Foeniculum vulgare has long been utilized and cultivated by humans, and different forms have emerged through cultivation. This record is mainly referring to the wild fennel; see Foeniculum vulgare cv group Florence Fennel (syn Foeniculum vulgare azoricum (Mill.) P.Fourn.) for those forms developed to have edible swollen leaf bases; and see Foeniculum vulgare cv group Sweet Fennel (syn Foeniculum vulgare var. dulce (Mill.) Batt. & Trab.) for cultivars grown for their sweeter tasting seeds.

Common Name: Fennel

General Information

Foeniculum vulgare is a much-branched, erect, biennial to short-lived perennial plant growing from a taproot; it can grow around 100 - 300cm tall[].
The plant has a long history of cultivation, especially for use as a food and a medicine, and has long been cultivated for these purposes. It is also harvested from the wild for local use as a food, medicine and source of materials.
Foeniculum vulgare is a common kitchen herb used around the world - but it is also a highly invasive weed that can severely damage ecosystems. It is known to be invasive (mostly in natural habitats rather than agricultural land) in California, New Zealand, significant parts of Australia and a number of locations in the Pacific. The plant is known to alter fire regimes and create dense stands, outcompeting native flora for nutrients and space. It was listed in the Global Compendium of Weeds as an “agricultural weed, casual alien, cultivation escape, environmental weed, garden thug, naturalised, noxious weed, weed”. It can regenerate by both seeds and roots, which often makes physical control methods ineffective and chemical control necessary once a population is established[].

Known Hazards

Skin contact with the sap or essential oil is said to cause photo-sensitivity and/or dermatitis in some people[, ]. Ingestion of the oil can cause vomiting, seizures and pulmonary oedema[].

Botanical References

,

Range

Throughout the Mediterranean and east to northeast Africa, Pakistan and the Himalayas

Habitat

Found most often in dry stony calcareous soils near the sea[, , ].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Perennial
Height	1.50 m
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

Foeniculum vulgare is a plant mainly of mediterranean and warm temperate climates. It is fairly cold-hardy, known to tolerate occasional temperatures falling as low as -25°c so long as conditions are fairly dry, though it does lose its top growth in such conditions. It grows best in regions where the mean annual rainfall is within the range 500 - 2,000mm, tolerating up to 4,000mm, and the mean annual temperature is within the range 6 - 12°c, tolerating up to 24°c[, ]. Plants are liable to die out over the winter if the soil is not well-drained or the weather is persistently cold and wet[].
Fennel is generally an easily grown plant, it succeeds in most soils but prefers a sunny dry position[, , , ]. It grows well in sandy soils[] and is drought tolerant once established[]. The plant thrives in non-acid, well-drained loams and tolerates a soil pH between 6.3 and 8.3[]. Plants often self-sow freely in the garden[]. Plants can be grown in quite coarse grass, which can be cut annually in the autumn[].
Initial development of seedlingz is slow, with a period of 8- 12 weeks from sowing to stem emergence. Flowering occurs 3 - 4 months after sowing, and the time from sowing to first seed harvest is 5 - 7 months[].
Fennel is often grown as a herb and a vegetable, and is generally recognised as comprising three cultivar groups:-
cv. group Common Fennel (Foeniculum vulgare vulgare) This is the wild form of the species. Common fennel seeds have a pungent odour and taste rather like camphor with a bitter after-taste. This form is cultivated as a culinary and medicinal herb, and also for its seeds and essential oil.
cv. group Florence Fennel (Foeniculum vulgare azoricum). The basal portions of the leaf petioles are swollen to form an edible, bulb-like structure. This form is mainly grown for use as a vegetable.
cv. group Sweet Fennel. (Foeniculum vulgare dulce). Sweet-fennel fruits smell strongly of anise, and have a penetrating and sweet taste. The plant is generally grown as a culinary and medicinal herb, and also for its sweeter-tasting seeds and essential oil.
Especially in mild winters, the leaves can be available all year round[]. It is best to cut a few plants back to ground level occasionally during the growing season, thus ensuring a constant supply of fresh young shoots[]. In a dry summer make sure that you water the cut-down clump or it might not regrow that year[]. Fennel is also grown commercially as a medicinal plant and for its essential oil[, ].
It is best not to grow fennel and dill (Anethum graveolens) close to each other since hybridisation can occur and the resulting seedlings will be of indeterminate flavour[].

Edible Uses

Leaves - raw or cooked[, , , , ]. A delicious aniseed flavour[], the young leaves are best since older ones soon become tough[]. They are often used as a garnish on raw or cooked dishes and make a very pleasant addition to salads[]. They help to improve digestion and so are particularly useful with oily foods[]. The leaves are difficult to store dried[], though this does not really matter since they can often be harvested all year round, especially if the plants are in a warm, sheltered position[].

Leaf stalks and flower heads - raw or cooked[, , , ]. A similar aniseed flavour to the leaves[].

The aromatic seeds are used as a flavouring in cakes, bread, stuffings etc[, , , , , ]. They have a similar flavour to the leaves[] and also improve the digestion[]. The seeds have a pungent odour and taste like camphor[]. The sprouted seeds can be added to salads[].

An essential oil from the fully ripened and dried seed is used as a food flavouring in similar ways to the whole seed[, , , ]. The main component of the oil from wild fennel is fenchone, which gives the seed its bitter flavour, although it does also contain some (E)-anethole, which adds a sweeter, anise-like flavour[].

Root - cooked[]. Somewhat parsnip-like.

The leaves or the seeds can be used to make a pleasant-tasting herbal tea[, ].

Medicinal

Fennel has a long history of herbal use and is a commonly used household remedy, being useful in the treatment of a variety of complaints, especially those of the digestive system[]. The seeds, leaves and roots can be used, but the seeds are most active medicinally and are the part normally used[]
An essential oil is often extracted from the fully ripened and dried seed for medicinal use, though it should not be given to pregnant women[, ].

The plant is analgesic, anti-inflammatory, antispasmodic, aromatic, carminative, diuretic, emmenagogue, expectorant, galactogogue, hallucinogenic, laxative, stimulant and stomachic[, , , , , , , , ]. An infusion is used in the treatment of indigestion, abdominal distension, stomach pains etc[]. It helps in the treatment of kidney stones and, when combined with a urinary disinfectant like Arctostaphylos uva-ursi, makes an effective treatment for cystitis[].
The plant can also be used as a gargle for sore throats and as an eyewash for sore eyes and conjunctivitis[]. Fennel is often added to purgatives in order to allay their tendency to cause gripe, and also to improve the flavour[].

An infusion of the seeds is a safe and effective cure for wind in babies[].

An infusion of the root is used to treat urinary disorders[].

An essential oil obtained from the seed is used in aromatherapy. Its keyword is 'Normalising'[]. The essential oil is bactericidal, carminative and stimulant[]. Some caution is advised, see notes above on toxicity[].

The fatty oil obtained from the seed has antimicrobial properties[].

Agroforestry Uses:

Fennel is in general a poor companion plant in the garden. It inhibits the growth of nearby plants, especially beans, tomatoes and kohl rabi[, ]. It is itself inhibited by wormwood and coriander[, ]. However, the flowering plant attracts beneficial insects such as bees, parasitic wasps, tachinid flies and hoverflies to the garden. The presence of these creatures will help to maintain a natural balance of insects in the garden and help prevent infestations by aphis etc[].

Other Uses

The seed yields up to 5% of an essential oil[, , ]. This is used medicinally, as a food flavouring, in toothpastes, soaps, perfumery, air fresheners etc[, , ]. The flavour of fennel oil depends upon its two main constituents. 'Fenchone' is a bitter tasting element whilst 'anethole' has a sweet anise-like flavour[]. The proportions of these two ingredients varies according to strain and region. Plants growing in the Mediterranean and southern Europe usually have a sweet oil whilst plants growing in central and northern Europe usually produce a more bitter oil[]. The quality of the oil also depends upon how well the seed has been dried - the oil from fully ripened and dried seeds being much sweeter and more fragrant[].

The seeds of fennel contain approximately 20% fatty oil, of which about 80% is petroselinic acid[]. This acid is of interest because of its antimicrobial activity and because its oxidation gives Lauric acid (C12:0), a very important fatty acid used in the soap, cosmetic, medical and perfume industries[].

The dried plant is an insect repellent[, ], the crushed leaves are effective for keeping dogs free of fleas[]. The plant was formerly used as a strewing herb[].

Yellow and brown dyes are obtained from the flowers and leaves combined[].

Propagation

Seed - best sown in early spring in situ[]. Seeds normally germinate within 2 - 3 weeks after sowing[]. The seed can also be sown in situ in the autumn[, ]. In many gardens it self sows freely.
Division in early spring as the new growth appears[, ]. The plants are very tolerant of disturbance, we have found divisions to take well at any time of the year, though these divisions are never as good as seed-sown plants[].