Managing Perennial Weeds in Pastures and Hayfields This Fall

By Andi Anderson

Fall is a critical season for farmers and livestock producers looking to improve the health and productivity of pastures and hayfields. Perennial weeds, such as Canada thistle, hemp dogbane, and milkweed, can significantly reduce forage quality if left unmanaged.

These species are especially difficult to control because of their deep and resilient root systems that allow them to quickly regrow after being cut or treated.

The challenges of 2025, including the lingering effects of last year’s drought, have led to an increase in perennial weed pressure across many forage fields. This has made fall management practices even more important for maintaining forage productivity.

Fall is considered the best window for controlling perennial weeds. During this time, plants naturally begin to store energy in their underground root systems in preparation for winter.

Management efforts in the fall—whether mechanical, cultural, or chemical—are more effective because they directly reduce the energy reserves these weeds rely on to regrow in the spring.

Mechanical control methods, such as frequent mowing, can help weaken perennial weeds by depleting their carbohydrate reserves. Over time, this repeated stress reduces the weeds’ ability to regrow.

Chemical control, when applied correctly in the fall, is also more effective because systemic herbicides are pulled into the root system along with the plant’s stored nutrients.

Producers are encouraged to combine control strategies for the best results. Regular monitoring, timely mowing, and targeted herbicide applications can work together to reduce weed populations and improve forage quality.

By taking action in the fall, farmers not only reduce next year’s weed pressure but also protect the health of their livestock by ensuring better forage stands.

With careful planning and consistent efforts this fall, perennial weeds can be managed more effectively, helping farmers maintain productive pastures and hayfields into the next growing season.

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