Not sure of answer to your question, but just wanted to sympathize about Russian Yellow Star Thistle. God that stuff's nasty. If we planted it along the border, no illegals would ever get through. Neighbor's rotweiller stepped on one with rear paw and needle migrated up leg and all the way to upper ribs, causing massive infection. When vet cut it out, it was still hard and sharp as a hypodermic needle.
I cut some with the brush hog a few years ago and breathed the pulverized dust. Within hours I came down with bronchitis so bad that it induced asthma, which I had never had before. I always wear heavy duty air filter & goggles now.
Nice to hear more Central CA folks on here.