Mimosa forms impenetrable thickets which blanket the landscape reducing biodiversity.

Sleeper weeds

Sleeper weeds could have significant impact on Australian agriculture and the environment if allowed to spread.

• 18 October 2006 | Updated 14 October 2011

Sleeper weeds are invasive plants that become established in a region but have not spread widely.

One example is Mimosa pigra (mimosa), which existed in low numbers for 70 years before becoming a major weed in the Northern Territory of Australia.

Many exotic plants have established in Australia but not become major weeds. This may be for a variety of reasons including:

• the absence of suitable pollinators
• unsuitable environmental conditions
• the presence of exotic natural enemies which were introduced with the plants.

However, this does not mean these plants will never become weeds. Some may be sleeper weeds which may one day, when conditions are right, begin to spread rapidly.

If these plant species could be identified and eradicated or contained before they become major weeds, then there would be a considerable saving in terms of the cost of control as well as loss of biodiversity.

The Bureau of Rural Sciences in the Australian Governments Department of Agriculture, Fisheries and Forestry has produced two informative reports on sleeper weeds:

1. Cunningham D, Woldendorp G, Burgess M, Barry S. 2003. Prioritising sleeper weeds for eradication: Selection of species based on potential impacts on agriculture and feasibility of eradication. Bureau of Rural Sciences, Canberra.
2. Brinkley T, Bomford M. 2002. Agricultural Sleeper Weeds in Australia. What is the Potential Threat? Bureau of Rural Sciences, Canberra.

Learn more about the Steps in a weed biological control program.