Dogfennel

Dogfennel, Hogweed

Eupatorium capillifolium (Lam.) Small

Asteraceae (Sunflower Family)

▲ young plants

▲ ▼ young, mature plants (before flowering)

▲ older, mature plant

▲ ▼ stems and leaves

▲ leaf

Eupatorium capillifolium (Lam.) Small, Dogfennel, Tall Fennel, Sneezeweed: (Bayer Code: EUPCP; US Code EUCA5)

North American native herbaceous, simple perennial weed, with semi-woody, reddish-purple main stem that branches much in upper 2/3 of plant; can grow 2-6 feet tall; branches all angled strongly upright
Leaves are 2-3 times pinnately lobed into many thread-like segments and are closely spaced along the stem; leaves have a bad odor if crushed or bruised due to many glandular hairs on leaves
Flower head inflorescences are tiny (about 1/8 inch diameter), with green to white disk flowers (no ray flowers) and are born in large branched panicles at tips of stems
Bracts below inflorescences in multiple rows, green, oval with transparent margins and pointed at tip
Flowering is from late summer through mid-autumn
Can be toxic to horses and other gazing animals; may cause skin rash to animals or sensitive people that come in contact with it

Eupatorium:

Eupatorium is a genus of plants that includes weeds called Boneset, Dogfennel, Eupatorium, Joe-Pyeweed, Thoroughwort, (all of the white-flowered species are also called whitetop.
They are a group of perennial, native weeds that usually are not palatable to livestock, and some are poisonous
Besides the weedy species described, there are several ornamental native species/wildflowers that were previously included in this genus group (now placed in the genus, Eutrochium), that are found in moist soils and have large terminal clusters of white, pink or blue flowers; some have whorled leaves---Sweet JoePye Weed, Spotted JoePye Weed, Hollow-Stemmed JoePye Weed