Polygonum is from the Greek polys meaning many and gony meaning knee and refers to the many nodes on the stems.
A climbing annual vine with heart shaped leaves on long petioles and a loose spray of small green to whitish flowers on a long slender stalk.
Two that form and obtuse V. Hairless, usually reddish, 15-20 mm long, with a short merging petiole or none. The seedling has a long hypocotyl but no epicotyl.
Develop singly and have a heart shape, 20-30 mm long with a 5-10 mm long petiole. Later leaves are similar but larger.
Alternate. Does not form a rosette.
Stipules - (Ochrea) red-brown, membranous sheath, cut off at an angle on top with translucent tiny hairs. Edges smooth or becoming slightly tattered with age.
Petiole - Long, 25-50 mm long, slender with very short, bent back, translucent hairs.
Blade - 30-60 mm long by 20-50 mm wide, heart to arrow shaped with a pointed tip. Sides convex to angular. Base indented. Hairless or very short, low lying, translucent hairs on the veins and very short, translucent, triangular hairs on the edges.
Slender, scrambling, twining and climbing, up to 2000 mm long, circular or polygonal in cross section with shallow grooves and a small hollow in the core. Branched at the base with a few shorter branches along their length. Hairless or very short, bent, translucent hairs. Elongate in late winter.
A loose, slender, spike like raceme at the ends of branches or in leaf axils with 1-6 flowers.
2 mm long by 3mm diameter, green-white with a translucent bract(ochreola) underneath.
Ovary - 3 short styles. 3 stigmas.
Perianth - Tubular with 5, green to whitish, lobes split to about the middle. Edges of lobes translucent. 3 outer lobes obtusely keeled. Tiny translucent hairs.
'Petals' - 5, green to whitish.
Stamens - 8.
Nut or achene. Seed enclosed in the lower flower parts.
Black, triangular pyramid, hard nut, 3-5 mm long, dull or shiny, with minute warts on the surface.
Flowers in loose spike like racemes.
Stems slender, climbing.
Leaves sagittate or cordate.
Annual. In Tasmania seed germinates from spring to early summer whilst on the mainland germination is mainly in the autumn and winter. Flowers October
Summer in western NSW.
October in Perth.
Seed Biology and Germination:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
Europe. Asia. Africa. North America.
ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Common in the North-West and North-East of Tasmania, less frequently found in the South and local occurrences only in the Midlands.
Higher rainfall areas.
Weed of cereal crops, vegetables and disturbed areas. Its climbing habit can smother crops and cause lodging.
Seeds may be toxic to stock.
Management and Control:
Cultivate before flowering.
Glyphosate, dicamba and sulfonyl urea herbicides provide good control.
No other significant Fallopia species are recorded for Australia, however, Black Bindweed was included in the Polygonum genus previously.
Creeping Knotweed (Polygonum prostratum)
Pale Knotweed (Polygonum lapathifolium, Polygonum lanigerum)
Field Bindweed (Convolvulus arvensis) is similar but the cotyledon shapes, ochrea and flowers are different.
Redshank (Persicaria maculosa) has a dark blotch in the middle of the leaves.
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P203. Photo.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P283. Diagrams.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P231.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P199.
Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P52-53. Diagrams.
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). #1002.4.
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). P113.
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