Leaf Fennel, Bronze and Green (Foeniculum vulgare)

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Leaf Fennel, Bronze and Green (Foeniculum vulgare)

Common Names 

Sweet Fennel, Wild Fennel, Copper Fennel


About This Plant


Bronze Fennel and Green Leaf Fennel, commonly known as Sweet Fennel, are the wild cousins of the more commonly known garden variety bulb Fennel known as Florence Fennel or Finocchio.  They differ from Florence Fennel in several ways. While the bulb variety is typically grown as an annual and a “vegetable”, Bronze Fennel and Green Leaf Fennel are grown as perennials and are commonly referred to as “herbs” since they lack the enlarged, flattened stem bases that form the bulbous vegetable of Florence Fennel. 


Wild Fennel is a hardy herbaceous perennial in USDA Zones 5-11. In the lower zones, it can be grown as an annual.  It is a member of the Apiaceae family and both the foliage and seeds are edible. The foliage grows in airy “mounds” that reach of height of two to four feet or more, and breadth almost as large, depending on its growing location and soil conditions. It can grow quite large within a single year. Its foliage is feathery and thin, forming mounds of light, lacy, fern-like leaves that look similar to Dill. Its foliage is dense enough however that when grown in masses can form a solid background.  It can be grown in large containers, but typically does better in the ground because of its deep root. 


The young foliage of Bronze Fennel is purplish-bronze and fades to a dark green as it ages.  Its color can also be described as a deep brownish-gold. The foliage grows on stout stems. It looks fabulous when placed next to silver-leaved plants, such as sages or lamb’s ears. Its feathery foliage hangs like smoke around plants in the garden. It helps to fill in spaces and it makes a great back border in cottage gardens.  


In mid to late summer, Wild Fennel puts up a long stalk that can reach about four feet high. At the top of the smooth, hollow stalk, delicate umbels open with tiny yellow flowers. Each umbel section has 20-50 flowers on short pedicels and is loved by beneficial insects. WIld Fennel often doesn’t bloom until its second year, but dry weather may promote bolting in first-year plants. The flowers will turn brown and produce seeds.  The stalks can be cut back to the ground, prior to seeding, however, to keep the plants looking better longer. The plant will readily reseed in milder climates, naturalize, and can become invasive. In cooler climates, this is rarely an issue. Fennel has a long, white taproot that dislikes being disturbed. 


Wild Fennel has a sweet anise flavor. It is strongly scented and oftentimes can be smelled wafting over the garden.  Fennel, Anise, and Star Anise all contain the aromatic compound, anethole, which gives them their similar taste and aroma.


Fennel is an important host plant for the Anise Swallowtail and the Eastern Black Swallowtail. The butterflies lay their eggs on the plant and the larvae munch on it until they are ready to pupate. Deer will not eat Fennel.  Moles and Voles will eat the roots, especially over the Winter, so take any necessary precautions if these animals are in your area. Fennel has few pest problems but can suffer root rot in very wet soils. It will cross-pollinate with Dill which creates an undesirable flavor in the seeds. 


Wild Fennel was brought to the Americas by Spanish explorers in the 1600s.  They distributed it along El Camino Real or The Kings Highway that connects the 21 missions that span from San Diego to San Francisco, California. Today, the tall wispy foliage can be seen along Interstate 101 which follows the historical route.  The plant has naturalized to such a degree in the area that many consider it a native Californian plant.  Others consider it a weed. 


Fennel was believed to convey longevity and to give strength and courage in ancient times. Pliny the Elder documented over 22 ailments believed to be aided by Fennel. He believed it to be beneficial for the eyes after observing serpents rubbing their eyes against the plant while casting off their old skins. In the 14th Century, Fennel seeds were nibbled on as a snack to stave off hunger on religious fasting days. In medieval times, it was used along with other herbs as a preventative of witchcraft and evil forces.  It was hung over doors on Midsummer’s Eve to ward off evil spirits.  Fennel was also one of the three herbs used in making absinthe. 


Fennel is known to deter fleas. It can be planted near kennels and dried fennel can be spread inside of kennels to repel the pests.


Contact with the plant juices followed by exposure to the sun can cause skin irritation in some people. 




Fennel is easy to propagate by seed.  Seeds can be directly sown ¼” deep in the garden in Spring or Fall.  They can also be started indoors and planted outside as soon as the danger of frost has passed. Soaking seeds for 4 to 5 days prior to planting can help facilitate germination. Germination takes one to two weeks. Propagation by division is difficult because of the long taproot but is best done in the Fall. Wild Fennel reaches maturity in 60 to 70 days. 




When transplanting Fennel, take great care to remove all of the root and water very well for several weeks after moving.  The smaller the plant, the easier it is to transplant. Allow several feet between plants grown as perennials as they do spread over the years. 




Fennel grows best in full sun and well-drained soil.  These conditions are best for producing a plant rich in oils and seeds. Rich soil produces less flavor than poorer soil.  Fennel has low water requirements once established, but some water does produce bigger plants. Plants can be cut back to force them to become bushier.  If large plants get too leggy, they may require staking. 


Wild Fennel dies back in Winter and sends up new shoots in early Spring.  The plant will tolerate a light frost.  Plants can be cut back to the ground at the end of the season after the seeds have formed.  It is a plant that reseeds easily and can become invasive.  


Fennel is allelopathic to most garden plants, meaning many plants grow poorly when sharing spaces with Fennel, especially Beans and Tomatoes.  Fennel can inhibit the growth of other plants and cause them to bolt.  Fennel should not be planted near Carrots, Coriander, or Dill as they may cross-pollinate.


Seed Harvest


If you would like to harvest the seeds of Fennel plants, leave the flowering stalk intact and allow the plant to flower. You can still harvest the outer leaves for use. Seeds appear after a few weeks, normally around the end of August. Seeds are dark green to brown in color, are elongated, and ridged or grooved along its length. Seed heads should be cut as they turn from green to brown and allowed to finish ripening inside for the best flavor. Brown paper bags can be tied around the seed heads or they can be placed on screens to complete drying. Once mature, the seeds will easily shake loose from the main head. Store the seeds in a dry, airtight jar out of light. Seeds will keep for two to three years. The seeds turn grey as they age. 


Plant Uses


  • Culinary
  • Medicinal
  • Flower arrangements 
  • Butterfly Garden
  • Flea repellant


Culinary Uses


Versatile Fennel works well in both sweet and savory culinary creations.  Both the leaves and seeds are edible.  Fennel leaves make for a nice snack, just picked and chewed while walking around the garden.  It is easily harvested – just snip off what you need for cooking. Cut from the outer parts of the plant to allow the inner portions to continue growing. Fresh Fennel tastes great in salads with its sweet Licorice flavor.  Both Green Leaf Fennel and Bronze Fennel taste comparable and can be used interchangeably in recipes. Fennel leaves are often used stuffed into the cavity of whole fish or used to wrap fillets.  They pair well with egg dishes. The soft wispy leaves, especially with the unique color of Bronze Fennel, add interesting visual texture to any dish. The leaves do not retain their flavor when dried


The seeds have a warm, sweetish, and aromatic odor and flavor.  Tea can be made from either the leaves or seeds. Try steeping milk with fennel and using it to make ice cream or add it to your baked goods.  Fennel seeds are used in the making of cordials and liqueurs. They are also used in sausage making, and in the making of pastries and confections.  Ground seeds are a key ingredient of Chinese five-spice powder and Indian garam masala.


Fennel contains vitamin C and folate, potassium and iron, and is a decent source of inflammation-fighting antioxidants.


Medicinal Uses


Fennel is a plant that has been used medicinally for centuries, most commonly for digestive problems. It is used to relieve flatulence and colic and stimulates digestion.  It historically has been used with purgatives to allay their griping tendencies. It has been a common component of “Grip Water” used to alleviate gas pains in infants. It is anti-spasmodic, and anti-inflammatory and can calm bronchial coughs. A syrup prepared from Fennel juice was given for chronic coughs


Fennel’s use dates back to ancient Egypt.  Hippocrates was a fan of Fennel’s medicinal benefits.  




Fennel is native to southern Europe along the Mediterranean Sea. 


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