Lewis & Short

hȳsōpum (hysso-), i, n., = ὕσσωπος, hyssop: Hyssopus officinalis, Linn.; Plin. 25, 11, 87, § 136; 26, 11, 70, § 114; 26, 12, 76, § 124: asperges me hyssopo, et mundabor, Vulg. Psa. 50, 8 al.
And in a form corresp. to the Gr., hyssōpus, i, f., Cels. 4, 8; Col. 7, 5 fin.
Also scanned hȳsŏpum, Aemil. Mac. de Hyssopo.