montpellier broom

Genista monspessulana
Shrub
Alternate
Compound
Yellow
Green

Usually evergreen shrub to 2.5 m tall with round, ribbed and softly hairy twigs, and ridged, woody, grey-brown stems. Leaves arranged alternately on stems, divided into three, with each leaflet (7-20 x 4-10 mm) usually hairy. Yellow to golden-yellow pea-like flowers (9-13 mm long) appear from May to November and are followed by oblong, densely hairy seed pods (18-20 mm long) containing 3-6 round, flattened, green to black seeds (2.5 mm diameter).

Common names 
Also known as: broom, canary broom, Cape broom, common broom, French broom, Madeira broom, Montpellier broom, soft broom,
Family 
Fabaceae
Deciduous 
No
Flowering time 
Autumn- Winter
Native/Exotic 
Exotic
Origin 
Mediteranian region
Notifiable 
No
State declaration 
Category 3 - Must not be distributed or disposed. This means it must not be released into the environment unless the distribution or disposal is authorised in a regulation or under a permit.
Council declaration 
As per State Declaration
Known distribution 

A widely naturalised species that is mostly found in the temperate regions of southern Australia. It is most common and widespread in Victoria, Tasmania, the ACT, southern and central New South Wales, south-eastern South Australia and south-western Western Australia. Also naturalised in north-eastern New South Wales, in south-eastern Queensland, and on Norfolk Island.

Habitat 

A weed of roadsides, railway lines, gardens, drains, fence lines, disturbed sites, waste areas, waterways, grasslands, open woodlands, forest margins and pastures. It is primarily found in temperate regions, but may occasionally also be present in sub-tropical regions.

Habit 

An upright (i.e. erect) and spreading shrub usually growing 1-2 m tall, but occasionally reaching up to 3 m in height.

Impact and control methods 

This species invades a wide variety of natural habitats including forest margins, dry coastal vegetation, heathlands, heathy woodlands, grasslands, grassy woodlands, open woodlands, damp sclerophyll forests, riparian vegetation and rock outcrop vegetation. Infestations shade and out-compete smaller shrubs and groundcover species, eventually replacing them and severely impeding the regeneration of overstorey plants. Such infestations are likely to have a major impact on the food sources of native fauna as well as reducing plant biodiversity. Because this species also fixes nitrogen, it increase soil fertility and often encourages other weeds to invade. Dense infestations can also increase the frequency and intensity of fires in invaded habitats, and such fires promote the germination of its seeds from a large and long-lived soil seed bank.

Stem and leaves 

Plants usually have one, short, much-branched woody stem that gives them a spreading appearance. Younger stems are ridged lengthwise (i.e. longitudinally) and softly hairy (i.e. pubescent).
The leaves are alternately arranged and borne on short stalks (i.e. petioles) 2-4 mm long. They consist of three relatively broad (i.e. elliptic to obovate) leaflets (i.e. the leaves are trifoliate). These leaflets (5-30 mm long and 2-15 mm wide) have entire margins and the middle (i.e. terminal) leaflet is usually larger than the other two (i.e. lateral) leaflets. The upper surfaces of the leaflets are bright green and slightly hairy (i.e. sparsely pubescent) or hairless (i.e. glabrous), while their undersides are somewhat hairy (i.e. pubescent).

Flowers and fruits 

The bright yellow flowers are pea-shaped (8-12 mm long) and borne on very short stalks (i.e. pedicels) 1.5-3 mm long. They are very numerous and either borne singly or in small clusters (containing 3-9 flowers). These clusters may occur at the tips of the stems as well as on short side branches (i.e. in terminal or lateral racemes). The flowers have five green sepals (4-7 mm long) that are partially fused together at the base into a short tube (i.e. calyx tube). The uppermost petal (i.e. standard) is larger than the two side petals (i.e. lateral or wing petals), and the two lower petals are fused together into a single entity (i.e. a keel) and are folded lengthwise. Flowering occurs mostly during late winter, spring and summer.
The fruit is a silky or downy (i.e. pubescent) pod that turns from green to brown or black in colour as it matures. These flattened pods (15-30 mm long and about 5 mm wide) contain five to eight seeds and become distinctly coiled after they open. The seeds (2-2.5 mm across) are dark brown to black in colour, smooth in texture and shiny in appearance. They are either rounded (i.e. globose) or somewhat flattened and have a small light brown coloured structure (i.e. aril) attached to them.

Reproduction and dispersal 

This species reproduces only by seed. These seeds are dispersed short distances (up to 3 m) when they are ejected from the mature pods. Longer distance dispersal can occur via vehicles, machinery, water, birds and other animals, and also in contaminated agricultural produce, soil and dumped garden waste.

Similar species 

Cape broom (Genista monspessulana) is similar to flax-leaf broom (Genista linifolia), Madeira broom (Genista stenopetala), broom (Cytisus scoparius subsp. scoparius), spiny broom (Calicotome spinosa), Spanish broom (Spartium junceum) and gorse (Ulex europaeus) at a distance. All of these introduced shrubs produce masses of yellow pea-shaped flowers.