Swamp corkwood, white dragon tree, dragon-flower tree, water tree
It is found in the Pilbara and Kimberley areas of Western Australia and eastwards to Arnhem Land in the Northern Territory. There is a small isolated occurrence on Cape York Peninsula, Queensland. The latitudinal range is 13-23o S and the altitudinal range is from near sea level to 550 m. (QLD, NT, WA)
A very fast-growing, nitrogen-fixing, small tree, usually 8-12 m tall but sometimes to 20 m, with few, more or less upright branches. The bark is pale grey, furrowed and corky. Young twigs are finely hairy. Leaves are pinnate, 15-40 cm long with 5-20 or more pairs of leaflets. The pea-shaped, white or yellowish-white flowers are 7-12 cm long and form clusters of 2-7 flowers. The pods are narrow and curved, 40-60 cm long and pointed at both ends. Flowering is in May - June and the pods mature August - September. The seeds are bean-like, smooth, shining and dark brown. There are about 31 000 viable seeds per kilogram. Germination may be improved by briefly immersing the seeds in boiling water.
Ecology/Way of Life:
This species occurs in the hot arid, hot semi-arid, hot sub-humid and hot humid zones. The area is frost-free. The mean annual rainfall is 230-1570 mm with a strong summer maximum. The rainfall data do not provide a good indication of water availability as this species frequently occurs along river banks, in depressions or where a high groundwater table exists. It grows mainly on alluvial plains where the soils range from deep sands to heavy, black, alkaline clays. This species tolerates saline and waterlogged conditions. It is a component of open-woodland, open-forest or closed-forest, commonly associated with Eucalyptus camaldulensis, Melaleuca leucadendra, Pandanus aquatica and Terminalia platyphylla.
Interaction with Humans/Threats:
The wood is white, soft, light and non-durable and is little used. The leaves have good potential as stock fodder. The tree has been used as a fast-growing, short-term plant in amenity and horticultural planting, for example as a nurse crop for mangoes and as secondary host for sandalwood. It makes an attractive ornamental for gardens and is useful for mixed shelterbelts, soil stabilisation, land rehabilitation and as a green manure. The flowers can be eaten raw or cooked. Australian Aboriginals used an infusion from the inner bark for treating sores and general illness. It has the potential to become a weed under certain conditions.
Sesbania formosa was named in 1965 by Nancy T. Burbidge, Curator of Herbarium Australiense in Canberra. The genus is based on Arabic seisaban, referring to the Middle Eastern sesban tree; the species name is from the Latin formosus = beautiful, referring to the flowers, which are the largest of any in the Australian pea family.
Brock, J. 2001. Native plants of northern Australia. Reed New Holland, Sydney.
Burbidge, N.T. 1965. The Australian species of Sesbania Scopoli (Leguminosae). Australian Journal of Botany 3: 103-141.
Doran, J.C. and Turnbull, J.W. (eds.) 1997. Australian trees and shrubs; species for land rehabilitation and farm planting in the tropics. ACIAR Monograph no. 24. Australian Centre for International Agricultural Research, Canberra. 384p.
Petheram, R.J. and Kok, B. 1983. Plants of the Kimberley region of Western Australia. University of Western Australia Press, Nedlands, Western Australia.
Topics:Soils Waterlogging Fodder Firewood Timber Vegetation types Ornamental Windbreak Nitrogen- fixation Germination Invasive species/Weeds
Text & map from Australian Trees and Shrubs, courtesy Australian Centre for International Agricultural Research; text edited by J. Turnbull; photo courtesy B. Gunn..
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