Flower:

Loose branching rounded clusters made up of dozens to hundreds of very pale pink to purplish flower heads. A head is made up of about 6 petal-less disk flowers, each with 2 long stringy styles and 5 tiny lobes. The bracts are green to purplish and in 2 layers, the outer ones usually hairy.

Leaves and stems:

Leaves are whorled in groups of 3 to 5, most often 4. Leaves are up to 10 inches long, 1 to 4 inches wide, coarsely toothed and pointed on both ends with short stalks, and are variously hairy.

Stems are mostly green, rarely purple tinged, but usually dark purple at the leaf nodes and flower stalk nodes. The lower stem is hairless; the upper stem may be covered in glandular hairs.

Fruit:

The flower heads turn into a mass of brown seed, each with a tuft of light brown hair to carry them off in the wind.

Seeds are slender, 4 to 5 millimeters long, 5-sided.

Notes:

Very similar species is Spotted Joe Pye Weed (Eutrochium maculatum), which has solid purple or purple spotted stems, usually a flatter flower cluster and a preference for full sun, where Sweet Scented Joe Pye Weed prefers part shade. Sweet Scented Joe Pye Weed often goes by Latin name Eupatorium purpureum but the accepted name in Minnesota is Eutrochium purpureum. There are 2 varieties in Minnesota, var. purpureum is mostly hairless on the underside of the leaf except along the veins; var. holzingeri is densely hairy on the underside surface.