Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
herbācĕus, a, um, adj. [herba], grassy, grass-colored, grass-green, Plin. 19, 6, 33, § 110; cf.: folia herbacei coloris, id. 20, 13, 51, § 134: flos, id. 21, 19, 75, § 128 (opp. albus), id. 26, 8, 35, § 55: oleum, id. 23, 4, 49, § 95: chrysocolla, id. 33, 5, 27, § 90.