Zanthoxylum clava-herculis, Hercules' club (or Hercules-club), pepperwood, or southern prickly ash, is a spiny tree or shrub native to the southeastern United States. It grows to 10–17 m tall and has distinctive spined thick, corky lumps 2–3 cm long on the bark. The leaves are glabrous and leathery,pinnately compound, 20–30 cm long with 7-19 leaflets, each leaflet 4–5 cm long. The flowers are dioecious, in panicles up to 20 cm long, each flower small, 6–8 mm diameter, with 3-5 white petals.