So this is what I found in my hayfield last week. There were about a dozen plants in one small area. This is the first time I’ve seen it in my fields. Russian knapweed is a pernicious invasive weed. It is toxic to horses. A marvelous find in my horse hay field.
The first time I saw this stuff was last year in a mown field on the coast. It had taken over large portions of the field. The weed is a perennial that spreads mostly through the roots. It also produces plenty of seeds.
Knapweed is native to southern Russia, Ukraine, Iran, Kazakhstan and Mongolia. Its roots even grow in the winter. The weed produces poison that kills other plants so that it forms dense monocultures.
Eradication is difficult. The roots can cover six square yards in a growing season. The recommended way to control it is to kill it with herbicide then plant grasses that can survive its poison to out-compete it. Repeated manual removal to stress the roots, along with encouraging grass growth through irrigation is an organic control method.
My farm is organic. I pulled all the growth as soon as I found it. The field will be mowed in the next few weeks. That will make it easier to spot re-emerging growth.
I plan to stay on top of this weed and stress the heck out of the roots.
Who knows how Russian knapweed got in my field. I suspect it was brought in on haying equipment used by the farmer who cuts my hay. That’s how yellow rattle invaded my fields.
By manually removing all the rattle before it can seed, I nearly eliminated it. Unfortunately, the farmer brings in more each year. I have to patrol my fields every spring looking for rattle and ripping it out. I spotted the knapweed while I was looking for rattle. Patrolling the hayfields has become an essential part of farming for me, it seems.
I hope one day soon to own haying equipment. Cutting my own hay will make my life easier in many ways, including reduction in the numbers of invasive weeds.