Scientific Name: Eupatorium capillifolium

Common Name: dogfennel

Other Common Names: dog-fennel thoroughwort

Habit: 20 in to 6 1/2 ft in height, with 1 to several stems from a thick woody base. Many small flower heads are created from the upper stem branches. Leaves are pinnately dissected into fine, linear segments. Stems are erect, starting from the woody base, much-branched in the upper flowering portion, hairy, or sometimes smooth below, reddish purple at the base. It has fibrous roots and a woody stem at the ground level that sometimes resembles a taproot. Upright flowering stems persevere through the winter and often into spring. In warmer climates, young plants may die back to the crown and resprout in the spring. Dogfennel characteristically shows itself in nurseries, orchards, crops with decreased tillage, and landscapes. It also grows in abandoned fields and roadsides.

Leaves: Seedling: Cotyledons are egg-shaped, petiolated, and hairless. Young leaves are opposite; the first and sometimes the second pair of leaves have 1-3 coarse teeth, but successive leaves are dissected. Blades are hairy. Mature Plant: Majority of the leaves are alternate; some lower leaves may be opposite. Leaves are once or twice pinnately dissected into fine linear segments.

Identifying Characteristics: When crushed, leaves and particularly flowers give off a strong foul odor.

Flower Seed Head: Flowers are generated in September and October. Flower heads are small and abundant, in much-branched panicles on the upper 1/3-1/4 of the upright stem. Individual heads are small, 2-3 mm long, with 3-6 greenish white disk flowers on each head.

Seed Fruit: Reproduces by seed. The seed is enfolded within the fruit (achene), which is smooth, gray to black, angled in cross section, widest at the apex and 1-1.6 mm long The pappus consists of whitish bristles.

Where Found: Found along the coastal plain from Massachusetts south, all through the Southeast to Texas; generally found anywhere from New Jersey southward

  • Life cycle: perennial

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Asteraceae

  • Leaf arrangement: alternate

  • Leaf shape: needle

  • Leaf margin: serrated; lobed

  • Ochrea: Not Present

  • Stem hairs: no hairs; has hairs

  • Flower color: green; white

  • Growth habit: woody bush or tree; upright and nonwoody

  • Stem: round or oval

  • Leaf structure: pinnate

  • Leaf hairs: no hairs

  • Root structure: taproot; fibrous

  • Flower symmetry: not symmetrical

  • Flower diameter: pencil

  • Leaf stalk: shorter than leaf; none