Dogfennel (Note: This is a common pasture weed, not a true grass)
Eupatorium capillifolium · Herbaceous Perennial (C3 Dicot, though often found growing with C4 grasses)
Grass Family
Asteraceae (Sunflower/Aster Family), Tribe Eupatorieae
Grass Category
Invasive/Weed Grass (Pasture and Disturbed Land Weed)
Variety / Cultivar
Native species (Common Dogfennel)
Hardiness Zones
USDA Hardiness Zones 3-10; extremely heat tolerant; dies back to the ground after a hard frost and regrows from the crown in spring.
About This Grass
A tall, erect herbaceous perennial reaching 3-6 feet. It has a feathery, fern-like appearance with a lime-green color. Though often growing among turf, it is a non-grass weed. It produces numerous tiny white flower heads in terminal panicles at maturity.
Blade Characteristics
Technically leaves, not grass blades: highly dissected, thread-like (filiform) segments; alternate arrangement (lower) and opposite (upper); soft, hairless texture; distinct fennel-like odor when crushed; no ligules or auricles (dicot anatomy).
Root System
Thick, woody taproot and lateral root system; becomes more difficult to pull as it matures; low thatch but high biomass production in summer.
Growing Information
Origin Region
Native to North America, particularly the Southeastern United States from Massachusetts to Florida and Texas
Growth Habit
Bunch-type; forms dense clumps from a woody base or short rhizomes, often appearing as a tall, feathery spire
Sunlight & Water Needs
Full Sun to Partial Sun; highly adaptable to various moisture levels but thrives in moist, sandy, or disturbed soils; high drought tolerance once established.
Mowing & Maintenance
Not intended for turf; in pastures, it is managed by frequent mowing (below 2 inches) to prevent seed set or through herbicide application. High maintenance level to eradicate from turf.
Special Characteristics
Highly competitive in overgrazed pastures; contains pyrrolizidine alkaloids which are toxic to livestock (though cattle usually avoid it due to the smell); excellent drought recovery.
Ecological Information
Native to the US; provides cover for small mammals; serves as a nectar source for various pollinators including moths and wasps; can be aggressive/invasive in poorly managed agricultural lands.