Gardening Herbs

Fun Facts About Fennel

Tall fennel plant in bloom.
Fennel (Foeniculum vulgare) is a tall perennial herb with many uses. Photo: Alvesgaspar, Wikimedia Commons.

Fennel is a deliciously scented and tasty herb with much to offer the home gardener. But that was a pretty succinct description for a plant with multiple attractions and uses. Here are some fun facts about fennel that will certainly surprise you!

  1. Fennel (Foeniculum vulgare) is a perennial herb native to the Mediterranean region.
  1. It belongs to the Apiaceae family (umbellifers) and is closely related to anise (Pimpinella anisum) and dill (Anethum graveolens), two annual herbs.
  1. What does fennel taste like? Well, different parts have somewhat different tastes, but many people say it tastes (and smells!) a lot like black licorice!
  1. The wild form of fennel can be very tall (up to 8 feet/240 cm in height). However, cultivated varieties are shorter: rarely much more than 5 feet (150 cm), even 2 feet (60 cm) in the case of Florence fennel.
Soft, feathery leaves of fennel.
The fine, threadlike leaves give the plant a soft, feathery appearance. Photo: David Stang, Wikimedia Commons
  1. The compound leaves are extremely fine and feathery, almost like threads, born on petioles that wrap around the pith-filled stem.
  1. The name “fennel” can be traced back to the Latin word Latin faeniculum, a diminutive of faenum, meaning “hay,” because of the haylike appearance of its dried leaves.
Prometheus returning fire to humans
Prometheus returning fire to humans. Ill.:
  1. Fennel features prominently in Greek legends.

    One legend recounts that the father of the gods, Zeus, was dissatisfied with humans and wanted to replace them with superior beings. So, he took fire away from them and kept it out of their reach at Mount Olympus. Without fire, they would no longer be able to cook meals and feed themselves.

    Seeing their distress, a kindhearted Titan named Prometheus snuck into Zeus’s throne room and stole a seed of fire, slipping it inside a hollow stalk of fennel. Its stem has the capacity of being fresh, green and moist on the outside, yet dry and hollow inside, once the pith is removed. So, rather than burning, the fennel hid the fire seed from view.

    Since handling a simple stalk of fennel aroused no suspicions, Prometheus was able to sneak fire out of Mount Olympus and return it to humans.

    To this day, a fennel stalk is still used in the Greek islands for carrying light. 
  1. The Greeks call fennel marathon. It is said to have grown wild on the first fields where marathon races took place.

Unraveling Fennel Names

Did you know there is more than one kind of fennel?

Here are the differences between the main categories.

Common Fennel (F. vulgare vulgare)

This is the traditional cultivated fennel, a tall plant not much different from the wild form, except for its sweeter seeds. It is mostly used in its original Mediterranean region (Greece, Italy, etc.) USDA hardiness zones 5 to 10.

Bitter Fennel (Foeniculum vulgare piperitum)

Also called wild pepper fennel and bitter finocchio. This is close to wild fennel, with an intensely bitter flavor and can become very tall. It is mostly used medicinally. Chefs do use it in cooking, but generally in specific regional recipes from Greece and Italy. USDA hardiness zones 5 to 10.

Sweet Fennel (F. vulgare vulgare dulce)

Sweet fennel showing stem with no bulb at the base.
Sweet fennel is the main herbal fennel. It’s a tall plant with no bulb at the base. Photo: Karelj, Wikimedia Commons

This fennel, also called Roman fennel, it one gardeners grow as a herb. All parts are edible and commonly used, but probably its thin, threadlike leaves, grown mostly as a cooking and medicinal herb, most of all. They have a wonderful light anise flavor. The hollow stalk is also edible, but coarser. It’s used as much as you would celery. Its seeds are edible, too … but so are the seeds of all fennels. They’re often used both as an aromate and flavoring and medicinally. It’s tall (4 to 5 feet/120 to 150 cm or so), leafy and solidly perennial (plants can live for a 6 years or more). It’s also quite hardy (USDA hardiness zones 5 to 9).

Florence Fennel (F. vulgare vulgare azoricum)

Florence fennel with a white bulbous baise.
Florence fennel (Foeniculum vulgare vulgare azoricum). Photo: Arnaud, Wikimedia Commons

Also called bulb fennel or finocchio. In spite of its name, Florence fennel is not native to Florence, but possibly the Azores where wild plants have a similar appearance and the same biennial nature.

It’s a much shorter plant (about 2 feet/60 cm) with an edible “bulb” composed of overlapping leaf bases. The bulb is the part people usually harvest and use as a vegetable. Try it raw or cooked. You can also use the other parts—leaves, stalk, flowers and seeds—, but mostly as herbs (flavoring, garnish, teas, etc.).

Unlike other fennels, this variety is a biennial: grown on its own, it produces leaves the first year, then flowers and seeds the next before dying the second fall. However, most gardeners grow it as an annual. They generally harvest it at the end of the first summer when the bulb is at its biggest.

Florence fennel is also the least hardy of the fennels: USDA zones 7 to 10. It will not overwinter in colder climates.

  1. Fennel has a wide range of medicinal uses dating back beyond the dawn of history. Ancient Greeks and Romans used fennel for medicine and insect repellent, for example. Ancient Egyptians used it medicinally, but also as food. Its use spread to Asia and Africa, all long before modern times. In China, it was used to treat snake bite. During medieval times, Europeans used to hang it from doorways to keep out evil spirits.
  1. In 812 CE, Emperor Charlemagne required the cultivation of fennel on all imperial farms and monastery gardens so everyone could profit from its therapeutic properties.
  1. Today, fennel oil helps cure nausea, vomiting, and seizures. It is known to be an antioxidant, antimicrobial, antispasmodic, and to stimulate gastrointestinal motility.
  1. Among the numerous other medicinal uses for fennel, you can chew fennel seeds to stave off hunger, notably during Lent. And it can help reduce weight gain.
Umbel of yellow fennel flowers.
Fennel flowers are edible and used as garnish and in flower arrangements. Photo: Fir0002, Wikimedia Commons
  1. You can use fennel in the kitchen in many ways:

Seeds: In breads, biscuits, Italian sausages, sauerkraut, tea, and much more.

Stems: Grilled with meats, fish and vegetables. They add crunch to salads.

Leaves: Add to salads, pickles, olives, fish, teas and use as garnish.

Bulb: Use as a vegetable, raw or cooked. Many recipes are available.

Flowers: Attractive in arrangements. Also edible and used as a garnish.

Giant fennel plant.
Giant fennel (Ferula communis) is not a true fennel. Photo: Krzysztof Ziarnek, Kenraiz, Wikimedia Commons
  1. Giant fennel (Ferula communis) is not a true fennel: This is a different species from a different genus (Ferula rather than Foeniculum), although it does look like a huge fennel plant. (It can reach 15 feet/4.5 m tall!) It’s a coarse thug of plant with a pungent, repulsive smell. It’s almost never grown in gardens and is not considered a culinary herb. It grows wild in the Mediterranean area. Other species of the genus Ferula, also called giant fennel, not are not used in cooking either.
  1. You can easily grow your own fennel from seed. Sow its seed directly into the ground in spring when the ground is warm, and thin plants to 12 to 18 inches (30 to 45 cm). Or start indoors it indoors 4 to 6 weeks before the last frost. Use peat pots, as the roots are fragile and should not be disturbed.
  1. You can also divide mature sweet fennel plants in the spring to produce more plants, but do so carefully, disturbing the roots as little as possible, as they can react badly to transplantation.
  1. People grow fennel all around the world and it has naturalized in northern Europe, Australia and North America. In areas where its invasiveness is a concern (it seems particularly invasive in areas with sparse vegetation or arid conditions), make sure to harvest the seed before it matures.
  1. The city of Funchal, the capital of Madeira, gets its name from the Portuguese name for the wild fennel that once grew there: funcho.
  1. Some gardeners prefer to blanch Florence fennel, hilling soil at its base as soon as the bulb is the size of an egg. This will give a whiter bulb with a milder taste. Unblanched bulbs are pale green.
Row of Florence fennel in a garden.
You can use Florence fennel, with its bulbous base, as a vegetable. Photo:, depositphotos
  1. You can harvest Florence fennel as a baby vegetable when the bulb is 3 inches (7.5 cm) in diameter or at maturity at 5 to 6 inches (12 to 15 cm) in diameter. To harvest, cut under the bulb to slice through the tap root. As for harvesting leaves and stems, you can do so at any time.
  1. Some people allergic to pollen, especially birch pollen, may be sensitive to a protein found in fennel. If you develop symptoms (itchy eyes, irritated throat, runny nose, sneezing, etc.), seek medical attention before symptoms become more severe.
Bronze fennel with purplish leaves.
Bronze fennel (F. vulgare vulgare ‘Rubrum’) is a popular ornamental variety. Photo:
  1. Fennel, with its extremely fine foliage and umbels of tiny yellow flowers, is an attractive plant and looks great in a flower bed or balcony container, not to mention a flower arrangment. Bronze fennel (F. vulgare vulgare ‘Rubrum’), with purple-green foliage, is indeed mostly grown as an ornamental.
  1. Don’t plant fennel near dill (Anethum graveolens) if you intend to save the seeds, as the two can cross, producing plants of lesser desirable flavor.
  1. Fennel makes a great larval host for the parsley worm, a colorful caterpillar that turns into an even more attractive butterfly, the black swallowtail (Papilio polyxenes). If you don’t want to share your fennel with a hungry herbivorous insect, just move the caterpillar to a wild carrot plant, an alternate host.

Hoverfly visiting fennel flowers.
Hoverfly visiting fennel flowers. Photo:
  1. Fennel flowers are very popular with a wide range of species of other butterflies, too, that come to feed on its nectar and pollen. And as do a whole host of other beneficial pollinators: bees, hoverflies, wasps, beetles, flies, etc. Some scientists find fennel so effective as a generalist source of nectar and pollen they call it a “magnet plant.”
Fennel essential oil, leaves, flowers and seeds.
Fennel essential oil. Photo: Madeleine Steinbach, depositphotos
  1. Essential oil from fennel seeds is a common additive to perfumes, soaps, pharmaceuticals and cosmetics, but is too strong for use in cooking. Even amounts as small as 1 ml can cause nausea, vomiting, seizures and other problems.
  1. Other than as seed or oil, fennel doesn’t store very well, nor can you freeze it. Expect a Florence fennel bulb to keep for up to a week in the refrigerator. To help it last as long as possible, cut off the stems and wrap the bulb in plastic wrap. As it becomes older, it becomes more fibrous and loses its flavor.
Florence fennel labeled as both anise and fennel.
This supplier has confused anise with fennel. However, this plant, with its bulbous base, is clearly Florence fennel Photo:
  1. Supermarkets often confuse fennel with anise. They are different plants, but are close relatives and do share a similar liquoricelike scent and taste. Here’s a hint. If your store offers a green plant with finely cut leaves and a white bulb, it’s fennel, not anise. Anise never has a bulb. They usually only sell anise in the form of seeds or ground seeds.
  1. You can use a fennel stem as a bio-straw. At maturity, the white pith in the stem’s center melts away, leaving it hollow. So, you only need to harvest a section of stem, plunge it into your favorite drink and suck in. It will impart a delicious light overtone of licorice to the drink… and causes no harm to the environment, as you can simply add the used straw to the compost, unlike plastic straws!
  1. Companion planting, popular in the 1970s and 1980s, held that fennel was a poor neighbor, harmful to just about any plant growing near it. The result is that many gardeners still ban fennel from their plantings. However, companion planting has been largely debunked over the last half century. And one proof of its ineffectiveness is that it turns out that fennel grows perfectly well with just about any vegetable or herb. Try it and see!

And there you go: 28 fun facts about fennel. Now you know so much more about this fascinating plant!

5 comments on “Fun Facts About Fennel

  1. Most interesting blog – thanks

  2. Ferne Dalton

    I have grown bronze fennel just once before. In my case it drew many wasps for a week or two. Fascinating. I sat with my camera and took close-ups. The wasps were all over it and ignored me even though I was quite close. Very pretty plant too. I will try to find some seed. I found this easy to grow.

  3. Thank you. We enjoy watching the various insects that come to our wild fennel. Also, when the seeds appear, we enjoy watching the nuthatches come and glean the seeds.

    When we were raising rabbits (son in 4H), I would give them a piece of fennel and they would “magically” make it disappear.

  4. Great article. Didn’t know about it being a larval host. Will have to check out my plants. Have never had much luck with regular fennel but Florence fennel is a breeze from seed.

  5. Excellent review. I grow fennel mainly as a larval host for swallowtail butterflies (and of course nesting birds need to feed a few of these caterpillars to their babies). plants do not mind growing beside it.

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