Fennel

Foeniculum vulgare Miller

Synonyms - Foeniculum officinale

Family: Apiaceae.

Names:

Foeniculum is from the Latin foenum for hay and refers to its aroma.
Vulgare is from the Latin vulgaris meaning common.
Fennel is derived from the generic name.

Other names:

Aniseed
Dill
Anise
Sweet Anise
Vinkel (South Africa).

Summary:

A fine leaved perennial shrub with erect, many branched stems reaching 2 m or more tall and a strong aniseed-like smell. The yellow-green flowers are in compound umbrellas at the top of the plant from late winter to summer.

Description:

Cotyledons:

Two. The cotyledons are elongated and narrow, some 40-50 mm long. There is a hypocotyl and a short and indistinct epicotyl.

Leaves:

Alternate, form a basal rosette, aromatic, aniseed scent.
Stipules - None.
Petiole - Hollow, long, broad and sheathing the stem with a pale, V shaped sheath. Less well developed on upper leaves.
Blade - Up to 450 mm long. Compound, feathery, divided 2-4 times into thread like segments 2-50 mm long. Later rosette and stem leaves more divided than early leaves. The leaflets are very fine. Tip has a tiny point and is leathery. Hairless.

Stems:

Erect, faintly striped, solid with white spongy pith, stout, aromatic, aniseed scent, tufted or branched and with several stems emerging from each crown, Up to 2500 mm tall. Jointed at the nodes. Hairless. Often with a waxy bloom.

Flower head:

Umbels in a terminal corymbose panicle. Many flowers produced together in the umbrella-like compound umbels on a stalk (peduncle) with 10-40 spreading rays that are 10-50 mm long and end in a small umbrella like structure with 10-30 flowers. No bracts or ray bracts.

Flowers:

Green-yellow and 2-6 mm in diameter and bisexual. On different length, ridged, short stalks (pedicels).
Bracts - None.
Ovary - Short style with a conical enlarged base.
Sepals - A thickened rim without lobes.
Petals - 5, yellow, oblong, lobed or with a broad shallow notch. Incurved tips.
Stamens -
Anthers - Almost circular in outline.

Fruit:

Grey to yellow brown, aromatic, short, oblong, cylindrical, 3-6 mm long x 1-2 mm wide, with 2 flattened, arched, egg shaped fruitlets with 5 thick ribs, a pointed tip and a rounded base. Hairless. Axis separating fruits is persistent, 2 lobed with a broad seam and 2 oil channels, (6 in total with 1 in each furrow).

Seeds:

Roots:

Strong, stout, branched taproot with many laterals and a prominent crown.

Key Characters:

Liquorice like (aniseed) odour.
Green yellow flowers in an umbrella like head.

Biology:

Life cycle:

Biennial or short lived perennial. The main germination occurs in autumn or spring. Plants initially grow as a coarse rosette, and often do not flower until they are about 2 years old. Regeneration from established roots and the old lower stems occurs in late winter to spring and many leaves are produced in a basal rosette before the flowering stems emerge. Many of the leaves die as the flower stems mature. The plant flowers in summer. Top growth generally dies down over winter.

Physiology:

Frost tolerant.

Reproduction:

By seed and from the crown.

Flowering times:

Late Spring to summer in western NSW.
September to December in SA.
July to January in Perth.
Late spring and summer in WA.

Seed Biology and Germination:

Germinates at any time of the year with a flush in autumn and spring.

Vegetative Propagules:

Crown.

Hybrids:

Cultivated varieties exist. Variety dulce or Florence Fennel and azoricum is used for food, variety vulgare for medicine.

Allelopathy:

Tomatoes and beans don't grow in association with Fennel.

Population Dynamics and Dispersal:

Spread by vehicles, machinery, flowing water, on animal coats, wool clothing, hides and as a contaminant of agricultural produce and land fill.
Pieces of crown and roots dislodged by machinery will readily spread and re grow.

Origin and History:

Southern Europe and Western Asia.
First recorded in Australia in 1803 and naturalised by 1880.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Locally common in the south, the north and the north-west, and less frequently encountered in other parts of Tasmania.

Courtesy Australia's Virtual Herbarium.

Habitats:

Prefers open unshaded areas.

Climate:

Humid temperate with medium to high rainfall.

Soil:

Most abundant on limestone soils and calcareous wetlands.
Grows on a wide range of soil types that are moist in summer.

Plant Associations:

Significance:

Beneficial:

Cultivated strains are used in cooking. Leaves are chopped and used as garnish. Seeds are used as a flavouring in bread or stews. Leaves are cooked with meat and fish for flavouring. Petioles, young shoots and roots are cooked as vegetables. Petioles are also eaten raw.
Used for production of anethol oil that is used as food and beverage flavouring and in the liqueurs like absinth.
Honey plant.
Herb.
Used in herbal medicine for many different ailments.
Used in beauty treatments and air fresheners.

Detrimental:

Weed of roadsides, railways, stream banks, alluvial flats, irrigation channels, gardens, refuse sites and disturbed areas, particularly in suburban areas.
Many people consider the plant to have an offensive or even nauseating smell.
Not grazed by stock.

Toxicity:

Death of sheep and cattle have occurred after eating residues from distillation plants. Stubbles do not appear to be toxic and it is rarely if ever a problem in field situations.

Legislation:

Noxious weed of Vic. Secondary weed of Tas.

Management and Control:

Thresholds:

It can form dense infestations that exclude most other species. Once established it is a strong competitor.

Eradication strategies:

Manually remove isolated plants. A hand mattock that cuts the root below the surface is often used.
Deep cultivation is effective.
It rarely persists in well grazed or regularly cultivated areas.
A number of herbicides provide good control.

Herbicide resistance:

Biological Control:

Related plants:

None.

Plants of similar appearance:

Aniseed plant (Pimpinella anisum) has a similar aroma and is in the same family.
Hemlock (Conium maculatum) has hollow stems with no pith.
Wild Carrot (Daucus carrota) has white flowers with a single central dark blue flower.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P75. Photos.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P663. Diagram.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P287-288. Diagram.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P542. Photo.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P84. Photo.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania). P70-71. Diagrams.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #556.1.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P507.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P170-172.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.