How can I manage Canadian thistle, dog bane, and multiflora rose in my permanent pastures in Wisconsin?
Answer: Canadian thistle can be controlled by clipping the thistle at the flower bud stage, most likely around mid-July for Wisconsin. By so doing, you have let the plant expend energy in growth and producing a seed head, which is demanding upon its root reserves. When you clip it at the bud stage, it will regrow, but in the northern climes, it will not be able to produce seed before it is killed out by frost in the late fall. After two or three years of this, the plant is weakened enough that it dies out. You can tell the stage of this debilitation each year by noting how tall the thistle plant is when it starts to bud. Healthy plants will be two to three feet tall at bud. Plants that are on their way out will be less than a foot high. It is a good way to monitor your progress.Of course, the second principle behind this is to never let the thistle produce viable seed. However, if it does, it is still better to clip the thistle in the mature seed stage than to not clip it at all.Dogbane and multifora rose can be treated the same way. Clipping in the early flower stage will go a long way to controlling these two weeds.Additionally, if you have access to a no-till drill, one could consider haying your field and then immediately drilling in a cover crop mix such as hairy vetch, oats, cow peas, tillage radish, and annual ryegrass in the worst areas of the weed infestation. This would put competition and shading pressure on the weeds and hasten their demise.For more information, see the following ATTRA publications on pasture management:Pastures: Sustainable Managementhttps://attra.ncat.org/attra-pub/summaries/summary.php?pub=247Pastures: Going Organichttps://attra.ncat.org/attra-pub/summaries/summary.php?pub=179