"Herbalist" is, to me, a more relevant concept than "doctor of plants" (it would be interesting to investigate if there is a special word for "doctor of plants" in some language).
Hi .asiz.!
I believe your thinking of "gardener" or "florist" for someone doctoring on dead plants as well. Something like a plant necromancer? I love this language. Maybe you could add a particle to indicate the "using plants" component (pilno?), to make the "Herbalist" more unambiguous. But I don't know :)