English Broom (Cytisus scoparius) is also known as Scotch broom, Common broom and Spanish broom, and invades natural ecosystems; it competes with indigenous plants and changes fauna habitat. On pasture broom forms thickets, preventing grazing and restricting access to water.
- non-spiny shrub with erect, spreading stems which later collapse to become prostrate
- plants grow to 4m high, often forming dense thickets in cooler areas
- branches are green, five-angled and mostly hairless
- leaves are usually three-foliate (like clover), 5mm long and 1mm wide, with scattered hairs on upper side and dense short hairs on underside
- flowers are on a stalk and solitary or in pairs, petals are golden yellow, 15mm long
- seed pods are oblong, 2cm long and 8mm wide, initially green then black at maturity.
Why is it a problem?
- groundcover plants and eucalypt seedlings are shaded out by dense broom stands
- provides shelter for pest animals, such as wild pigs and horses
- seeds are poisonous if eaten in quantity whilst foliage may cause digestive problems in horses
- forms thickets on pastureland that prevent grazing and restrict access to water.
- Northern agricultural districts and Yorke Peninsula – possible isolated patches
- Murray Mallee – isolated to roadsides in higher rainfall areas
- South East – isolated patches around Mt Gambier
- Central region – scattered heavy infestations in paddocks and roadsides
- The total area infested in Australia is estimated currently to be over 200 000 hectares and it is still spreading.
- fire encourages seed germination
- seeds are mostly shed from January to early march
- plants may live for up to 25 years or more in Australia
- seed longevity contributes to large soil seed banks - there can be up to 50,000 seeds per square metre under mature infestations
- frosts appear to have no impact on plants and mature plants tolerate summer droughts.
How it spreads
Seed is dispersed by:
- mud on vehicles, machinery, footwear and animals
- watercourses in flood
- animal dung, such as horses and pigs
- deliberate planting for beautification
- soil movement for roadworks in infested areas.