Southern Prickly Ash

(Left) Southern Prickly Ash, Zanthoxylum clava-herculis

Southern Prickly Ash grows along streams from Texas up through southern Virginia. It is taller than the Northern, or Common, Prickly Ash, Zanthoxylum americanum, reaching heights close to 14 m (45 ft) instead of the 8 m (25 ft) of its relative. Leaves range from 5 to 17 leaflets and small, green flowers appear during the early summer; however, the most characteristic feature is the sharp spines on the bark.

Also called Toothache Tree, Tingle Tongue, Hercules' club, and Pepperwood

Another common name for southern prickly ash is toothache tree due to the numbing effects of its bark, and its most frequent medicinal use among the Native Americans. This anesthetic property is the elicited by hydroxy-α-sanshool which activates a variety of sensory receptors including mechanoreceptors and nociceptors. It also inhibits anesthetic-sensitive potassium channel sub-types. Sichuan pepper also elicits a similar response as it is a spice derived from two plants of the same Zanthoxylum genus; however, it should be noted that this is a plant defensive mechanism. Just as the spines offer a mechanical defense, the chemicals within the bark offer a chemical defense from harm.


This month I'm doing a tour of bark found in North Texas (which includes natives and non-natives). If you would like to try identifying the bark beforehand, I'll be posting the photos first on Google+ each Monday and Wednesday for anyone and everyone to guess.