Zanthoxylum is a genus of about 250 species of deciduous and evergreen trees and shrubs in the citrus or rue family, Rutaceae, native to warm temperate and subtropical areas worldwide. Common names also include Prickly-ash and Hercules’ Club. The fruit of several species are used to make the spice Sichuan pepper. They are also used as bonsai trees. Historically, the bark was widely used for toothache, colic, and rheumatism.

Zanthoxylum davyi or Knobwood as it is commonly known is a tree that can reach 8 to 30 meters is height in open soil. It has wrinkled grey-brown bark covered with horn-like knobs and shiny green leaves. During spring it bears small greenish white flowers which are followed by lemon scented fruits. The knobwood will attract lots of birds to the garden.