Culture
Winter hardy to USDA Zones 6-9 where it is easily grown in moist but well-drained soils in full sun to part shade. Best with some afternoon shade in hot summer climates. Tolerates most soil types. Tolerates dry, sandy soils. Plants have good drought tolerance. In the northern parts of Zone 6, this plant is best given a thick winter mulch and planted in locations affording some protection from harsh winter conditions. Spreads in the landscape by wind blown seeds and spreading rootstocks, sometimes to the point of becoming invasive.
Noteworthy Characteristics
Eupatorium capillifolium, commonly called dog fennel, is a somewhat weedy, North American herbaceous perennial which typically grows on erect slender stems to 3-6’ tall with a spread to 3’ wide. It is native to fields, clearings, woodland margins and roadsides from Florida to Texas extending northward to Missouri, Kentucky, Pennsylvania and along the coast to Massachusetts.
Each plant produces several tall, stiff, woody-based, often reddish, upright stems clad with crowded, feathery, finely-dissected leaves which are pinnately divided into thread-like segments. Leaves are unpleasantly aromatic when crushed. Minute, greenish-white, somewhat ornamentally insignificant flowers bloom in late summer. The small, 3-5 flowered heads are numerous and arranged in large, leafy, pyramid-shaped end clusters (corymbs). Flowers bloom between September and November. Fruits are smooth achenes.
Genus name comes from the Greek name for these herbaceous and shrubby plants in honor of Mithridates VI Eupator, 132-63 B.C., King of Pontus, who reportedly discovered the medicinal uses for some Eupatorium species plants.
Specific epithet means hair-like in reference to the thread-like (filiform) leaves.
‘Elegant Feather’ is a sterile cultivar that will not produce viable seed, and accordingly lacks the invasive characteristics of species’ plants.
Problems
No serious insect or disease problems. Watch for powdery mildew. Watch for aphids, slugs and leaf miner.
Uses
Foliage sways gracefully in the wind in an ornamentally attractive manner. Borders. Open woodland gardens. Cottage gardens. Interesting backdrop.