When I first gained access to the couple of acres of pasture that I currently farm, my eyes would casually skim over the poly-culture of plants and grass-life, unable to differentiate one from another due to the vastness of the fields. I only gained insight into the nuances of the pasture once I started to rotationally graze my livestock. When using this method a farmer becomes intimately familiar with the many paddocks that are formed through the process, creating a magnifying lens focused on the different plant families. Rotating back to a paddock that the animals haven’t had access to in a month or two feels similar to visiting an old friend. Then things you haven’t noticed before start to take center stage.
Onto this stage stepped Purple Vetch (better known as Crown Vetch), a legume that’s used in agriculture nationwide as a cover crop because it fixes nitrogen in the soil. But the USDA recognizes it as an invasive species, growing unchecked throughout Oregon (it is what creates the large purple patches on the hills in the Rogue Valley during the spring and early summer). At the time I was excited to find it in abundance, happily fixing nitrogen on my land and providing quality forage for my livestock. I didn’t know that this plant was invasive until a friend brought it to my attention.
But over the next couple of years there seemed to be less and less of the vetch in every rotation. This plant that had grown throughout the region had started to disappear to my and my sheep’s dismay (the sheep loved to eat it). Pressure from the sheep’s grazing and chickens following behind cleaning up the seeds seemed to have created an environment that was in uninhabitable to vetch.Instead of changing the paddock system around to save what was left, I decided to allow events to play out. As I move in to my fourth season, there is no vetch anywhere on my pasture land. It only grows where the sheep cannot reach, on the neighbor’s side of the fence line. I have effectively (and unintentionally) eradicated purple vetch.