There are many plants called hyssop. After much discussion, it is now thought to be origanum maru, which is also known as the Syrian or white marjoram, which would have been indigenous to the Promised Land and its environs. They are fragrant, wiry plants, up to three feet in height, but much less when growing, as they often do, in rocky crevices or poor soil. Solomon bears this out when he said of hyssop that springs out of walls (1 Kings 4.33). Their branches and leaves are hairy and the flowers are white. As they are hairy they hold water well. This is why they were used as sprinklers in religious ceremonies. Moses directed that the 'hyssop' be used to sprinkle the blood of the Passover lamb on the doorposts of the Hebrew homes in Egypt. (Exo.12.22).

Also it was used to cleanse the lepers as in Leviticus 14. "Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter than snow". Psalm 51.7.

Hyssop also appears in John 19.29 "a jar full of sour wine stood there, so they put a sponge full of the sour wine on a hyssop branch and held it to his mouth" (ESV). According to botanists and John Chancellor, this would have been a reed as origanum maru would have been too small.