Polygonaceae - buckwheat family
 

WeedsPoisonous PlantsHay Fever
Gerald A. Mulligan (Agriculture Canada, Ottawa, retired)
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Fagopyrum tataricum (L.) Gaertn., Tartary buckwheat, sarrasin de Tartarie
Annual, spreading by seeds; stems erect, to 2 feet (6 dm.) high; weedy only in the mid-west; grain fields, roadsides, and waste places; introduced from Asia.

Polygonum achoreum S.F.Blake, striate knotweed, renouée coriace
Annual, spreading by seeds; prostrate to semi-erect; flowers small; nearly throughout; roadsides, and waste places; native to North America.

Polygonum aviculare L., prostrate knotweed, renouée des oiseaux
Annual, spreading by seeds, prostrate to semi-erect; autogamous; flowers very small; throughout; cultivated fields, roadsides and waste places; common in settlements, particularly on trampled ground; the first seed to germinate in severely disturbed habitats adjacent to roads and walkways after the ground unfreezes in the spring; introduced from Europe and Asia.

Polygonum convolvulus L., wild buckwheat, renouée liseron
Annual, spreading by seeds; autogamous; stems slender, trailing on the ground or twining about other plants; lacking petals; throughout, but most common in mid-west; grain fields; row crops, gardens, roadsides, and waste places; introduced from Europe.

Polygonum cuspidatum Sieb. & Zucc. (= Fallopia japonica (Houtt.) Ronse Decr.) Japanese knotweed, renouée du Japon
Perennial, spreading from underground stems; small flowers creamy white; herbaceous shrub-like clumps of stems 5 to 12 feet (16 to 40 dm) heigh; common throughout in all but the drier regions; gardens, old fields, hedgerows, shores, forest edges, thickets, roadsides and disturbed areas. Introduced from eastern Asia.
Text and photos of Japanese knotweed by Stephen J. Darbyshire

Polygonum lapathifolium L., pale smartweed, persicaire pâle
Annual, spreading by seeds; stems 1 to 5 feet (3 to 15 dm.) tall; flowering spikes nodding, usually pink; throughout, but commoner in mid-west; grain fields, cultivated fields, roadsides, and waste places; both native to North America and introduced from Europe.

Polygonum persicaria L., lady's-thumb, renouée persicaire
Annual, reproducing by seeds; autogamous; stems 6 inches to 3 feet (15 cm. to 9 dm.) high; flowering spikes pink or reddish; throughout; grain fields, cultivated fields, roadsides, and waste places; introduced from Europe.

Polygonum scabrum Moench, green smartweed, renouée scabre
Annual, spreading by seeds; autogamous; stems 1 to 3 feet (3 to 9 dm.) high; flowering spikes whitish; throughout, but most common in east and west maritime regions; grain fields, cultivated fields, roadsides, and waste places; introduced from Europe.

Rumex acetosella L., sheep sorrel, petite oseille
Perennial, spreading by seeds, and underground rootstocks; up to 1 foot (3 dm.) high; throughout, but rare in mid-west; meadows, pastures, roadsides, and waste places; introduced from Europe and Asia. Allogamous, with male and female flowers on separate plants.

Rumex crispus L., curled dock, patience crépue
Perennial, spreading by seeds; stems up to 3 feet (9 dm.) high; flowers inconspicuous; throughout, but most common in the east; meadows, pastures, roadsides, and waste places; introduced from Europe and Asia.

Rumex longifolius DC. [ =Rumex domesticus Hartm.], long-leaved dock, patience à feuilles longues
Stout perennial, up to 30 inches (75 cm.) high; flowers inconspicuous; throughout, but most common in inland-east; pastures, roadsides, and waste places; introduced from Europe and Asia.

Rumex pseudonatronatus (Borbás) Murb. [=Rumex fennicus (Murb.) Murb], field dock, patience de Finlande
A slender perennial plant; stems up to 5 feet (15 dm.) high. It is more abundant than curled dock in the Midwest, but it is a rare plant elsewhere. Roadsides, waste places, shores, meadows, cultivated fields. It often occurs in slightly saline soils. Introduced from Europe and Asia.

Rumex stenophyllus Ledeb., serrate-valved dock, patience à feuilles étroites
A perennial; stems from 3 to 4 feet (9 to 12 dm.) high. It is common in the Midwest, but it is rare elsewhere. Waste places, roadsides, fields, meadows, swamps, and marshes. It is often in saline soils. Introduced from Europe.

Rumex obtusifolius L., broad-leaved dock, patience à feuilles obtuses
A perennial plant; stems up to 3 feet (9 dm.) high. Throughout, except the Midwest. Waste places, roadsides, fields, shores, meadows, wet woods, and swamps. Introduced from Europe.

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Weed Name Photo Weed Name Photo
Tartary buckwheat, sarrasin de Tartarie
(F&M)
Tartary buckwheat, sarrasin de Tartarie
striate knotweed, renouée coriace striate knotweed, renouée coriace
prostrate knotweed, renouée des oiseaux and striate knotweed, renouée coriace
(F&M)
prostrate knotweed, renouée des oiseaux
prostrate knotweed, renouée des oiseaux
(close up)
prostrate knotweed, renouée des oiseaux
prostrate knotweed, renouée des oiseaux
(between sidewalk and lawn)
prostrate knotweed, renouée des oiseaux
(between sidewalk and road)
wild buckwheat, renouée liseron
(F&M)
wild buckwheat, renouée liseron
wild buckwheat, renouée liseron
(seedling, FF)
wild buckwheat, renouée liseron
(vegetative, FF)
wild buckwheat, renouée liseron (NC) Japanese knotweed, renouée du Japon
(flowering plant)
Japanese knotweed, renouée du Japon
(young plant)
Japanese knotweed, renouée du Japon
Japanese knotweed, renouée du Japon pale smartweed, persicaire pâle
pale smartweed, persicaire pâle (NC) lady's-thumb, renouée persicaire
lady's-thumb, renouée persicaire
(seedling, FF)
green smartweed, renouée scabre and lady's-thumb, renouée persicaire
(F&M)
green smartweed, renouée scabre green smartweed, renouée scabre
(2 seedlings)
sheep sorrel, petite oseille
(F&M)
sheep sorrel, petite oseille
sheep sorrel, petite oseille
(3 seedlings, FF)
sheep sorrel, petite oseille (NC)
curled dock, patience crépue curled dock, patience crépue (NC)
long-leaved dock, patience à feuilles longues long-leaved dock (upper left); field dock (upper right); serrate-valved dock (lower left); broad-leaved dock (lower right).
A, basal leaf; B, seed; C, valve. (from C. Frankton and G. A, Mulligan 1987, Weeds of Canada, Publication 948, Agriculture Canada, Ottawa, Ontario, 217 pp.).