One Person’s Weeds

When I arrived at our farm in 2007, about 60 acres of it was enrolled in the U.S. Department of Agriculture’s Conservation Reserve Program (CRP). The contract ran for a few years after I bought it and offered a small bit of income in the form of an annual government check. I wasn’t happy about the contract, as I had plans for the acreage, but you do what you do. The plant matrix in the CRP wasn’t impressive — there was little diversity, other than perhaps five species of grasses. Oddly, there were almost no broadleaf plants in those acres, and there were some bare patches. Weedy species, such as nodding thistle and Lespedeza cuneata, known as “sericea lespedeza,” were the most prevalent non-grass plants out there. After some research, I learned that the seed mix was contaminated with the sericea, which was a problem for our entire county, as it’s an aggressive competitor in warm-season meadows and pastures.

I waited out the contract and did my best to beat back the weeds with digging, flaming, and even a bit of spot-spraying. The thistles were easy to manage, but the sericea was more persistent. Nonetheless, I managed to keep it from spreading by mowing it before it went to seed, and I noticed that wherever I mowed it, volunteer cool-season grasses and some warm-season grasses moved in. The year the CRP contract was up, I moved my sheep onto the areas with sericea, and they grazed it, as did the cattle. As long as it was soft and lush, they ate the sericea. While researching sericea control methods, I discovered a paper published by scientists at Kansas State University that suggested that goats were the only way to eradicate the weed, because they would seek it out and preferentially eat it all season long. We had no goats, but we had lots of sheep well-trained to portable electric fencing, so we implemented a rotational grazing strategy that kept the sericea vegetative for most of the year. And where the sheep didn’t graze, we made hay long before the sericea went to seed. The stands of the weed thinned and shrunk. And while the sericea was indeed being set back, our sheep thrived and carried a much-reduced parasitic worm load — ostensibly from anthelmintic compounds in the sericea leaves.

Today, we’re experimenting with drilling aggressive spring and fall annual crops, such as buckwheat, grazing collards, cereal rye, and chickling vetch, into the worst areas before the sericea wakes up in spring or is grazed to the ground or hayed off in fall. These so-called “smother crops” reduce the competitive advantage of the weed, build soil, and offer some late- and early-season grazing for the sheep. We’ve also added perennial legumes and grasses to the seed mix that we hope will add diversity and productivity to the pasture matrix going forward. We likely won’t eradicate the sericea, but the benefit it provides to the sheep means we don’t want it gone completely. We’ve discovered that this weed, which can be a serious problem in our area, can also provide a benefit when not left to spread out of control.