Eutrochium maculatum var. maculatum

Native

Wet to moist. Meadows, marshes, lakeshores. Full sun or partial shade.

July to September

Pale purple to pink

24″ to 80″

This is a 24″ to 80″ tall, erect, perennial forb that rises from a fibrous roots and sometimes rhizomes.

The stems are erect and usually light green with purple spots but are sometimes more evenly purple. They are usually solid but are sometimes hollow near the base. They are usually not covered with a whitish, waxy coating (glaucous). They are hairless except for a covering of minute, short hairs near the top.

Most of the leaves are usually in whorls of 4 or 5, sometimes in whorls of 3 or 6. They do not have a tight bundle of small leaves in the leaf axils. They are on hairless, 1 ⁄16″ to 1″ long leaf stalks. The leaf blades are relatively thin, lance-shaped to elliptic or egg-shaped, 3″ to 10″ long, and 1″ to 3½″ wide. They are tapered to a sharp point at the tip and tapered gradually to the leaf stalk at the base. There is a single main vein. The upper surface is dull and hairless. The lower surface is paler green and usually hairless. The margins are toothed with sharp, forward-pointing teeth. The uppermost whorl of leaves, the whorl directly subtending the inflorescence, is not broader than the inflorescence. The leaf blades of this whorl are ⅝″ to 1″ long and 1 ⁄16″ to 3 ⁄16″ wide.

The inflorescence is a branched, elongated, flat-topped or nearly flat-topped array of numerous flower heads at the top of the stem.

Each flower head has 8 to 22, usually 10 to 16, pale purple to pink disk florets and no ray florets.

The fruit is a ⅛″ to 3 ⁄16″ long achene with a fluffy tuft of hairs attached.

Holzinger’s eupatorium (Eupatorium purpureum var. holzingeri) stems are mostly green, purple only at the leaf nodes, and are rarely hollow near the base. The leaf undersurface is densely hairy. The inflorescence is dome-shaped, not flat-topped. The flower heads have 4 to 7 disk florets per head.

Spotted Joe Pye weed (Eutrochium maculatum var. bruneri) stems are densely covered from the base to the inflorescence with minute, short hairs. The leaves are relatively thick. The leaf undersurface is densely hairy.

Spotted Joe Pye weed (Eutrochium maculatum var. foliosum) uppermost whorl of leaves is much larger, as broad or broader than the inflorescence. The leaf blades of this whorl are 3″ to 8″ long and ¾″ to 1½″ wide. It has been reported only in Cook County.

Sweet Joe Pye weed (Eupatorium purpureum var. purpureum) stems are mostly green, purple only at the leaf nodes, and are rarely hollow near the base. The inflorescence is dome-shaped, not flat-topped. The flower heads have 4 to 7 disk florets per head. The flowers are pale pink to purplish.