Cabbage is a biennial plant. Having dense leaved heads, it is grown as an annual crop. Being a descendent of Brassica oleracea var. oleracea (wild cabbage), It is a different cultivar but the same species of Cole crops such as broccoli, kale, and cauliflower.
Read this full article on how to grow Ornamental Cabbages in your garden. It's a very common cruciferous vegetable that everyone should add to their growing plant list. It is very easy to grow and requires very less effort in harvesting.