Two species of rabbitbrush occur in central Washington, the predominate one commonly called "grey" rabbitbrush. It has greyish "hairs' covering the stems and leaves, giving it a greyish appearance. The other is called "green" rabbitbrush, which does not have those hairs and looks greener.

Thanks lea-p. And David, yes. Follow the links to the previous entries, I believe one of them mentions the synonymy.

Hmm.. nope. There were wild roses in the area, if I recall correctly - that's a possibility.