 Bull thistle (Cirsium vulgare), common mullein (Verbascum thapsus), and Klamath weed (Hypericum perforatum) have been identified as noxious pests in Yosemite since the 1940s. Additional species that have been recognized more recently as aggressive and requiring control are yellow star thistle (Centaurea solstitialis), sweet clover (Melilot spp.), Himalayan blackberry (Rubus armeniacus), cut-leaved blackberry (Rubus laciniatus) and large periwinkle (Vinca major).
