WSU Extension

Hortsense

Weeds : Prickly lettuce (China lettuce) : Lactuca serriola
(revision date: 4/7/2021)

Family: Asteraceae (Compositae)
Cycle: Annual/Biennial
Plant Type: Broadleaf
Use Integrated Pest Management (IPM) for successful weed management.

Biology
Prickly lettuce grows from one to five feet tall from a large taproot. The sap is milky. Seedling plants have slightly lobed leaves with spines on the back of the light-colored midvein. On more mature plants, leaves are alternate with spines or prickles both on the leaf margins and beneath the midvein. Upper leaves are frequently deeply lobed, while lower leaves may be without lobes. Leaves partially surround the stem at the base of the leaf (clasping). Branching typically occurs only in the flowering portion of the plant, where numerous 1/8- to 1/3-inch-wide, pale yellow flower heads are produced on stalks from leaf axils. Petals often turn blue as they dry. Flowers are followed by dandelion-like fuzzballs of plumed seeds. SPECIAL INFORMATION: Young growth is reported to be somewhat toxic to cattle, horses, and sheep.
Habitat
Prickly lettuce is common in waste places and disturbed sites such as roadsides, yards, gardens, and irrigated crops, often on light or dry soils. It is not usually a problem in maintained lawn and turfgrass.

Management Options

Non-Chemical Management
  • Maintaining a healthy planting or turf area to provide competition will prevent weed establishment.
  • Cultivation (rototilling or hoeing) will effectively eliminate plants.
  • Hand-pull to eliminate weeds.
  • Mowing to prevent seed production is a very effective means of management. In lawns, mowing regularly at the proper height for the grass species may help minimize weed growth and invasion.
  • Careful digging is useful to manage weed populations. However, digging can carry undesirable weed seed to the surface and foster further germination.
Select non-chemical management options as your first choice!

Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Apply according to label directions. Glyphosate products should be applied as spot treatments only! NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas
  • glyphosate
  • products containing triclopyr
  • products containing 2,4-D
Turf areas
  • products containing 2,4-D
  • products containing MCPA
  • triclopyr
Bare ground areas
  • glyphosate
  • triclopyr
  • products containing 2,4-D
Images
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Caption: Prickly lettuce leaves
Photo by: R. Parker
Caption: Prickly lettuce flower
Photo by: D.G. Swan
Caption: Milky fluid exuding from prickly lettuce cut stem
Photo by: D.G. Swan
Caption: Prickly lettuce flower
Photo by: T.W. Miller
Caption: Prickly lettuce prickles
Photo by: T.W. Miller
Caption: Prickly lettuce flower stalks
Photo by: R. Parker
Caption: Prickly lettuce
Photo by: J.A. Kropf