The flowers of prickly lettuce are yellow in color and approximately one-third of an inch in diameter. Flowers are produced in late spring to early summer. Individual plants can produce from 35 to 2,300 flowers. Each flower head contains an average of 20 seeds, giving an estimated seed production of 700 and 46,000 seeds per plant, respectively. Most seeds are viable and ready to germinate immediately after dispersal and can germinate within the top centimeter of soil after the smallest of rain events. Prickly lettuce forms only a short-term seed bank, with seeds surviving 1–3 yr in soil. Prickly lettuce (Lactuca serriola
) seeds travel with the help of their downy, white plumes. Prickly lettuce is most commonly a weed of nurseries, orchards, roadsides, and agronomic crops and is found throughout the United States.
Prickly lettuce is drought tolerant and can have detrimental effects on crop value and harvesting efficiency of wheat. The flower buds can be difficult to screen out of grain, resulting in discounted prices. The sticky white latex in the stems can clog harvesting equipment and raise the moisture content of the grain.
Hand pulling: Hand pulling is effective for small infestations if it’s done when the ground is moist.