tar weed is taking over our pasture
We have about 5 to 6 acres of pasture outside of town in Eugene that is being taken over by tar weed. We have two horses which we are keeping on our other pasture which doesn't have tar weed yet. The weeds will be coming into bloom any day. What is the best way to get rid of it so we may possibly put horses back on it. The acreage has not been mowed since last Fall or grazed since this past March. Should we mow the fields now, then spray with some type of weed killer soon after? We would greatly appreciate any help you can give us.
At this point in the summer and the fact that the tarweed will be blooming soon, I recommend mowing the field to keep the plants from generating new seed. Herbicide treatments will be most effective on tarweed when the plants are young and actively growing. Plan to walk your pastures and identify plants next spring and apply an herbicide treatment, if needed then. Milestone is a herbicide to consider applying to your horse pasture as it is effective on broadleaf weeds. Please be sure to read the label and follow instructions prior to application.
For more information about pasture and grazing management strategies for horse farms, check out:
Managing Small-acreage Horse Farms for Green Pastures, Clean Water, and Healthy Horses at http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/19670/ec1558.pdf