Tree Hogweed
Polygonum patulum M. Bieb.
Family: - Polygonaceae.
Names:
Polygonum is from the Greek polys meaning many and gony meaning knee and refers to the many nodes on the stems.
Tree Hogweed.
Summary:
A tough, erect, wiry, groove-stemmed, much branched annual to perennial plant that grows to 800 mm tall.
Description:
Cotyledons:
Two. Lance shaped with an acute tip, 15 mm long. Hairless.
First Leaves:
Lance shaped with an acute tip. Red stem.
Leaves:
Alternate. Lower leaves broader than upper leaves.
Stipules - (Ochrea) Membranous, large, pointed, toothed sheath where the petiole joins the stem.
Petiole - Short, merges into blade.
Blade - Oval with an acute tip. Sides convex. Base tapered. Surface hairless.
Stems:
Erect, up to 800 mm, branched, tough, woody, stiff, lengthwise grooves. Hairless.
Flower head:
Single flowers in leaf axils.
Flowers:
Pink or white.
Bracts -
Ovary -
Perianth - Tubular with 5 pink or white lobes.
'Petals' - 5, pink or white.
Stamens -
Anthers -
Fruit:
Seeds:
Triangular pyramidal, shiny, 2-4 mm long.
Roots:
Strong taproot.
Key Characters:
Biology:
Life cycle:
Perennial, annual or biennial. Seeds germinate in autumn and winter.
Physiology:
Reproduction:
By seed.
Flowering times:
Spring.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
Europe.
Distribution:
NSW, QLD, SA, VIC, WA.
Habitats:
Climate:
Temperate.
Soil:
Gravel loams.
Plant Associations:
Significance:
Beneficial:
Detrimental:
Weed of crops and pastures.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Thresholds:
Eradication strategies:
Cultivate before flowering.
Glyphosate, dicamba and sulfonyl urea herbicides provide good control.
Herbicide resistance:
Biological Control:
Related plants:
Black Bindweed (Polygonum convolvulus)
Creeping Knotweed (Polygonum prostratum)
Pale Knotweed (Polygonum lapathifolium, Polygonum lanigerum)
Princes Feather (Polygonum orientale)
Sand Wireweed (Polygonum arenastrum)
Slender Knotweed (Polygonum salicifolium, Polygonum decipiens)
Small Knotweed (Polygonum plebeium)
Spotted Knotweed (Polygonum strigosum)
Vietnamese mint (Polygonum odoratum)
Water Pepper (Polygonum hydropiper)
Wireweed (Polygonum aviculare) has a smaller cotyledons (7 mm compared to 15 mm long), flowers, seeds and ochrea and more prostrate stems.
Polygonum capitatum
Polygonum glabrum
Plants of similar appearance:
References:
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). #1002.12.
Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne). P137. Diagrams. Photos.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.