Montpellier Broom

Genista monspessulana (L.) L. Johnson

Synonyms - Genista canariensis, Teline monspessulana, Cytisus canariensis, Cytisus monspessulanus.

Family: Fabaceae.

Names:

Genista is the Latin name for this group of plants.
Monspessulana is Latin for Montpellier in France where the plant originated.
Montpellier Broom because it originated near Montpellier.

Other names:

Broom
Canary broom
Cape broom refers to Cape Verde near the Canary Islands because it was thought that this plant was Canary Broom.
Common broom
French broom (USA)
Montpellier broom
Soft broom (New Zealand)
Spanish broom.

Summary:

Montpellier Broom is an erect or slightly drooping shrub to 3 m high with ribbed branches. The alternate, trifoliate leaves have very short stalks; the individual leaflets are broad and flat, 5-20 mm long and 3-10 mm wide. The flowers are in dense terminal clusters of 3-7, each flower 8-11 mm long and almost hairless. The narrow, oblong seed pods are 3-5 mm wide with 6-7 seeds and are somewhat flattened and hairy.
Montpellier Broom is native to the Mediterranean region, was introduced as an ornamental shrub, and is often naturalised along roadsides and disturbed forest areas. It flowers in spring.

Description:

Cotyledons:

Two.

Leaves:

Alternate.
Stipules - small, egg shaped to triangular. Free from the petiole.
Petiole - short, 2-4 mm long.
Blade - 3 finger like leaflets. The leaflets are lance shaped to wedge shaped, fleshy, smooth edges with a rounded tip or a small point and on short stalks. Hairy when young especially on conspicuous midrib underneath, less hairy on top. Green on top, greyish underneath. Middle leaflet 5-40 mm long, side leaflets shorter.

Stems:

Green, erect, woody, angular, striped, grooved, up to 3000 mm. Crimped, short soft hairs. Longer spreading hairs also on young flowering shoots. Becomes hairless with age. Usually has a main stem with many branches. Stems coppice if damaged.

Flower head:

Racemose clusters, of 3-9 flowers, at the ends of short branches with a few single flowers in leaf axils at the base of lateral branches.

Flowers:

Pea type and bright yellow. 10-12 mm long. On a short stalk.
Bracts - narrow, papery attached to base of tube. Shorter than the tube
Ovary - Style is short and incurved.
Calyx - tubular, 5-6 mm long. Upper lip of 2 pointed lobes as long as the tube. Hairy, Lower lip with 3 short lobes tapering to a fine point. Hairy.
Corolla - bright yellow. Standard petal, 10-12 mm long. Keel hairy towards the top.
Stamens - united by filaments in a tube around the ovary.
Anthers -

Fruit:

Pod brown or black, slightly curved, 4-8 seeded, flattened, 15-25 mm long x 5 mm wide, with silky hairs. Seeds explosively released. Coils after seed is released.

Seeds:

Dark brown to black, smooth, shiny, rounded, flattened, 2 mm diameter.

Roots:

Branched taproot and many shallow laterals.

Key Characters:

Trifoliate leaves.
Yellow pea type flowers.

Biology:

Life cycle:

Perennial. Seeds germinate in autumn and spring and grow slowly to flower when around 2 years old. Flowers in late winter to spring and may flower again at the end of summer. Seed pods burst on hot days catapulting seeds several metres from the parent plant. Evergreen plant with new growth formed in winter and spring.

Physiology:

Drought tolerant once established.

Reproduction:

By seed.

Flowering times:

Late winter and spring and sometimes a minor flowering in late summer to autumn.
Summer in western NSW.

Seed Biology and Germination:

Seed may remain in the soil for many years.
Seed dormancy is broken by fire.

Vegetative Propagules:

None.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Seeds explosively released scattering them several metres from the parent and accounting for most of the local spread.
Initially the major spread was from intentional planting. Now most spread is due to road making machinery moving the seed to new areas and in water flows. Some spread may be due to birds. Some spread is in contaminated produce and mud on animals and machinery.
It produces large quantities of seed.
Large numbers of seedlings emerge when vegetation is removed.

Origin and History:

Mediterranean, Europe, Portugal, Azores.
Probably introduced to Australia as an ornamental hedge plant before 1850.

Distribution:

ACT, NSW, SA, TAS, VIC, WA.

Courtesy Australia's Virtual Herbarium.
Weed of Chile, New Zealand, South Africa, Hawaii and western states of the USA.

Habitats:

Climate:

Humid and sub-humid Mediterranean climates.
Prefers areas with more than 500 mm rainfall per year.

Soil:

Plant Associations:

Significance:

Beneficial:

Fermented flower buds are smoked and Mexican Indians use extracts as hallucinogens.
Ornamental used as a hedge plant and windbreak.
Fodder. Young plants are palatable.

Detrimental:

Weed of roadsides, railways, disturbed areas, watercourses and poorer pastures with an annual rainfall of more than 500 mm.
Forms dense thickets which excludes more desirable species and harbours vermin such as rabbits.
Forms an inflammable understorey on the edges of forests.

Toxicity:

Toxic if consumed in sufficient quantity. Sheep eat young plants without apparent problems if it is only a moderate portion of their diet. No cases of poisoning have been reported in Australia.

Symptoms:

Nausea, convulsions, respiratory failure then death.

Treatment:

Remove stock from infestations.

Legislation:

Noxious weed of VIC, SA and TAS.

Management and Control:

Grazing normally provides control.

Thresholds:

Forms dense thickets if left uncontrolled in suitable areas.

Eradication strategies:

Mechanically remove isolated plants and roots.
Seed dormancy is broken by fire and dense stands often develop after areas have been burnt. In denser infestations, slash, burn, then cultivate to kill emerging seedlings and sow perennial pastures to reduce reinfestation. Triclopyr plus picloram applied in spring provides good control. Repeat treatments are required for seedlings and regrowth from larger plants. Glyphosate is also used but high rates and repeated applications are required.

Herbicide resistance:

Biological Control:

Related plants:

Flaxleaf Broom (Genista linifolia) is a rounded shrub up to 3 m high. The leaves are stalkless; the individual leaflets are narrower, linear to oblong, 15-25 mm long and 0.5-2 mm wide, with rolled edges, the under surface silky hairy. The flowers are in clusters of 3-16, each flower 10-15 mm long with sparsely silky hairy petals. The seed pods are 5-6 mm wide with 2-4 seeds. Flaxleaf Broom is sometimes naturalised along roadsides. It flowers in late winter and spring and has a similar distribution to Montpelier broom but is usually less aggressive as an environmental weed.
Madeira Broom (Genista stenopetala) has a longer petiole at 6-15 mm long.

Plants of similar appearance:

Broom (Cytisus scoparius) has a longer and coiled style, larger flowers (15-25 mm) and the pods are only hairy on the edges.
White Spanish Broom (Cytisus multiflorus) has white flowers flecked with purple, grey green thinner stems
Gorse (Ulex europaeus) has darker flowers and is spiny. Its leaves are spine like and it only has trifoliate leaves on the seedling.
Spiny Broom (Calycotome spinosa) is spiny.
Spanish Broom (Spartium junceum) has larger (20-30 mm) fragrant flowers with one lobe on usually leafless stems.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P166. Photo.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P224.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). p422. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P421-422.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #580.3.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P478-480. Photos.

Acknowledgments:

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