1610s, from Latin herbalis, from herba "grass, herb" (see herb). Earlier as a noun, "book that names and classifies plants" (1510s).
Entries linking to herbal
herb n.
c. 1300, erbe "non-woody plant," especially a leafy vegetable used for human food, from Old French erbe "grass, herb, plant fed to animals" (12c., Modern French herbe), from Latin herba "grass, an herb; herbage, turf, weeds" (source also of Spanish yerba, Portuguese herva, Italian erba). The form of the English word was refashioned after Latin since 15c., but the h- was mute until 19c. Slang meaning "marijuana" is attested from 1960s. The native word is wort.
herbalist n.
"student of, or dealer in, herbs," 1590s, from herbal + -ist. Earlier such a person might have been called herber (early 13c. as a surname), herbarian (1570s), herbarist, herb-man, herbary (1540s). Fem. formation herb-wife is attested from 1580s.