Charles Ellicott Commentary Leviticus 13:49

"if the plague be greenish or reddish in the garment, or in the skin, or in the warp, or in the woof, or in anything of skin; it is the plague of leprosy, and shall be showed unto the priest." — Leviticus 13:49 (ASV)

And if the plague be greenish. — If one of these symptoms manifests itself in a woolen or linen garment, or in a leather vessel, it must immediately be shown to the priest. The Jewish canons define the color of the green symptom to be like that of herbs, and that of the red to be like fair crimson.