Fennel
Foeniculum vulgare
Botanical family: Apiaceae
A Mediterranean apiaceae (Foeniculum vulgare) with feathery aniseed foliage and yellow umbels rich in nectar. A distinction is made between bulb fennel (var. azoricum), grown in the vegetable garden for its fleshy 'bulb' harvested in autumn, and the aromatic common fennel, perennial, from which leaves and seeds are harvested. A host plant for the swallowtail caterpillar.
Full sun
Light, drained
Sparing for aromatic fennel; regular for bulb fennel (otherwise it bolts)
Common fennel, a perennial, is hardy in well-drained soil; bulb fennel is harvested in late summer and autumn, earthed up against the first frosts
Overwinters in your zone
Role in permaculture
Reputed to hinder its neighbours (effect shown mostly in the laboratory): grow it apart as a precaution. But very useful to pollinators, and a host plant of the swallowtail.
Poor companions
Allelopathy, reputed or observed: may slow some neighbours
Insects attracted or useful
Seasons & availability
Bulb fennel: harvested in summer and autumn.
Available: July, August, September, October, November.
Guidance for the oceanic / temperate climate; it may vary with your region, altitude, exposure and growing method.
Sources
- RHS, « How to Grow Florence fennel » (rhs.org.uk/vegetables/florence-fennel/grow-your-own)
- La Ferme de Sainte Marthe, « Réussir la culture du fenouil » (fermedesaintemarthe.com/en/blogs/comment-reussir-la-culture-de/reussir-la-culture-du-fenouil)
Nutritional & medicinal properties
For educational purposes. Not a substitute for medical advice. Effects depend on the form, the dose and personal context.
Precautions & contraindications
Fennel essential oil and concentrated extracts contain estragole, classed as a potential genotoxin by the EFSA (2009): to be avoided in infants, children, and pregnant or breastfeeding women. No more than a few cups of light infusion per day in prolonged use in adults.
In the kitchen & the apothecary
Where to find fennel in preparations: recipes and traditional herbal teas.
Infusions & herbal teas
Family behaviour: Apiaceae
In general, Apiaceae are umbel plants (carrot, parsley, celery, coriander, dill) whose flowers attract precious beneficials: hoverflies, ichneumons, parasitoids. Fairly easy to pair, except fennel, they are useful along edges to feed beneficials.
But this plant is an exception
Reputed to hinder its neighbours, against the grain of its family, the Apiaceae: in the laboratory its essential oil slows the germination of two weeds (Gharibvandi et al., 2022). Best planted apart as a precaution.
Understanding families means learning one rule per family rather than every pairing one by one. Learn more →
Species & varieties
The best-known species and varieties in France.
Common varieties
Voices of peoples
Paraphrases attributed to their documented sources. Never an invented quote.
Ancient Greece, a place name attested as early as Mycenaean (Linear B) · Attica (plain of Marathon)
The name of the site of Marathon derives from the Greek μάραθον (márathon), 'fennel'. The place is said to have been so named because wild fennel grew there in abundance; the coastal plain near the marshes suited it. The word is old: it is already attested on the Mycenaean tablets in Linear B (form ma-ra-tu-wo), well before classical Greek.
Chantraine/Beekes, Etymological Dictionary of Greek, s.v. μάραθον (relayé par Wiktionary et etymonline.com, s.v. « marathon », consultés le 2026-07-17)
Here the identification is solid: μάραθον does designate fennel (Foeniculum vulgare), a Mediterranean Apiaceae. Two nuances: (1) the deep etymology of μάραθον is itself uncertain, Beekes judges it probably pre-Greek, of foreign origin; (2) the idea that the plain 'teemed' with fennel is a traditional explanation of the place name, plausible but not proven by an ancient source describing the site's flora.
Key takeaways
- • Prefers full sun exposure.
- • Ideal soil: light, drained.
- • Keep away from: Tomato.