Integrated Pest Management

Prickly Lettuce

Lactuca serriola

prickly lettuce

Prickly lettuce (John M. Randall, The Nature Conservancy, Bugwood.org)

prickly lettuce

Prickly lettuce foliage (Ohio State Weed Lab, The Ohio State University, Bugwood.org)

prickly lettuce

Prickly lettuce flowers (Ohio State Weed Lab, The Ohio State University, Bugwood.org)

Description

  • tall (1 – 5 feet); thick stem; branches occur toward top of plant when flowering
  • mature leaves have a wavy appearance with deep lobes attached tightly to the stem
  • the underside of the leaf midrib and stem have prickly hairs, giving the plant a “sticky” feel
  • when broken, the plant exudes a milky substance
  • light yellow flowers give rise to seed clusters with white fluffy plumes that help the seeds float to a new location

Location

  • gardens, cropland and open spaces

Life Cycle

  • biennial or winter annual; reproduces only by seed
  • most seedlings germinate in the fall in a rosette form with a long taproot that overwinters
  • some seedlings emerge in spring
  • stem development and flowering happens mid-summer to late fall, then the plant dies

IPM Recommendations

  • Hand-pull plants in planting beds prior to seed maturation.
  • Maintain healthy, competitive desirable vegetation.
  • Apply an appropriate post-emergent herbicide directly to target weeds.