Rumex crispus, also called curly dock, is a robust tap-rooted perennial growing two to five feet tall. Stems are erect, reddish, and slightly ridged. The elongated, basal leaves grow from 4 to 12 inches long and have wavy margins and lack hairs.

Small flowers emerge in dense, green, spike-like, terminal clusters. Entire plants may turn reddish-brown at maturity. Individual seeds are enclosed in a papery-to-corky winged structure that facilitates spreading by wind or water. 

Dock species are native to Eurasia. They are particularly common in wet meadows, along ditch banks, and in waste areas.