By Andi Anderson
August has arrived, and with it comes the peak bloom of spotted knapweed — an invasive weed now found along Eastern Ohio’s roadsides, pastures, hayfields, and open spaces. Known for its aggressive spread, spotted knapweed can quickly overtake weaker stands of desirable plants.
The plant’s pinkish-purple flower resembles red clover in color, chicory in growth habit, and Canada thistle in shape, making it difficult for many to identify.
Its life cycle is similar to a biennial, producing no flowers in its first year, then flowering in the second year and beyond. Left uncontrolled, its prolific seed production can lead to a population surge within a year.
Mature seed heads resemble Canada thistle, with clusters of seeds topped by a fluffy pappus that aids in dispersal by wind, water, animals, and vehicles. With few natural predators in Ohio and a tolerance for marginal soils, the weed thrives in many environments.
Control methods include timely herbicide applications in grass pastures, which have proven more effective than mowing. Recommended products with good to excellent results include:
- GrazonNext HL at 2 pints per acre
- Milestone at 5–7 fluid ounces per acre
- Clopyralid 3 at 2/3–1 pint per acre
Mowing can help reduce seed production but may not prevent flowering, as plants can bloom below mower height. As with any herbicide use, applicators should read and follow all label instructions, including restrictions on grazing, harvest intervals, and movement of hay or animals.
Heavy stands of spotted knapweed are currently visible along I-77 in Belle Valley and other roadside areas. Reducing its spread will require a community-wide effort, with landowners addressing infestations on their own properties and raising awareness of its impacts.
By working together and taking timely action, Eastern Ohio can limit the spread of this invasive plant and protect productive land from its competition.
Photo Credit: gettyimages-zoomtravels
Categories: Ohio, Rural Lifestyle, Farm Safety