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EnviroNorth > North East Queensland > Weeds > Shrub and Forb weeds

Shrub and Forb weeds

Lantana

Lantana camara forms vast, impenetrable thickets. The stems are prickly and difficult to walk through; the foliage is toxic to cattle, horses and humans; and the thick, aggressive stands smother native bushland and effectively prevent any regeneration by native plants. It is known to be allelopathic, which means that it produces chemicals specifically designed to retard the growth of other plant species around it. Efforts are being made to try to control lantana using biological control.

Bellyache bush

Bellyache bush (Jatropha gossypifolia), a plant predicted to become just as problematic as lantana, is now spread throughout Queensland, Northern Territory and Western Australia. It is declared in the Northern Territory and infests around one-sixth of that region, but some of the worst infestations are in the upper reaches of the Burdekin and around Charters Towers in northern Queensland. Bellyache bush forms dense thickets which exclude native plants and wildlife and is quite toxic.

Mother of millions or Bryophyllum spp.

Mother of millions

Another highly toxic and recently declared weed is mother of millions or Bryophyllum spp. This is a very popular ornamental plant as it takes no skill or watering to grow. Merely pulling the plant out is not enough and a bare-rooted plant can survive for months. If you burn it you would do well not to inhale any of the fumes as this may cause poisoning.

Parthenium can cause dermatitis, hay fever and asthma Photo: Greg Calvert

Parthenium

Parthenium (Parthenium hysterophorus) is a herb that can grow to two metres tall with carrot-like leaves and white flowers. Although it can smother fields and will grow just about anywhere, it is specifically targeted by many weed control agencies not because of its environmental problems, but because it causes severe dermatitis, hay fever and asthma in many people.

Yellow oleander

Yellow oleander or Thevetia peruviana , has also escaped from manicured gardens and gone bush. Although not present in large numbers yet, it could be dangerous to firefighters if they were to inhale fumes from this weed during grassfires. Breathing smoke, eating any part of the plant or even stirring your tea with a twig can result in severe poisoning.

Chinee apple woodland with large pocket of prickly acacia, south of Home Hill, Queensland Photo: Greg Calvert

Chinee Apple

Also known as chonky apple, Indian jujube or by its scientific name Zizyphus mauritiana, this thorny tree comes from Africa and southern Asia where it is a popular ornamental tree. They are fast growing, fire and chain-saw resistant, form pure mono-cultured stands and can reproduce rapidly. A single tree can produce 8–10,000 seeds a year. These seeds can be spread by floods, cattle or by wildlife such as agile wallabies. Chinee apple is a Class 2 declared weed in Queensland, which means landowners must take reasonable steps to keep land free of the weed. This can be an extremely expensive process but it is a job which many people are now starting to confront in the north-east Queensland area.