Invasive Watch: Kochia

Kochia is a tough summer annual broadleaf weed that first emerges in early spring and continues to germinate throughout the summer. 

What to Look For

Kochia (kochia scoparia) is a summer annual broadleaf weed that first emerges in early spring and continues to germinate throughout the summer. Its seedlings have a silvery-green, fuzzy appearance, which makes the plant easily mistaken for fivehook bassia. During the rosette stage, kochia has an erect, multibranched stem and can have purple stripes. Once fully grown, its branches stretch 3 to 7 feet long, forming a cone shape. Its many slender green leaves are 1 to 2 inches long, alternate and lance-shaped, with hairy margins and undersides. When blooming, kochia has thousands of inconspicuous clustering flowers found on the axils of upper leaves.

Where It Is Found

As a drought-tolerant weed with a hardy root system, kochia easily infests very dry, disturbed sites. It is most common in the western portion of the United States in cultivated fields, pastures, gardens, rights-of-way, ditch banks and waste sites. As it matures, kochia dries out, allowing for the wind to break and carry off the upper portion of the plant, spreading its seeds rapidly and widely.

How To Treat It

Herbicides can be used to effectively remove and eliminate kochia. Elimination and complete eradication are possible but require a commitment to a program approach and can take multiple years to achieve.

One excellent option to treat kochia is Vista® XRT herbicide. Spray 12 fluid ounces per acre of Vista XRT directly onto kochia foliage, including the growing tips and terminal bud. Ensure adequate coverage on all of the plant’s foliage. For optimum control, add a methylated seed oil surfactant (MSO) at the rate of 1 to 2 quarts per acre. For infestations of larger plants at more advanced growth stages, increase the amount of Vista XRT to up to 22 fluid ounces per acre, or add 1 to 2 quarts of 2,4-D along with the 1 to 2 quarts of MSO to improve control.

Apply the herbicide solution at a volume that wets the foliage, but not to the point of runoff. Apply foliar treatments between May and September, as long as the plants are actively growing and not under drought stress. Optimum timing is when the plants are between 4 and 12 inches tall.

For additional control, consider adding Freelexx® herbicide at 2 to 4 pints per acre. Apply before the bud stage, when annual weeds are small and growing actively. Biennial and perennial weeds should be rosette to bud stage, but not flowering at the time of application.

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