I was browsing your website and noticed that St. John's wort can't be sold in Yolo and was wondering why. I have some seeds of another Hypericum (punctatum) and want to know if I should worry about planting them or not, since it seems like a similar species.
H. perforatum is considered a noxious weed threatening rangeland in California, and sale in Yolo County is forbidden by the County Agricultural Commissioner. Management of weeds in that category is at the discretion of each county's ag commissioner, so other counties may allow them. You are not restricted from growing a different species; there are many other species of Hypericum that can be sold (and are not considered invasive). For example, H. perforatum and H. canariense are on the invasive plants database. Your species is not.
Here is a reference link: cal-ipc.org
Here is an article about true invasives and mere garden thug