Herbalist

n. one who collects or grows herbs (especially for their medicinal qualities); herb doctor

An herbalist is:A person whose life is dedicated to the economic or medicinal uses of plants.One skilled in the harvesting and collection of medicinal plants (see wildcrafter).Traditional Chinese herbalist: one who is trained or skilled in the dispensing of herbal prescriptions; traditional Chinese herb doctor. Similarly, Traditional Ayurvedic herbalist: one who is trained or skilled in the dispensing of herbal prescriptions in the Ayurvedic tradition. One trained or skilled in the therapeutic use of medicinal plants.
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Noun
1. a therapist who heals by the use of herbs
(synonym) herb doctor
(hypernym) therapist, healer

(n.)
One skilled in the knowledge of plants; a collector of, or dealer in, herbs, especially medicinal herbs.
  

One versed in herbal lore and, in regard to therapy, an herb doctor.