Family: Fabaceae (peas)

Status: English broom is declared Noxious in all south coast Local Government Areas, in category W2 (must be continuously suppressed and destroyed). Cape broom is only declared noxious in Bega Valley Shire (W2).

Description:
All three broom species are shrubs from 1-2 metres high, with pure bright yellow pea flowers in spring, followed by hairy seed pods. Flax-leaf and cape broom are very similar, having leaves composed of three leaflets, like clover. The leaflets are narrower in flax-leaf broom. English broom is generally leafless, with the flowers borne on green ribbed stems. Younger plants may have a few leaves composed of either one or three leaflets.

Preferred habitat and impacts:
Garden escapees, usually found close to towns or old farmhouses. However, dumping of garden refuse may spread the seed some distance from habitation, particularly along roadsides.
Brooms, and the closely related gorse, are very bad weeds of cooler areas, where they can come to dominate the understorey of otherwise undisturbed open forest and woodland. They do not like deep shade. Allegedly sterile hybrid forms of both Cytisus and Genista brooms are still sold in nurseries. These have been observed to produce seed and revert to the wild type, and should not be planted.
Being legumes, the brooms fix nitrogen, and can increase soil fertility, encouraging other weeds to invade.
Dense infestations provide rabbit harbour.

Dispersal:
Dumped seed-bearing garden waste or movement of seed-contaminated soil. Explosive release of seeds around parent plants.

Look-alikes:
Gorse (Ulex europaeus) is another weed in the pea family with pure yellow flowers and hairy pods. It is a very spiny large shrub, with similar 3-foliolate leaves on young plants, becoming leafless with age. It is a weed of the tablelands, and is uncommon on the south coast. It is a Weed of National Significance, and declared noxious in Shoalhaven and Illawarra LGA’s.

Tree lucerne or tagasaste (Chamaecytisus palmensis) is an environmental weed with larger 3-foliolate leaves, white pea flowers and flat furry seed pods. It grows into a small spreading tree.
Spanish broom (Spartium junceum) is a similar leafless shrub to English broom, but has smooth, not ribbed, stems. It is not very commonly planted, but it is potentially invasive.
There are a number of native shrubs in the pea family which have some of the features of the brooms. Most native pea shrubs have yellow flowers with blotches of brown, red or orange, not pure yellow. Gompholobium species have leaves with 3 leaflets and pure yellow flowers, and Goodia lotifolia has 3 leaflets and yellow flowers with a touch of red, but neither have hairy pods. Jacksonia scoparia is a leafless shrub, but its stems are silvery-grey, not green, and often weeping in habit, except in young plants. Its flowers are a deep yellow, and pods are tiny and not hairy. It grows to about 3m, and has thick furrowed black bark. The leafless native pea Viminaria juncea has a more upright habit, green stems and flowers with a touch of red. It grows in swampy situations.

Control:
For large broom or gorse plants, cut and paint. Seedlings and smaller plants can be hand-pulled or dug out. Seed is long-lived in the soil and seedling growth after removal of the parent plants will need follow-up work. Spray if seedling growth is prolific, or hand-pull. Prolific seed production and long viability means a large soil seed bank, which will continue to germinate for many years after mature plants are removed. Fire may be helpful in germinating most seed so seedlings can be sprayed.