Sept. 4, 2015

Weeds have exploded recently in many pastures.  Plants like ragweed, ironweed, goldenrod, and vervain are abundant everywhere.  Where did your weed management efforts falter and what can you do now?

Abundant summer rains stimulated growth of these weeds.  Even seemingly well-managed pastures have problems, often in areas that were grazed while soils were wet and soft.  Cattle trampling is these spots opened areas for weeds to get started.  Only pastures or areas in pastures with thick, relatively tall grass stands have few weeds.

Spraying many of these weeds now does little good as they are too large to kill. A herbicide application may reduce seed production and make pastures a bit more attractive, but shredding would actually work better to reduce weed seeds if it's not already too late.

Two other approaches are more important for long-term weed control.  First, do more rotational grazing next year to improve the health, vigor, and density of your grass.  As you rotate, leave more residue behind when moving animals to a new pasture to maintain higher competition.  Healthy, competitive grass stands are essential to reduce weed populations economically.

Second, target herbicide applications for when they will do the most good.  Late May to early June usually is most effective with most  pasture herbicides.  Most perennial weeds, and many annuals, are sensitive to chemicals in June. Weed control, along with good grazing, will thicken your grass stands so herbicides won't be needed as often in the future.

Don't let weeds take over your pasture, but don't spend money controlling them needlessly.  A good, long-term plan will work best.

Bruce Anderson
Extension Forage Specialist