Hay Fields Hit Hard by Weeds

By Andi Anderson

Weather extremes across Ohio have created difficult conditions for pastures and hay fields this year, leading to unusual weed growth. Both excess rainfall and drought have weakened grasses and legumes, opening gaps for invasive and toxic species to thrive.

Weeds such as ragweed, cocklebur, ironweed, Carolina horsenettle, nimblewill, and perilla mint have all become more common. Opportunistic weeds use bare soil and reduced competition to spread rapidly, especially when desirable forages are stressed or go dormant.

Nimblewill has been particularly aggressive this season. This warm-season grass grows well in hot, wet conditions and often takes over shaded or poorly drained ground.

It spreads quickly through stolons, filling gaps left by struggling cool-season forages. Management strategies include soil testing, reseeding cool-season grasses in the fall, and short-duration grazing to reduce infestations.

Perilla mint has also become a growing concern. Once limited to shaded areas, it is now appearing in open fields. Its toxicity poses severe risks to livestock, as all parts of the plant can cause fatal respiratory problems.

Controlling its spread requires mowing, herbicide use, or maintaining dense forage stands. Farmers are advised to scout regularly and remove plants before they go to seed.

Weed control decisions depend on coverage. If weeds cover less than 10% of an area, mowing or grazing adjustments may work. Between 10% and 20%, spot-treating is often needed, while above 20%, herbicides or more aggressive control are usually required.

To improve forage systems, mixes of oats, brassicas, and cereal rye offer extended grazing opportunities. These rotations improve pasture recovery, reduce compaction, and extend the grazing season into late fall and early spring.

Ohio farmers are encouraged to remain proactive with scouting, soil fertility management, and rotational grazing. By planning ahead and keeping forage stands strong, pastures and hay fields can better resist weeds despite challenging weather.

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