The stalks of the madder plant are prickly and can grow up to eight feet, but are often too weak to support their height. The flowers are yellow, but only bloom at the start of summer once every 2 - 3 years.
The roots are used as a dye, and the older the root is the better (typically 3+ years before use). The outer layer of the root is black, under the surface is red and the pith is yellow. The outer layer is discarded, and the inner layers are dried and powdered to be used to create red, purple, organge and black. If the root is eaten, be warned, it will turn your urine your red!
The leaves have spines on their underside, and have been used to polish metalwork.