Brassica oleracea var. viridis L. Chou cavalier is also known as caulet, chou collard, chou en arbre, chou fourrager, chou vert or chou kale, although other brassicas have those names too, and kale in partcular is different.
All are hardy and grow on ‘trunks’ and are often raised for animal feed. Sometimes the leaves are used in soups such as garbure.
Image by Evan-Amos