the native monarch butterfly would appear to have less of its host plant available here at the northern end of its incredible 2,000-mile migration. In Mexico people have been cutting the trees near the stands in which the monarch butterflies spend the winter months, exposing the butterflies to winter winds. So this amazing insect appears to be pinched at both ends of its migration. We can help by promoting native milkweed instead of nonnative lupine.

And that’s not all. In 1990 on Blue Hill Mountain I found a small population of Orono sedge, a grass-like plant that grows only in Maine and nowhere else in the world. In 1998, there was no lupine in that part of the mountain. This year lupine is abundant in the section of field where the rare sedge grows, spread perhaps by some Rumphius wannabees. Unless something is done to control the lupine there, the sedge will disappear from the one natural population we know about in Hancock County.

I hope people will continue to enjoy bigleaf lupine, grow it in their gardens if they like, celebrate the Lupine Festival, photograph and paint the flowers, send lupine postcards to people who wish they were in Maine, pay a small fortune for a few lupine seeds in a gift shop. But please, neighbor, don’t spread lupine seeds on property that does not belong to you.

Instead, why not team up with the people who want to keep monarch butterflies from becoming extinct? Be part of the effort to keep patches of native milkweed in the fields and roadsides of Maine by planting milkweed on your land, and by mowing once a year (perhaps mid-May before milkweed emerges) to keep the shrubs and trees from taking over.

The management at Acadia National Park is doing the right thing. They are fulfilling their mission by controlling lupine in the park, and they are doing it at the best possible time – while the lupine population is still small. Let people admire lupine outside park boundaries. The park has the long-term health of the ecosystem and a rich array of native plant and animal species as their natural resource priority, and the staff has my full support.

Alison C. Dibble is a plant conservation biologist. She holds a Ph.D. in Plant Science from the University of Maine, where she is on the adjunct faculty. She is a Cooperating Research Ecologist with the USDA Forest Service, Northeastern Research Station, and is principal of Stewards LLC, a biological consulting firm, in Brooklin.