By Dr. Mercola
Fennel is an herb with a mild but distinctive licorice flavor, popular in foods in Southern Europe and the Mediterranean region. Every part of the plant can be eaten, including the seeds once the plant has flowered. Part of the carrot family, the plant is a perennial.
Although classified as an herb, many chefs use the lower part of the plant, or the bulb, as a vegetable, adding it to salads, soups and stews. Although the bulb is layered, the stems of the plant are hollow. Fennel is cultivated in many parts of the world, but it also grows wild along roadsides and open pastures.
It propagates well each fall by seed and is considered an invasive species of weed in Australia.1
The fronds that grow on the top of the plant may also be used in salads or as a garnish, much like dill. Interestingly, it is one of the main herbs used in the preparation of absinthe, an alcoholic beverage referred to as "spirits," as no sugar is used in the distilling process.
The preparation of absinthe was invented by a physician who distilled herbs into an alcoholic base as a remedy for his patients, with the intention of delivering healing properties of the wormwood plant in an easily ingestible form.2
However, it is often greater than 45 percent alcohol, defeating any health benefits from the herbs used in the creation of the product.
The History of Fennel
The first recorded use of fennel was by Roman author Pliny, who lived between 23 A.D. and 79 A.D. He wrote that snakes rubbed their faces against the plant while shedding their skin.3 Believing there was power in fennel, he used it to treat 22 different complaints.
In 812 A.D., Charlemagne decreed it should be grown in every garden to take advantage of its healing properties.4 By the 1300s the herb was a staple in the home of King Edward I of England, who would order up to 8.5 pounds of fennel seed each month.
At that time, fennel seed was used as an appetite suppressant and a condiment. The Greek name is "marathon," or to "grow thin," in reference to its reputation for weight loss.5
Fennel was often hung over doorways or inserted into keyholes to ward off evil spirits from the home. Even poet Henry Wadsworth Longfellow (1807-1882) found reason to write about fennel in his poem "The Goblet of Life," writing:6
Above the lowly plants it towers,
The fennel, with its yellow flowers,
And in an earlier age than ours
Was gifted with the wondrous powers,
Lost vision to restore.
Modern therapeutic uses began in Germany and the U.S., founded on traditional medicine practiced by ancient Greek physician Hippocrates, generally regarded as the father of medicine.7
Fennel has been integrated into many other systems of medicine, including traditional Chinese medicine and Ayurvedic pharmacopoeia. In the mid-1600s it became popular in the preparation of fish and was also used as an antidote to poisonings, snake bites and the bites of "mad dogs."8
Prepare to Plant for a Summer of Fresh Fennel
With centuries of medicinal practices using fennel, a strong nutrient profile and a powerhouse of flavor, it may be time to grow fennel in your own backyard. Growing your own plants gives you greater control over plant health and chemical use, and you're able to harvest and eat within the same day.
Fennel seeds are most viable when fresh, but some have germinated when they are 4 years old. The seeds can be started indoors or planted directly outdoors.
However, as the plant may be invasive and will seed the surrounding area, it may be prudent to plant where there are natural borders or in a pot. Plants may also cross-pollinate, so you want to keep your fennel to the back of the garden.9
In warmer climates, it is possible to sow seeds in the early fall to reap an early spring harvest.10 The plants need full sun exposure and well-draining soil. As you choose where to plant your fennel, remember it grows between 5 and 6 feet tall, with a core like celery and a base shaped like an onion.11
As with all plants, the soil you start with will be a large factor in determining the health of your harvest. If you're planting in a pot, it's easier to control the soil and organic material you use. Choose an area of your yard where you can add organic fertilizer and a place that drains well.
This protects your plants from disease and pests that flourish on weakened plants. Container gardening has several other advantages, not the least of which is being able to grow a garden on an apartment balcony or your back porch.
You can move the containers as the needs of the plants change through the season, and you can separate plants if they become diseased while you're treating them so the disease doesn't spread.
Growing and Harvesting Your Fennel Plants
One of the more important factors in growing fennel is well draining soil. Well-fertilized soil may reduce the taste and aromatic oils of the plant. After sowing seeds 12 inches apart in the ground or 3- to 5-gallon pot, cover with a quarter inch of soil and water daily with a light spray nozzle until the shoots appear.12
Once shoots are up, you may water once or twice weekly if they are in the ground and possibly more frequently if the soil in your pots dries quickly.
As the plants grow, they may need staking after they reach 18 inches, especially if they are planted in a windy location. The plants are very hardy and may even continue to grow in mild winters.
If you don't want to harvest seed, or want the plant to reseed, it's best to cut the flowers from the plants as soon as they appear. How you can harvest seed is discussed below. To expand your crop you may cut some of the side roots from the long tap root and plant them separately for a new plant the following growing season.
Harvesting a bountiful crop of fennel doesn't require much work as the plants are hardy, resist disease and pests and often continue to grow in your garden after removing all visible signs of the plant and roots.
The leaves are best harvested just before the plant blooms. Fennel does appreciate weeding, especially around young plants as they become established. If your winter months are especially cold and reach below freezing, the plants will survive best if they have several layers of mulch covering them.
Fennel also doesn't play well with other herbs in your garden, another reason container gardening works well for this herb. Although some have planted dill close to fennel, it may cross pollinate and destroy the flavor of both plants.13
Fennel Seeds Pack a Powerful Punch of Flavor
Harvesting and drying fennel seeds is a process that requires some care as the seeds easily fall to the ground and quickly seed the area with new growth. The seeds should be harvested as they turn from green to brown on the stalk of the plant.14
If you wait too long, the seeds will drop from the plant and, spread by the wind, seed your garden and lawn. Carefully cut the seed head, or umbrel, off the plant without losing seed. You may also bend the plant over white muslin to catch any seed that breaks free of the plant as you are cutting.
Place the seed head in a paper bag and give it a few good shakes to free the seeds. Or, you may have to let the seed heads dry in a paper bag for a few days to a week so the seeds easily come free.15
The seeds should be dried before eating, on a screen in a well−ventilated area, for a couple of days. Store them in a dark container in a cool, dark place to ensure they retain their flavor.
Treat Pests Naturally
By eliminating the use of chemicals to keep your plants healthy, you ensure you're eating healthy, chemical-free plants. The fennel plant has a few natural enemies, and those enemies have natural predators.
Aphids and armyworms are the two most common pests that attack a fennel plant.16 If aphids are limited to one or two branches of the plant, they can easily be pruned. Older, sturdy plants can be sprayed with a strong jet of water that will knock the insects off the plant.
The armyworm is a destructive pest best kept under control by natural predators. Green lacewing insects, lady bugs and dragon flies are natural predators for aphids17 and armyworms.18,19 You can attract them to your garden or populate the garden by purchasing them at a local gardening store. Fennel naturally attracts the lacewing and lady bug. You may attract dragonflies by planting a variety of blooming plants, such as the Black-Eyed Susan.
Health Benefits Make Fennel a Great Choice for Your Kitchen and Garden
Although the taste and scent may remind you of anise or licorice, the plant is actually related to caraway.20 Its aromatic scent may help repel fleas from your dog. An old gardening expression suggests planting "a fennel near your kennel" to protect your dog from fleas.21
Crunchy and sweet, fennel is often associated with Italian and Mediterranean meals. Like most spices, it has a unique combination of phytonutrients with potent antioxidant activity. The primary component of the volatile fennel oil is anethole, shown to reduce inflammation and prevent cancer.22 Researchers propose the anti-cancer properties are related to shutting down tumor necrosis factor mediated signaling.
The fennel bulb is also a good source of vitamin C, potassium, folate and fiber.23 Your body utilizes vitamin C as a cofactor in numerous enzymatic reactions and in the production of collagen, important to your skin, tendons and ligaments. Studies have demonstrated a higher intake of vitamin C is associated with a reduced risk of heart disease and stroke.24
Potassium is an essential mineral and electrolyte your body uses to prevent disease, regulate your heart beat and muscle activity, and regulate bone cell generation. It also may help lower high blood pressure.25 Folate is a water-soluble vitamin used in the metabolism of several amino acids and is critical to the production of nucleic acid.26 Low folate levels may increase your risk of cardiovascular disease and cancer, and may result in birth defects.
Fiber is essential to maintaining a healthy gut microbiome and gastrointestinal health. Poor gut health may lead to increased allergies, cardiovascular disease, inflammatory response and cancer, and may affect your mental and emotional health as well.
Fennel may also help counteract postmenopausal bone loss.27 In a study evaluating osteoclast differentiation and bone resorption in postmenopausal women, researchers found that fennel decreases bone turnover markers and offers a protective effect in preventing bone loss.
Fantastic Fennel Oil
The oil comes from crushing the fennel seeds and has been used in cosmetics, soaps, massage oils and perfumes. The chemicals found in the oil include anethole, estragole, fenchone, β-pinene, and α-pinene.28 The oil acts as a stimulant and has been used to treat insect bites and as a form of aromatherapy.
While it is commercially available, you may also make your own sweet fennel oil infusion at home to preserve the flavor of the herb for use in a variety of dishes and marinades. This recipe for making your own oil is from Preserving Your Harvest:29
- Salad Spinner or clean kitchen towels
- Medium bowl
- Wooden spoon
- Large wide mouth jar
- Good quality extra virgin olive oil
- Fresh fennel sprigs
- 1/4 or 1/2 dry measuring cups
- 2 cup liquid measuring cup
- Cheese cloth
- 1/4 to 1/2 cup of fennel leaves
- 2 cups of extra virgin olive oil
- Pick the freshest herbs, wash and gently spin dry or blot between two kitchen towels to remove as much moisture as possible.
- Place the fennel leaves in the bowl and crush slightly with the back of the wooden spoon to release plant flavors.
- Pour half (1 cup) of the oil over the bruised leaves.
- Stir and crush again slightly to release more of the plant oils.
- Add remaining cup of oil and stir well to blend.
- Pour into the large mouth jar and cap tightly.
- Set on a sunny window sill for two weeks, shaking gently every day or so to mix the flavors.
- Strain oil slowly through a double layer of cheese cloth set into a large funnel in the opening of a clean decorative bottle and cap tightly.
- Add a few fresh sprigs of fennel for decoration and identification purposes and label.
How to Store
After the seeping process, keep the flavored oils out of direct sunlight in a kitchen cupboard or pantry. Oils tend to go rancid if left in the sun too long. The shelf life of flavored oils is approximately six months.
Tasty Ways of Using Fennel in Your Kitchen
The fennel plant may be used in several different ways, from seeds in your salad, to sautéed sliced bulb on a sandwich. The video above shows you how to prepare and slice the fennel plant. The original recipe for this Indian spice-inspired fennel and carrot side dish can be found on AllRecipes.com.30
- 1 teaspoon high quality olive oil
- 3 carrots, shredded
- 1 fennel bulb, trimmed and diced
- 1/2 teaspoon ground coriander
- 1/4 teaspoon fennel seeds
- 1/3 cup heavy cream
- Heat the olive oil in a skillet over medium heat.
- Stir in the carrots and fennel, and season with coriander and fennel seeds.
- Cook until lightly browned. Mix in the heavy cream, and reduce heat to low.
- Simmer about five minutes until the cream has been absorbed into the carrots and fennel.
- Serve hot.