This is Eutrochium maculatum Gateway, also known as Joe Pye Weed. It is misleading to call this plant a weed with all of its many uses. Because of its astounding versatility this plant is considered an ornamental, an herb, a wildflower, a cut flower, and a butterfly plant. This plant will stay in bloom long after your other butterfly plants have finished. It is worth having this plant in your butterfly garden for many reasons but probably the biggest reason is that it will provide the butterflies a nectar plant when everything else is dormant. Documented butterflies who have gathered nectar from joe pye weed are the Great Spangled Fritillary, Viceroy, Painted Lady, Eastern Tiger Swallowtail, Little Glassywing, Summer Azure, and Silver-spotted Skipper. USDA Hardiness Zones 4 to 8.