Threats to its existence include urban expansion, habitat loss, weed invasion, human recreation and the dumping of rubbish.

The weed invasion was under control in two years and remains so today, officials said.

Potential threats to the latter population, estimated to be around 40 plants, include weed invasion, tramping, fire and grazing by rabbits.

Frequent fires, recreational activities and weed invasion have plagued Perth's urban bushland areas.

Potential threats include inappropriate fire regimes, weed invasion, grazing by stock and rabbits and mining for marble.

Nevertheless, the species still remains at severe risk of extinction, mainly through weed invasion of its unstable, volcanic cliff habitat.

This has left a legacy of land degradation, particularly soil salting, tree dieback, and weed invasion.

The colonists were unable to successfully manage their fields and the crops due to the loss of soil fertility and weed invasion.

As to weed invasion: one of the most prevalent weeds at this time of year is wild garlic.

Feral pigs have a large impact on the park and cause ground disturbance that encourages soil erosion and weed invasion.