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Similar but less problematic plants:
Foeniculum vulgare Foeniculum vulgare
Plants that fill a similar niche:
Phytolacca americana Phytolacca americana
Lantana camara Lantana camara flower
Symphyotrichum pilosum Symphyotrichum pilosum var. pringlei
Eupatorium capillifolium has some common disease problems:
Powdery Mildew in Turf

Thoroughwort Eupatorium capillifolium

Other Common Name(s):

Other plants called Thoroughwort:

Previously known as:

  • Eupatorium leptophyllum
Phonetic Spelling
yoo-puh-TOR-ee-um kap-ill-ih-FOH-lee-um
This plant has medium severity poison characteristics.
See below
Description

Eupatorium capillifolium, or Dogfennel, is an herbaceous perennial weed in the Asteraceae (daisy) family with finely-dissected leaves that are very aromatic when crushed (an aroma that is unpleasant to some). The plant spreads in the landscape by wind blown seeds and spreading rootstocks, sometimes to the point of becoming invasive, so it is important to prevent plants from flowering. Seedlings emerge from spring through early autumn. Plants are difficult to remove and if not removed completely with hand weeding, plants will re-sprout from broken stems. Dogfennel is managed from seed by many broad-spectrum preemergence herbicides; however, herbicide efficacy rankings for this species are based on limited experimental data. 

Dogfennel grows rapidly in moist but well-drained soils in full sun to part shade, although it does best with some afternoon shade in hot summer climates. It tolerates most soil types including dry, sandy soils. Plants have good drought tolerance. North of USDA Zone 6, this plant is best given a thick winter mulch and planted in locations affording some protection from harsh winter conditions.

Dogfennel foliage is feathery and can sway gracefully in the wind in an ornamentally attractive manner. However, Dogfennel is poisonous and has been used as an insecticide and antifungal. Dogfennel is native to fields, clearings, woodland margins and roadsides from Florida to the coast to Massachusetts, but is sometimes confused with non-native fennel.. 

Diseases, Insects, and Other Plant Problems:

No serious insect or disease problems. However, you should watch for powdery mildew, aphids, slugs and leaf miner.

See this plant in the following landscape:
Cultivars / Varieties:
  • 'Elegant Feather'
    Sterile cultivar that does not produce viable seed and lacks the invasive characteristics of species’ plants.
'Elegant Feather'
Tags:
#drought tolerant#perennial#weed#weedy#fragrant leaves#toxic#wind tolerant#herbaceous perennial#native weed#perennial weed
 
Cultivars / Varieties:
  • 'Elegant Feather'
    Sterile cultivar that does not produce viable seed and lacks the invasive characteristics of species’ plants.
'Elegant Feather'
Tags:
#drought tolerant#perennial#weed#weedy#fragrant leaves#toxic#wind tolerant#herbaceous perennial#native weed#perennial weed
  • Attributes:
    Genus:
    Eupatorium
    Species:
    capillifolium
    Family:
    Asteraceae (daisy)
    Uses (Ethnobotany):
    An insecticide and anti-fungal. The entire plant is applied externally as a remedy for the bites of reptiles and insects.
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Seed
    Country Or Region Of Origin:
    Eastern Canada, Central and Eastern United States
    Distribution:
    Atlantic and Gulf coastal plain, Eastern mountains and Piedmont, Great Plains, North Central and Northeast. Bermuda, Bahamas.
    Wildlife Value:
    Attracts bees and wasps. Eaten by Florida's scarlet-bodied wasp moth, Cosmosoma myrodora, that feed on the plant while mature to store its toxins and ward off predators.
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Tolerates drought and poor soil
    Edibility:
    toxic
    Dimensions:
    Height: 3 ft. 0 in. - 6 ft. 0 in.
    Width: 2 ft. 0 in. - 3 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Native Plant
    Perennial
    Weed
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Arching
    Ascending
    Erect
    Growth Rate:
    Rapid
    Maintenance:
    Low
    Texture:
    Fine
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    High Organic Matter
    Loam (Silt)
    Sand
    Shallow Rocky
    Soil pH:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Available Space To Plant:
    3 feet-6 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3b, 3a, 4b, 4a, 5b, 5a, 6b, 6a, 7b, 7a, 8b, 8a, 9b, 9a, 10b, 10a
  • Fruit:
    Fruit Color:
    Red/Burgundy
    Fruit Value To Gardener:
    Showy
    Display/Harvest Time:
    Fall
    Winter
    Fruit Type:
    Achene
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Fruits are smooth achenes. Fruiting stems attractive in winter landscape.
  • Flowers:
    Flower Color:
    Green
    White
    Flower Inflorescence:
    Corymb
    Insignificant
    Flower Value To Gardener:
    Long-lasting
    Showy
    Flower Bloom Time:
    Fall
    Summer
    Flower Shape:
    Dome
    Flower Petals:
    4-5 petals/rays
    Bracts
    Flower Size:
    < 1 inch
    Flower Description:
    Flowers are small, greenish-white and borne in large flower heads at the tops of the stems. Blooms from September through November. The small, 3 to 5 flowered heads are numerous and arranged in large, leafy, pyramid-shaped end clusters (corymbs).
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Feel:
    Smooth
    Leaf Value To Gardener:
    Fragrant
    Leaf Type:
    Compound (Pinnately , Bipinnately, Palmately)
    Simple
    Leaf Arrangement:
    Alternate
    Opposite
    Hairs Present:
    Yes
    Leaf Length:
    < 1 inch
    Leaf Description:
    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.
  • Stem:
    Stem Color:
    Brown/Copper
    Stem Is Aromatic:
    Yes
    Stem Form:
    Straight
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Long feathery stalks. Stems are erect, reaching 6 feet in height with a woody base. Unpleasant odor when broken.
  • Landscape:
    Landscape Location:
    Meadow
    Naturalized Area
    Woodland
    Landscape Theme:
    Native Garden
    Pollinator Garden
    Winter Garden
    Design Feature:
    Accent
    Border
    Attracts:
    Pollinators
    Resistance To Challenges:
    Drought
    Dry Soil
    Rabbits
    Problems:
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    Medium
    Poison Symptoms:
    Contains liver-damaging alkaloids.
    Poison Toxic Principle:
    Alkaloids such as lycorine
    Causes Contact Dermatitis:
    No
    Poison Part:
    Bark
    Fruits
    Leaves
    Roots
    Stems