Lactuca serriola, Prickly Lettuce


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).

prickly lettuce prickly lettuce
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.

prickly lettuce prickly lettuce
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.

Prickly Lettuce Prickly Lettuce
Mary Ellen (Mel) Harte, bugwood.org Mary Ellen (Mel) Harte,  bugwood.org

Fruit

Flowers produce dandelion-like seeds.

Prickly Lettuce Prickly Lettuce
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

tall lettuce tall lettuce  Lactuca canadensis
Mary Ellen (Mel) Harte, bugwood.org Mary Ellen (Mel) Harte, bugwood.org
 
Lactuca floridana, Florida wild lettuce – Images at invasive.org  
Florida wild lettuce Florida wild lettuce
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