Fennel plants (Foeniculum vulgare) are aromatic annuals or perennials with feathery, finely divided aromatic leaves and large, flat umbels of tiny golden yellow flowers borne on tall hollow stems. Blooming in summer, the flowers attract butterflies and give way to aromatic seeds. Fennel is also valuable for its masses of fringed foliage that attract birds and its delicious bulbs.

Two forms of Fennel are commonly grown.

Some varieties of Fennel have a particular sweetness and some ornamental qualities, while others are eaten as a vegetable.

• Herb Fennel: Also called Sweet Fennel, it is a long-lived aromatic perennial mainly cultivated for its seeds. Often mistaken for dill, it is a stunning ornamental plant, providing height and graceful airiness to the border. It is used as an herb for food flavoring. All parts of the plant (foliage, seeds) are anise-scented and have a long history of cultivation for culinary purposes. Fennel seeds are baked into bread, biscuits, or Italian sausages. Stems can be grilled with fish, meats, and vegetables, and leaves can be added to salads or used as a garnish.
   
• Vegetable Fennel: Foeniculum vulgare var. azoricum (Florence Fennel or Finocchio) is grown as an annual for its edible leaves and leaf bases. The plant boasts swollen leaf bases, which form a bulb-like structure that is consumed as a vegetable. Florence Fennel has a delicious, licorice-like flavor. The succulent bulbs are used cooked or raw. The feathery leaves are used as a garnish and seasoning. Florence Fennel is one of the primary ingredients of absinthe.

Fennel Health Benefits

• While Fennel makes a flavorful addition to salads and various dishes, it can also provide some health benefits.
• Fennel is low in calories but highly nutritious. It is rich in iron, vitamin A, vitamin C, calcium, magnesium, potassium, and manganese.
• Fennel improves digestion and relieves gassiness.
• Fennel may help maintain a healthy heart thanks to heart-friendly nutrients like potassium and folate.
• Rich in antioxidant nutrients such as vitamin C and plant flavonoids such as quercetin, Fennel may help reduce inflammation.
• Although eating Fennel and its seeds is likely safe, consuming higher doses in supplement form may react with certain medications and is unsafe for pregnant women.

Growing Fennel

• Grows vigorously up to 4-6 ft. high (120-180 cm) and 1-3 ft. wide (30-90 cm).
• Prefers rich, moist but well-drained soils in full sun.
• Herb fennel is drought tolerant once established and requires little maintenance apart from removing dead stems at the end of the growing season. 
• Florence fennel needs plenty of moisture consistently throughout the growing season. Mulch with garden compost to retain moisture.
• Fennel attracts butterflies, birds, and beneficial insects but is deer resistant.
• Easy to grow, Fennel is a welcomed addition to beds and borders, cottage gardens, and wildlife gardens.
• Both herb fennel and vegetable fennel are grown from seeds.
• The best time to sow herb fennel seeds is in spring when the danger of frost has passed.
• The best time to sow seeds for vegetable fennel is in late spring to mid-summer.
• Fennel dislikes having its roots disturbed or being transplanted. 
• Feed Florence fennel with a high-potassium fertilizer every two weeks once established.
• Earth up (mound soil) around the bulbs as they start to swell to blanch them and protect them from early autumn frosts.
• Harvest foliage and flowers as required. Harvest seeds when ripe, then dry and freeze them for a few days to kill insects.
• Harvest Florence fennel bulbs when they reach the size of a tennis ball.
• No serious pest or disease issues. Watch for aphids. Stem and root rot may occur in poorly-drained soils.
• Fennel is a natural flea repellent: rub a handful of fresh fronds all over your dog or cat.
• Native to the Mediterranean region, Foeniculum vulgare has escaped gardens and naturalized in many parts of North America.
• Fennel can be invasive if flowers are allowed to set seed. Remove spent flowering stems before the seed is produced to avoid undesired self-seeding.
• Find where Foeniculum vulgare species is invasive in the United States.
• Discover beautiful U.S. native plant alternatives.
• Contact with plant juices and exposure to the sun can cause skin irritation.

Fennel: Companion Planting

• Fennel is one of the few plants that has mostly bad companions. Most plants dislike Fennel, and it should be planted well away from the vegetable garden.
• Fennel inhibits the growth of any nearby plant, including kohlrabi, bush beans, eggplant, caraway, and tomatoes.
• Fennel is inhibited by the presence of coriander and will not form seed.
• Fennel also dislikes wormwood.