Weed Warning | Look out for groundsel bush in the Nambucca Shire

It’s a threat to the Nambucca Valley’s natural and agricultural environments because it readily invades disturbed areas, degraded pastures, open forests, and particularly wet lands and coastal swamps in humid warm-temperate to subtropical regions, according to information on the Department of Primary Industries NSW WeedWise website. 

The densely-branched shrub is usually 1.5 to three metres high, the leaves are dull or pale green, waxy to touch, alternate, 2.5 to five centimetres long, and one to 2.5 centimetres wide, wedge-shaped and prominently-toothed, particularly near the tip.

Each female plant during flowering (March to May) can produce more than 1.5 million seeds annually. The seeds are dispersal by wind and water. 

Thick stands of groundsel bush can inhibit native forest regeneration, the movement of stock and reduce the productivity and carrying capacity of agricultural land and is reputed to be poisonous to livestock although it seldom causes a problem because they rarely eat enough. However, livestock will lose condition rapidly if forced to graze it.

A variety of measures are available for controlling groundsel bush effectively such as regular slashing and pasture improvement in accessible areas, chemical control on fringes of paddocks and environmental areas.

Integrated pest management approaches such as the use of goats and biological agents are being used in core infestation areas to reduce its vigour and competitive ability.

Six insects and a rust fungus have been established in Australia, but only three of which, a fly and two stem-boring agents, have had a minor impact. 

Groundsel bush was first introduced into Australia as an ornamental plant and by 1900 had become naturalised in Queensland.

By 1930, it was a serious weed in south-eastern Queensland. By the mid-1960s, it was present in the Tweed, Richmond and Clarence catchments in northern NSW. Since then, it has gradually spread southwards along the coastal fringe to the Taree area. It is likely that groundsel bush will spread further in Australia.

Keegan Noble is a site leader on Nambucca Shire Council’s Green Space Team with a priority role as the invasive plants officer and natural area manager.

Working closely with Nambucca Valley Land Care, Keegan provides information and advice to local land owners about environmental awareness and management, including identifying noxious weeds in the area and how to manage them.

For advice from Keegan, contact council on 6568 2555.

Related reading: Saving endangered plant species in the Nambucca Valley