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Lactuca canadensis
Also called Canada Wild Lettuce, Tall Lettuce, Arrow Leaved Lettuce, Wild Lettuce, Devil's Weed, Tall Wild Lettuce
Canada lettuce is a tall wild lettuce, a biennial in the daisy family that grows from a taproot to 50 to 200 cm, grown mainly as a wild or medicinal herb rather than for salad. It thrives in moist to slightly dry soil in full to partial sun and tolerates poor, disturbed ground.
Lactuca canadensis is a species of wild lettuce known by the common names Canada lettuce, Canada wild lettuce, and tall lettuce. Its true native range is not clear, but it is considered to be a native of the eastern and central parts of North America. It is naturalized in the western part of the continent as well as in Eurasia.
Generally, Lactuca canadensis is a biennial herb in the daisy family growing from a taproot to maximum heights of 50–200 cm (19.5–78.5 in) or more. The leaves are deeply lobed and occasionally toothed. The top of the stem bears an inflorescence with many flower heads, each up to 1 cm (0.5 in) wide when open. The heads have many pale yellow ray florets but no disc florets. The fruit is a dark-colored achene about half a centimeter (0.2 inches) long with a white pappus.
Cultivation preferably is in moist to slightly dry conditions and in full to partial sun. Loamy soil is best for fertility; however, clay-loam and gravely soil are tolerated. Size depends on growing conditions.
It occurs across the continental United States, except for Nevada and Arizona, and across most provinces in Canada. It is found commonly in all counties in Illinois.
Lactuca canadensis contains lactucarium, which is the milky sap (white latex) that flows through the stem, leaves, and roots of the plant. It is used as a medicinal herb when dried after contact with air. A survivalist publication, The Lost Ways, states that its fresh leaves may be used to create a solution that may act as an analgesic and may be stored for later use. It may be used as medicinal treatments for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic, and sedative properties. Concentrations of lactucarium are low in young plants, but increase in older plants, occurring highest when in blooming period. Sap may be applied to skin in use for treatment of external warts. It is said to be a relaxing and sedative herb that is used to induce sleepiness, and to calm restlessness and anxiety. Although the standard definition of lactucarium requires its production from Lactuca virosa, it was recognized that smaller quantities of lactucarium could be produced in a similar way from Lactuca sativa and Lactuca canadensis var.
Tall blue lettuce · Indian lettuce · Willowleaf lettuce · Celtuce · Iceberg lettuce · Romaine lettuce · Lettuce · Prickly lettuce · Bitter lettuce · Lettuce
Text excerpted from the Wikipedia article Lactuca canadensis by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
