Fennel (Foeniculum vulgare Mill.) Fennel is a tall, hardy, aromatic perennial of the parsley family. Other than most of their relatives, the seeds retain a green color after drying. As a rule of thumb, a bright green color indicates a good quality. The taste of fennel is sweet and aromatic, similar to anise. The name Fennel is derived from the Roman foeniculum, a variety of fragant hay.