Boneseed

Chrysanthemoides monilifera subsp. monilifera

It is regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread, and economic and environmental impacts. Boneseed has become an aggressive invader of native bushland in Australia. Although it does not affect agriculture, it is considered a weed because of its ability to establish in areas of native vegetation ranging from mallee scrub to eucalypt dominated forests and, in particular, the coastal fringe. Its success is due to its vigorous growth, aided by an absence of natural enemies and the ability to regenerate quickly and outcompete other species after fire.

Description

Image of yellow flowering boneseed

Boneseed is a woody, perennial, much branched shrub, up to 3m high. The leaves are dull green, irregularly toothed up to 7.5cm long with short stalks and often have a covering of fine white hairs. The flowers are bright yellow with 4-8 petals occur at the ends of branches. Flowering time is July to October.

Boneseed growth calendar

Source: National Heritage Trust, Weed Management Guide

Spread

In Australia boneseed was originally planted as a garden species and to stabilise sand dunes. Birds are a major method of spread along with rabbits, foxes and cattle. Gravel carted from the You Yangs in Victoria has been a major method of spread from the infestation there. Boneseed has also been spread by dumping of garden waste.

OCCN uses Google maps to track the occurence of boneseed in the Otway Plain and Ranges coastal regions. Click here to access the map.

Control

When controlling Boneseed infestations first map out the infestation and plan how to approach removal. Remove small and scattered plants first on the outer edges of larger infestations and then moving in. Boneseed can be controlled at any time of the year but is best tackled when flowering as the shrubs are easily seen in August and September, but before fruiting in October.

Boneseed has shallow roots, with no distinct tap root and so handpulling or using mattocks is a great method for seedlings to medium plants. Dense thickets of small plants can be sprayed with herbicide. Larger established plants may be able to be handpulled or pushed over with tools as the root systems are shallow. Alternatively, larger plants can be cut off at ground level. Take care to apply herbicide immediately to the cut stump to prevent regrowth.

Biological control
Bitou tip moth (Comostolopsis germana), Bitou seed fly (Mesoclanis polana) and Bitou leaf rolling moth (Tortrix sp.) have been trialed as biological control agents. Unfortunately, none of these insects are having a significant impact on Boneseed.

More recently another agent, the Boneseed leaf-buckle mite, is being tested for release. Some of these test sites are located near Anglesea. Click here for more information on the Leaf-buckle Mite.