Dogfennel (Not a true grass)
Eupatorium capillifolium · Perennial broadleaf herb, C3 photosynthetic pathway (Often mistaken for grass)
Grass Family
Asteraceae (Sunflower family)
Grass Category
Invasive/Weed, Pasture Weed, Ruderal Species
Variety / Cultivar
Native species, no specific cultivar identified in the image
Hardiness Zones
USDA Zones 3-10; thrives in warm temperate and subtropical climates; dies back to the ground after heavy frost.
About This Grass
An upright, herbaceous perennial that can reach 3-6 feet. It features extremely fine-textured, bright green foliage that is highly branched and feathery. While it looks like a grass from a distance, it is a broadleaf plant. It produces small, white, inconspicuous flower heads in late summer/fall.
Blade Characteristics
Leaves are deeply pinnately divided into filiform (thread-like) segments. They are not true grass blades and lack ligules/auricles. They have a strong, pungent odor when crushed.
Root System
Deep woody taproot and lateral rhizomes; very difficult to pull once established; does not form a turf sod.
Growing Information
Origin Region
Native to North America (specifically the Eastern and Southern United States)
Growth Habit
Clump-forming perennial with a woody base and aggressive underground rhizomes
Sunlight & Water Needs
Full sun; drought-tolerant once established; prefers well-drained, sandy or disturbed soils but adaptable to various moisture levels.
Mowing & Maintenance
In pastures, frequent mowing prevents seed production but does not easily kill the plant due to its woody base. Not suitable for lawn heights; maintenance involves herbicidal control.
Special Characteristics
Toxic to livestock if consumed in large quantities (contains pyrrolizidine alkaloids). Highly resistant to many common herbicides and very competitive in poor soils.
Ecological Information
Native to North America; provides cover for small birds and mammals. It is considered a weed in agricultural settings and an invasive colonizer of disturbed sites.