Rumex obtusifolius, commonly known as broad-leaved dock, bitter dock, bluntleaf dock, dock leaf or butter dock, is a perennial weed, native to Europe but can now be found in the United States and many other countries around the world.
The non-native Bitter Dock is a fairly common plant that occurs in the majority of counties in Illinois; it is least common in the NW and north central areas of the state (see Distribution Map). Habitats include moist woodland edges, seeps, semi-shaded areas along streams, gardens and edges of yards, areas along buildings, vacant lots, roadside ditches, and waste areas. Bitter Dock is native to Eurasia and prefers disturbed areas. Faunal Associations
Plants perennial, glabrous or ± papillose especially on veins of leaf blades abaxially, with fusi-form, vertical rootstock. Stems erect, branched distal to middle or occasionally in distal 2/ 3, often with few flowering stems from rootstock, 60-120(-150) cm. Leaves: ocrea deciduous to partially persistent at maturity; blade oblong to ovate-oblong, sometimes broadly ovate, 20-40 × 10-15 cm, usually less than 4 times as long as wide, base normally distinctly cordate, occasionally rounded, rarely truncate, margins normally entire, flat or undulate, rarely slightly crisped, apex obtuse or subacute. Inflorescences terminal, occupying distal 2/ 3 of stem, usually lax and interrupted, narrowly or broadly paniculate, branches usually forming angle of 30-45° with 1st-order stem. Pedicels articulated in proximal 1/3 or rarely near middle, filiform, 2.5-8.5(-10) mm, articulation distinctly swollen. Flowers 10-25 in lax whorls; inner tepals ovate-triangular, deltoid or, occasionally, lingulate, 3-6 × 2-3.5 mm (excluding teeth), ca. 1.5-2 times as long as wide, base truncate, margins usually distinctly dentate, rarely subentire, apex obtuse to subacute, straight, teeth 2-5, normally at each side of margin, short-subulate or triangular-subulate, straight, 0.5-1.8 mm, or shorter than width of inner tepals; tubercle usually 1, sometimes 3, then 1 distinctly larger, smooth. Achenes brown to reddish brown, 2-2.7 × 1.2-1.7 mm. 2n = 40.
Rumexobtusifolius subsp. agrestis (Fries) Danser; R. obtusifolius var. agrestis Fries.
The non-native Bitter Dock is a fairly common plant that occurs in the majority of counties in Illinois; it is least common in the NW and north central areas of the state (see Distribution Map). Habitats include moist woodland edges, seeps, semi-shaded areas along streams, gardens and edges of yards, areas along buildings, vacant lots, roadside ditches, and waste areas. Bitter Dock is native to Eurasia and prefers disturbed areas. Faunal Associations
Bitter Dock is one of the more ornamental species of Docks. It is fairly easy to distinguish from other Docks by its shiny leaves, which are rather broad, well-rounded or cordate at the base, and crisped along their margins. Another distinctive characteristic is the appearance of the calyx, which has spiny teeth along its margins. Another common name for this species is Broad-Leaved Dock.