Plant Common Sweet Fennel (Foeniculum vulgare) for Swallowtails!

Sweet Fennel (Foeniculum vulgare) is also called Common Fennel and Sweet Anise. It’s a common herb and a weed, like its cousin dill, but boy, does it attract butterflies! Especially Black and Anise Swallowtails, who crave the aromatic blooms and lay their eggs on the leaves. Their caterpillars are commonly called parsley worms because they’re most often found on parsley, carrot, dill and other members of the carrot family.

Fennel has a long history of medicinal use by Asian, African, and European cultures. It’s even associated with the origin of marathon races. The battle of Marathon, between Sparta and Persia, is said to have been waged on a field of fennel, and the soldier who ran for 2 days to get Spartan reinforcements carried a fennel stalk on his journey, for endurance.

Characteristics Of Sweet Fennel Plants

Sweet Fennel has traditionally been grown for its licorice-flavored seeds, but every part of the plant, including its flowers, is edible. There are two general varieties of fennel, herb (Foeniculum vulgare), which is our butterfly plant, and bulb (Florence fennel or Finocchio – Foeniculum vulgare var. dulce), which is grown as a vegetable.

Sweet Fennel is native to the Mediterranean, and so does best when it reaches maturity in cool weather. It’s perennial in zones 4-9. It prefers moist, well-drained soil and plenty of full sunlight. Foeniculum vulgare grows up to six feet tall in ideal conditions; in windy areas, its hollow stems may require staking.

Foeniculum vulgare flowers in July and August, sporting pretty clusters of aromatic, flat-topped, golden-yellow blossoms. A month or two later, the flowers turn to seed.

How To Start Sweet Fennel Seeds

Since Sweet Fennel is half-hardy, and tolerates light frost, you can sow in spring, 2- 3 weeks before the last frost, or in early fall, before the first frost.

Direct plant seeds into wet soil about 10 seeds per foot, or several in a bunch a foot apart. Sweet Fennel seeds need darkness to germinate, so cover them with ¼” of dirt. Seedlings will appear in about 7-10 days. Thin successful seedlings 10-12″ inches apart. If planting in rows, space them 2-3′ apart. Fennel re-seeds itself readily.

Give Foeniculum vulgare consistent water until it is established. After that, it can be kept on the dry side.

Sweet Fennel can provide you with more than butterflies and other pollinators! Harvest its seeds in the fall and bake them into breads, biscuits, and stuffing, or use them to flavor sausages and pickles, or as a dressing for raw vegetable salads.

Order a true multi-use flowering herb and attract and grow Swallowtail butterflies, too!