American Wild Lettuce (Lactuca canadensis)
Updated June 15th, 2026A tall biennial native to eastern North America, having expanded its range westward as well.
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A tall biennial native to eastern North America, having expanded its range westward as well.

An herbaceous perennial, native to Europe, which spreads aggressively, forming large colonies, by underground rhizomes. Escaped from cultivation at various locations across North America, mostly in the northeast, where it is considered invasive.

A perennial spring ephemeral native to Europe through Western Asia, invasive in North America, occurring in moist bottomlands where it often escaped from lawns and gardens.

An interior region of the Appalachians reaching to higher elevations than areas to the east and west; mostly forested.

A mountain range in North Carolina, geologically part of the Blue Ridge, yet isolated within the piedmont.

A unique region with sandy surface soils and glacier-disrupted drainage, with largely-undisturbed prairies.

These species are visually similar and are easily confused. The confusion is worsened by nurseries mislabeling P. filiformis as P. virginiana. They can be distinguished by leaf shape, chevron pattern, and flower color. Some plants are cultivars that are easily identifiable as P. filiformis, but wild-type plants warrant closer examination. P. filiformis is less common throughout, but mostly found in the same range and similar habitats to P. virginiana.

These species are easily confused in the limited zone in which their ranges overlap. They can usually be distinguished by differences in flower size and seeds. They have differences in leaf shape and bloom time, but with some overlap in both characteristics. Both tend to grow in partly-shaded, moist, disturbed habitats in rich soils, and for the most part, L. biennis is the more northerly species occupying a similar niche as L. floridana, the more southerly species, but L. floridana ranges farther north in the central US, and L. biennis is also found in the West. Where they overlap, L. floridana tends to prefer shadier, moister, and slightly less disturbed habitats than L. biennis.

These two species are visually similar and have significant range overlap in eastern Canada and the north and central US. Vining plants or ones with aerial rootlets are easily identified as T. radicans, which averages hairier and with slightly larger fruit. T. radicans ranges farther southeast, to lower elevations, and into shadier habitats, and is found in a wide range of moisture conditions and soil pH. T. rydbergii ranges farther west and north, is more restricted to higher elevations and open habitats. In the overlap zone, T. rydbergii prefers rocky, usually acidic soils and drier conditions, although deeper in the arid west it is restricted to richer soil in ravines and canyons.







