Why is it a problem?
- Spreads by seeds (1,300-4,000 per plant that can remain viable over 20 years) and rhizomes
- Spread by wind, animal droppings, contaminated seed, and with timber
- Common in roadside ditches, disturbed sites, beach meadows, landscaped spaces
- Decreases plant diversity and potentially increases erosion
- Creates dense stands and can quickly replace half the grasses in a pastur
- Unpleasant odor—not grazed by animals and toxic to insects
- Hosts chrysanthemum stunt virus, aster yellows virus, tomato aspermy virus, and several nematode species
How do I manage this plant?
- Dense groundcover inhibits establishment
- Avoid trampling, mowing, and cutting, as these promote establishment
- Intensive cultivation provides control
- Nitrogen fertilizers are nearly as effective as herbicides
- Herbicides are effective