Often, rosettes can be sprayed again in the spring before new legume seedlings have emerged. Broadleaf weeds such as ironweed and goldenrod can be controlled with a sponge or rope-wick applicator when they are above the height of the desirable pasture. Plan to apply herbicide prior to bloom stage of perennial weeds for good control. Follow all label grazing restrictions whenever using a herbicide on pasture. With any form of weed control, timing is critical.
Many weeds have a narrow window of opportunity for control - with or without herbicides.
For annual weed management the goal is prevention of a new seed crop. Perennial weeds must either be killed or weakened to the point that they are no longer a problem. The best strategy for improving pastures is to implement a well planned grazing management system that maintains proper stocking rate on the pasture and provides a rest period for individual plants to maintain their vigor. A planned grazing program helps maintain N-fixing legumes in the pasture to supply free N into the system. The healthy pasture will better compete to prevent weed seedlings from establishing in open spots where sunshine reaches the soil surface.