Eupatorium capillifolium
dogfennel
Southeastern and eastern United States
Overview
Eupatorium capillifolium is an upright herbaceous perennial in the family Asteraceae, growing 3-10 feet (0.9-3 m) tall on slender, much-branched stems that rise from a woody base. The foliage is finely divided into thread-like segments, giving the plant a feathery, fennel-like look, and releases a pungent scent when crushed. From late summer into autumn the upper stems carry open, plume-like sprays of tiny greenish-white flower heads, each only about 0.1 inch (2-3 mm) across. The minute seeds bear tufts of bristles that carry them on the wind, and a single plant can produce many thousands. Eupatorium capillifolium colonises old fields, pastures, roadsides, and disturbed ground, often forming tall stands. The foliage contains pyrrolizidine alkaloids that are toxic to grazing animals and people if eaten. Limitations include a weedy, short-lived habit, prolific self-seeding, and stems that turn brown and untidy after flowering.
Native Range
Eupatorium capillifolium is native to the southeastern and eastern United States, from New Jersey south to Florida and west to Texas, with naturalised populations farther afield. It grows in open, sunny, disturbed habitats such as abandoned fields, pastures, ditches, and sandy roadsides.Suggested Uses
Eupatorium capillifolium is used in meadow, prairie, and naturalised plantings and for quick cover on poor, disturbed soil, spaced 2-3 feet (60-90 cm) apart. Its feathery texture suits informal, wild settings rather than tidy borders, and the dried plumes are cut for arrangements.How to Identify
Appearance
Size & Dimensions
Height3' - 10'
Width/Spread1' - 3'
Reaches mature size in approximately 1 years
Bloom Information
Eupatorium capillifolium blooms in late summer and autumn, roughly September to November, when the upper stems open into feathery sprays of tiny flower heads. The flowers are wind-pollinated and not showy, relying on air movement rather than insects. Seed ripens quickly and disperses on the wind through late autumn.
Detailed Descriptions
Foliage Description
Bright green, finely dividedGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Eupatorium capillifolium grows in full sun on a wide range of soils, from sand to clay, and tolerates poor, dry ground as well as seasonal moisture. It establishes easily from seed and often appears on its own in disturbed soil. Drought-hardy once rooted, it needs no irrigation in its native range. Cutting plants back before seed sets limits the heavy self-sowing that can crowd a planting. Few pests or diseases affect it. No fertiliser is needed, as lean soil keeps growth more compact.Pruning
Eupatorium capillifolium can be cut back hard in late spring to reduce its height and create a denser, bushier form. Stems are cut to the ground in late autumn or winter once they brown. Removing the flowering plumes before seed matures is the main way to control its spread.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
late spring