Department of Environment, Water and Natural Resources

Maireana decalvans (Black cotton-bush)


Maireana decalvans (Black cotton-bush) Flower


Maireana decalvans (Black cotton-bush) Seeds


Appearance and Pollinators:

The Maireana decalvans or Black cotton-bush has fairly inconspicuous flowers. It has green winged frut (perianth) rather than petals. The pollinators for this fruit are believed to be native bees, moths or butterflies although specific pollinators are unknown. It is believed ants disperse the fruits of the bush. Unfortunately the biology of this species is not fully known, which is the case for many of Australia's native plants.


Height and Growing Conditions:

Shrubs grow to approximately 50cm high and have fleshy leaves and woody, branched stems. Fruits have a radial wing with a single slit. Fruits may be present from November to May and turn from green to brown on ripening. This plant grows best on heavy seasonally waterlogged soil and will grow in semi shade to full sun.



Seeds of this plant may be sown anytime of year and should germinate readily with no pre-treatment. Germination is rapid and seedlings should emerge within a couple of weeks after sowing.


Seeds will grow from inside the fruit in this species. The seeds should be planted in a seddling tray filled with premium potting mix or native potting mix to a depth of approximately 0.5cm and press in. Keep seedlings moist and pot up into tube stock pots when a few leaves have expanded. Take care not to disturb the root system when transferring the plants into fresh pots.


Collecting the Seeds:

The seeds of this bush should be collected when the papery winged fruits from the blue-bush have turned brown and have dried off. Mature fruits are easily collected by hand and will fall readily from the bush. These seeds should be stored in paper bags.




As part of the Botanic Gardens seed conservation centres Stewardship of Endangered, Endemic and Daimen Species, Roma Mitchell Secondary College has been given the Malreans decalvans or Black cotton-bush to plant and also create awareness for. This bush is currently an endangered species in South Australia but the Botanic Gardens and Roma Mitchell Secondary College hope to change this over the coming years.