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Weeds in Australia

© Bill Richardson

Cape Broom/Montopellier Broom

Genista monspellullana

CAPE Broom is a regionally controlled weed in West and East Gippsland Catchment and Land Protection Regions, where landholders must take all reasonable steps to control this weed and prevent its spread on their land and on the roadsides which adjoin their land.

Cape Broom is native to scrub and open woodlands in the Mediteranian region, Portugal and the Azores. It was probably introduced to Australia as a garden or hedge plant and was widely planted here last century.

In Victoria, Cape Broom infestations occur mainly on grazing lands and dry sclerophyll forests and woodlands of southern, central and north-eastern regions.

Cape broom is an upright evergreen shrub up to three metres high, but more commonly one to two metres, reproducing by seed. Young plants are capable of flowering and fruiting at approximately two years old.

The stems are erect, ridged and woody, usually one stem with many branches. The leaves consist of three leaflets attached centrally to a short stalk, with the central leaflet slightly longer than the rest, up to 4Omm long. Leaflets have less hair on the upper surface than the lower.

The flowers are bright yellow and pea-like, occurring singly or in clusters of up to nine, in the leaf axils and at the ends of branches. Flowering occurs mainly from late winter to spring, but can also occur towards the end of summer.

The fruits are brown to black flattened pods, narrow and oblong in shape, 1.5 to 2.5cm long, 5mm wide, densely covered with long silky hairs. The pods appear in late spring and summer and coils after the seed is released.

Cape broom is capable of forming dense thickets on grazing lands, in native vegetation and on roadsides, which exclude most other vegetation. Dense infestations of Cape broom provide harbor for rabbits and foxes and increase fire fuel loads in native vegetation and areas. In native vegetation, Cape broom excludes desirable indigenous species. Cape broom is considered toxic to stock if grazed excessively, but in Australia no cases of poisoning have been reported.

The seeds of Cape broom are ejected with considerable force from the pod when it opens and may be dispersed several metres from the parent plant. Seeds may also be dispersed locally by ants. Road graders and earth moving equipment are probably the most important agents in longer-distance seed movement.

Other means of seed dispersal include slashing, water farm machinery and vehicles, contaminated agricultural products and animals moving through infested areas.

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