Tumbleweed refers to the propensity of this plant to break of at the base and be blown around in the wind. Amaranthus is from the Greek meaning "not to wither" and refers to the persistent flower spike. Albus means white and refers to the light colour of the stems when dry.
Other Names:
Stiff Tumbleweed.
Summary:
A stout, annual, many-branched almost hairless herb to 1000 mm round with clusters of tiny flowers in the leaf axils. The stems turn white and rigid as the plant dries in summer. It breaks off at the base and is blown by the wind until it is trapped by obstructions such as fence lines.
Description:
Cotyledons:
Two.
Leaves:
Alternate.
Stipules -
Petiole - short.
Blade - Egg shaped to spear shaped or elliptic, 2-30 mm by 2-12 mm becoming smaller near the top. Sometimes with a red or purple tint. Hairless. With a very small pointed tip or rounded. Wavy edges. Obvious pale veins.
Stems:
200-1000 mm long. Many branched. White or pale. Rigid. Forms a globular structure that breaks off at the base when dry. Almost hairless. Sometimes with a red or purple tint.
Flower head:
Short, dense spikes in all leaf axils. 2 green narrowly oval bracts, 2-5 mm long, underneath flower head, stiff and tapering to a fine very sharp pointed cusps.
Flowers:
Inconspicuous. Greenish. Separate male and female flowers on the same plant. Female flowers more numerous then male flowers.
Bracts - Each flower has 3 green, membranous, spiny bracts that are longer than the perianth segments. 2-5 mm long. Spear shaped, narrowly egg shaped to narrowly oblong with rigid, awl shaped tips with a sharp point.
Ovary -
Perianth - 3 segments. Spear to spoon or awl shaped. 2mm long. Tip acute or with sharp cusps.
Stamens -
Anthers - 2 celled.
Fruit:
1 celled. Small bladdery bag. 1.5-2 mm long. Upper half deeply wrinkled and wider than the lower half. Opening by a transverse line around the circumference near the middle.
Seeds:
Dark brown to black. Lens shaped and circular in outline. 0.5-1mm wide. Single. Shiny. Flattened.
Roots:
Taproot.
Key Characters:
Biology:
Life cycle:
Annual.
Physiology:
Reproduction:
By seed.
Flowering times:
January to April.
December to May in the Perth region.
Seed Biology and Germination:
Vegetative Propagules:
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Origin and History:
Southern North America.
Widely naturalised in temperate regions.
Distribution:
ACT, NSW, SA, VIC, WA.
Habitats:
Climate:
Soil:
Plant Associations:
Significance:
Beneficial:
Moderately palatable. Tolerant of moderately saline areas.
Detrimental:
Weed of pastures, cultivation and disturbed areas. Builds up on fence lines, trapping sand and debris. Not readily grazed by stock.
Toxicity:
Not reported as toxic, but closely related species may have toxic levels of oxalate and nitrate.
Legislation:
None.
Management and Control:
Improving pasture growth usually controls this weed.
Thresholds:
Eradication strategies:
Herbicide resistance:
Biological Control:
Related plants:
Boggabri weed (Amaranthus mitchellii)
Dwarf Amaranth (Amaranthus macrocarpus)
Foxtail (Amaranthus paniculatus)
Green Amaranth (Amaranthus viridis)
Love lies bleeding (Amaranthus caudatus)
Native Amaranth (Amaranthus interruptus)
Needleburr (Amaranthus spinosus)
Powell's Amaranth (Amaranthus powellii)
Redroot Amaranth (Amaranthus retroflexus)
Redshank (Amaranthus cruentus)
Rough fruited Amaranth (Amaranthus muricatus)
Slim Amaranth (Amaranthus hybridus)
Spreading Amaranth (Amaranthus deflexus)
South American Amaranth (Amaranthus quitensis)
Amaranthus graecizans.
Batchelor's Buttons (Gomphrena spp.)
Cockscomb (Celosia spp.)
Plants of similar appearance:
Kochia (Kochia scoparia).
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P69. Photos.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P330.
Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P160.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P282. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #68.1.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). p93.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.