Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Broad-leaved dock

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Leaves
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Broad-leaved dock, Rumex obtusifolius L.,

Other Names: patience à feuilles obtuses, Bitter dock, Blunt-leaved dock, Red-veined dock, rumex à feuilles obtuses, rumex sanguin

Family: Buckwheat or Smartweed Family (Polygonaceae)

General Description: Perennial, reproducing only by seed. Very similar to Curled dock but cotyledons (seed leaves) 1/3 as wide as long.

Photos and Pictures

Broad-leaved dock. Seedling in 3rd true-leaf stage. B. Lower portion of leafy stem. C. Young inflorescence. D. Single, 3-wnged "fruit".

Leaves: First few true leaves either round in outline or with heart-shaped bases; rosette and stem leaves broad with rounded or more usually heart-shaped bases; their margins flat or somewhat wavy up and down but never strongly curled or wavy-margined; veins green or somewhat reddish, prominent and somewhat white-hairy on the undersurface; ocrea (membranous sheath) surrounding stem above each node, up to 5 cm (2 in.) long, becoming brown and papery with age.

Flowers & Fruit: Inflorescence similar to but thicker than Curled dock; the 3 wing-like inner sepals of each "fruit" with several irregular teeth along the margins, but only 1 of the 3 sepals bearing a prominent egg-shaped corky enlargement (tubercle) on its back. Flowers from June to July.

Habitat: Broad-leaved dock occurs in moist situations throughout southern Ontario but is seen only scarcely in the north and northwest. It occurs along streams, meadows, wet roadside ditches, moist waste areas, and in depressional areas in cultivated land.

Similar Species: It is distinguished from similar plants by its broad leaves with heart-shaped bases and the prominently toothed margins of the 3 wing-like sepals (valves) of the fruit, only 1 of which usually develops an enlarged, egg-shaped corky or fleshy tubercle on its outer surface.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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