|Common name:||wheel cactus|
|Scientific name:||Opuntia robusta H.L. Wendl. ex. Pfeiff.|
|Other scientific name/s:|
|Other common name/s:||wheel pear|
Catchment management authority boundaries
Regionally prohibited in the Port Phillip and Western Port Catchments
Regionally controlled in the Mallee, Wimmera, North Central and North East Catchments
Restricted in the Glenelg Hopkins, Goulburn Broken, West Gippsland, East Gippsland and Corangamite Catchments
Shrub (or bush)
An erect succulent shrub growing to 1-2 m high.
Consist of a series of blue-green fleshy segments (also known as joints, pads or cladodes) which are commonly thought of as leaves but are really flattened stems. Segments are circular growing, to 40 cm in diameter, flat, glabrous and armed with tufts of numerous barbed bristles (glochids); commonly found with one to five sharp spines growing to 4 cm long arising from each areole.
Small, scale-like, produced beneath the areoles on young segments only; which are shed as segments when mature.
Yellow petals with reddish streaks on the back. Flowers are about 5-8 cm in diameter, sessile, with a fleshy base, produced mostly on the upper margins of terminal segments.
Pink to purple and barrel-shaped growing to 8 cm long and 6 cm in diameter, with dark red flesh bearing tufts of fine barbed hairs or bristles in areoles.
The root system of the wheel cactus is shallow and fibrous.
Growth and lifecycle
Method of reproduction and disperal
The weed produces viable seed, which can be spread in the droppings of birds, foxes and other animals over large distances. The plant reproduces by seed and also propagates from branch segments.
Rate of growth and spread
Once established, individual wheel cactus plants can live for several decades.
Seedbank propagule persistence
Wheel cactus produces numerous fruits, with each fruit containing numerous seeds.
Wheel cactus prefers arid and semi-arid areas in warm temperate and sub-tropical regions, where it grows well on shallow granite soils. The plant is drought-resistant.
It has become weedy in isolated areas of Victoria, particularly in the north central region.
The icons on the calendar below represent the times of year for flowering, seeding, germination, the dormancy period of Wheel cactus and also the optimum time for treatment.
Impact on ecosystems and waterways
In dense patches, aerial growth provides good ground cover. The weed grows densely, forming impenetrable barriers; stands can hinder growth and regeneration of indigenous plants, smaller shrubs and ground flora, resulting in a major impact on lower stratum and a minor impact on mid stratum flora.
Wheel cactus is not usually grazed by stock because of its stout spines. In dense patches, the plant could hinder access to water and reduce food available for fauna.
Being long-lived, patches of the plant also provide effective and permanent harbour for pest animals such as rabbits.
Agricultural and economic impacts
Wheel cactus is not a weed of cropping or intense grazing land, however animals avoid the plant because of its spines and dense patches may limit grazing capacity. Presence of the weed is not likely to affect land value.
Social value and health impacts
Patches of wheel cactus grow densely forming an impenetrable barrier, in some instances the plant was used as hedging. Where established, the weed is most likely to restrict human access.
The plant may also affect some recreational activities.The barbed bristles of the wheel cactus are sharp, readily penetrating human skin causing severe irritation and are difficult to remove.
Prescribed measures for the control of noxious weeds
- Application of a registered herbicide
- Physical removal
Other management techniques
Changes in land use practices and spread prevention may also support wheel cactus management after implementing the prescribed measures above.
Blood, K. 2001, Environmental weeds. a field guide for SE Australia, CH Jerram, Science Publishers, Mt Waverley, Victoria, Australia.
Carr, G.W., Yugovic, J.V. and Robinson, K.E. 1992, Environmental weed invasions in Victoria: Conservation and management implications, Department of Conservation and Natural Resources and Ecological Horticulture, Victoria.
Muyt, A. 2001, Bush invaders of south-east Australia. a guide to the identification and control of environmental weeds found in south-east Australia, R.G. & F.J. Richardson, Victoria.
Parsons WT & Cuthbertson EG 1992, Noxious Weeds of Australia, Inkata Press, Melbourne and Sydney.
Parsons, W.T. and Cuthbertson, E.G. 2001, Noxious weeds of Australia, 2nd edn, Inkata Press, Melbourne & Sydney.
Department of Primary Industries, Wheel Cactus Regionally Prohibited Weed Fact Sheet, February 2010