Extended Strong's Greek Lexicon (Abbott-Smith based)
hyssop
Usage: ὕσσωπος, -ου, ἡ [in LXX for אֵזוֹב ;] hyssop, of which a bunch was used in ritual sprinklings: Heb.9:19; of a branch or rod (?) of hyssop, Jhn.19:29 (but see Field, Notes, 106 ff., for suggestion to substitute ὑσσῷ here).† (AS)