By Ben Beckman
Late summer always seems like a time when weeds can become quite noticeable in pastures. Are you prepared to handle this late-summer nuisance?
Perennial weeds like western ragweed, ironweed, and verbena, as well as annual weeds like horseweed, sunflowers, snow-on-the-mountain, and buffalo bur can be plentiful in some pastures. In areas of pastures that have relatively thin grass stands, where animals congregate, or if overgrazing has occurred, weeds can be very visible.
Spraying weeds now does little good. Many weeds are too large to kill with herbicide. On both annual and perennial species that produce seed, herbicides might only reduce some seed production. If the goal is to improve appearance, shredding areas that have an abundance of weeds might actually be the best option, and may reduce some seed production too, if it’s not already too late.
Two other approaches are better for long-term weed control. First, focus on the grazing management of your pastures. This includes using the proper stocking rate and developing a good rotational grazing plan. An important objective is to increase the health, vigor, and density of your grass. Healthy, competitive grass stands are essential to reduce weed populations economically over time.
Second, target herbicide applications for when they will do the most good. Both perennial and annual species can be better targeted with a spring application when plants are smaller and able to be controlled. For perennials, if a second application is needed, waiting closer to a killing frost is best. This provides the double whammy of stressing the plant heading into winter and allows more product to be translocated down to the shoots and roots as nutrients are pulled down for winter storage. Proper identification of your problem weeds is crucial when making these application timing decisions.
Pasture weeds may look unsightly now, but hold off on spraying. Improve grazing management and time herbicides for the best window of control so herbicides won’t be needed as often in the future.