blue, or purple. Most lupine varieties sold today are hybrids of the wild lupine plant. A fast-growing legume in the pea family, this North American native is a nitrogen fixer that improves the soil.

The scarce butterfly can be found in grasslands and around host plants such as wild blue lupine and wild indigo. Their numbers continue to decline, and they are predicted to be federally endangered.

It started with the lupine.Last spring, I started taking the hound to Thompson’s Field, a 57-acre conservation area off Route ...