A plant which is predicted to be just as bad as Lantana is the
Bellyache Bush (Jatropha gossypifolia). This is from the Caribbean area
and was introduced as an ornamental around the turn of the century. It
is now spread throughout Queensland, Northern Territory and Western
Australia. It is declared in the Northern Territory and, hopefully,
will soon be declared in Queensland. The worst infestations I have seen
are in the upper reaches of the Burdekin and around Charters Towers,
although it apparently infests nearly one sixth of the Northern
Territory. It has recently become established in Townsville and I hope
that these small populations will be destroyed before they spread.
Bellyache Bush forms dense thickets which exclude native plants and
wildlife and is quite toxic. If you see this plant, kill it! Plants
like this won't wait until they are declared a noxious weed before they
act like one.


More information
http://farrer.riv.csu.edu.au/ASGAP/APOL16/dec99-2.html