Botanically known as Foeniculum vulgare dulce, Fennel is a flowering perennial plant that is a member of the Apiaceae (carrot) family. The plant bears yellow flowers and has feathery leaves. It grows to a height of about 5 feet. Indigenous to southern Europe, Fennel naturally carries a sweet aroma like Anise. Overview of Fennel Sweet Essential Oil A colorless or pale yellow oil is extracted from the dried green fennel seeds through steam distillation by fennel (sweet) essential oil manufacturers. Fennel Sweet Essential Oil is a powerful and effective oil known for its strong, sweet, licorice taste and fragrance.