Kochia
Bassia scoparia
Washington State Classification
Class B — Control Required (Designated)
In areas where kochia is widespread, it is considered a serious pest of late-maturing crops.
Required control in Region 1 (all western Washington counties)
Quick Reference
Identification
Growth Habit
Kochia is an annual herbaceous plant that has a deep taproot and grows 1.6 to 4.9 feet tall. Kochia stems are upright and spreading with many branches.
Leaves
Kochia leaves are alternately arranged and are 1 to 2 inches long. They are narrow to lance shaped with smooth, hairy edges and may have silky hairs on leaf undersides.
Flowers
Flowers are small and green, grouped in clusters in the upper leaf axils and on terminal spikes.
Fruit & Seeds
Each flower forms a small inflated seed bearing structure that is covered by the sepals. Seeds are wedge-shaped and light brown.
Impact
In areas where kochia is widespread, it is considered a serious pest of late-maturing crops. Kochia is an effective competitor for light, nutrients, and soil moisture, and can reduce crop yield.
Ecology & Spread
Habitat
Kochia is found on pasture, rangeland, roadsides, ditch banks, wastelands and cultivated fields. Please click here to see a county level distribution map of kochia in Washington.
Spread Mechanisms
Reproduction
Kochia reproduces from seeds, it typically produces around 14,600 seeds per plant. Seeds are dispersed in the fall when the plant becomes a tumbleweed.
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Control Methods
Mechanical
- Mowing or slashing the plants before flowering is effective in reducing seed production.