Invasive Species: Lactuca serriola, Prickly Lettuce
Prickly lettuce is an invasive annual or biennial that can reach heights of 6 ft. (1.8m). Cauline leaves (on the stem) are alternate, 2 to 14 in. (5 to 36 cm) long; they become smaller up the stem. Leaves have a conspicuous, white midvein with the underside of the vein covered with many prickles. In the mid-to-late summer, yellow flowers that are 1/2 in. (1.3 cm) wide develop in a branched inflorescence at the apex of the stem. Flowers produce dandelion-like seeds. Prickly lettuce is native to the Mediterranean region and occurs along roadsides, in abandoned fields, and other disturbed areas. It was accidentally introduced into North America in the late 1890s, possibly as a contaminant in seed.
What are invasive species and why should we be concerned about them?
Taxonomy: Scientific and Common Names for This Species
Asterales > Asteraceae > Lactuca serriola L.
Synonym(s): China lettuce, wild lettuce
Lactuca serriola – USDA PLANTS Profile
Distribution Maps
Prickly lettuce – The reported distribution of this invasive species across the United States. (Source: Invasive Plant Atlas of the United States)
Up-to-the-minute distribution maps and why they are important.
Reporting This Invasive Species
What is the best way and place to report the occurrence of an invasive species?
How to report an invasive species sighting to EDDMapS – Early Detection & Distribution Mapping System
EDDMapS – Report an invasive species to EDDMapS
Cooperative Extension Offices – Find your local Cooperative Extension office on this map provided by USDA
How to Identify
This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.
Plant
Prickly lettuce is an invasive annual or biennial that can reach heights of 6 ft. (1.8m).
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| Forest & Kim Starr, Starr Environmental, bugwood.org | Steve Dewey, Utah State University, bugwood.org |
Foliage
Cauline leaves (on the stem) are alternate, 2 to 14 in. (5 to 36 cm) long; they become smaller up the stem. Leaves have a conspicuous, white midvein with the underside of the vein covered with many prickles.
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| Tom Heutte, USDA Forest Service, bugwood.org | Steve Dewey, Utah State University, bugwood.org |
Flower
In the mid-to-late summer, yellow flowers that are 1/2 in. (1.3 cm) wide develop in a branched inflorescence at the apex of the stem.
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| Mary Ellen (Mel) Harte, bugwood.org | Mary Ellen (Mel) Harte, bugwood.org |
Fruit
Flowers produce dandelion-like seeds.
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| Ken Chamberlain, Ohio State University, bugwood.org | Steve Hurst, USDA NRCS PLANTS Database, bugwood.org |
Native Species That Resemble Prickly Lettuce
There are native species of Lactuca across the continental United States, including Alaska.
Lactuca canadensis, Canada lettuce – Images at invasive.org
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| Mary Ellen (Mel) Harte, bugwood.org | Mary Ellen (Mel) Harte, bugwood.org |
| Lactuca floridana, Florida wild lettuce – Images at invasive.org |
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| Dan Tenaglia, Missouriplants.com, bugwood.org | Dan Tenaglia, Missouriplants.com, bugwood.org |
Additional Images for Prickly Lettuce
Prickly lettuce – Images at Invasive.org
Learning Resources for Prickly Lettuce
Additional Information, Biology, Control and Management Resources
Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state’s land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.
United States Land-Grant University System – Find your land-grant university’s College of Agriculture, Cooperative Extension Service, or other related partner on this map provided by USDA.
Jepson Herbarium – University of California
Weed Guide – Virginia Tech Weed Identification Guide
Prickly Lettuce, China Lettuce – Lactuca serriola – Wildflowers of the United States
Prickly Lettuce – Illinois Wildflowers