Prickly lettuce is a winter annual. The leaves form in a basal rosette. Prickly lettuce has a deep taproot which will exude a milky sap. Prickly lettuce will produce an upright stem on which the leaves will be alternate. The mature leaves are deeply lobed. The leaves will twist vertical to the stem. The leaves have a row of spines along the mid-vein of the lower surface. The flowers of prickly lettuce are yellow in color and approximately 1/3” in diameter. Flowers are produced in late spring to early summer. Prickly lettuce reproduces by seed. Prickly lettuce is found throughout most of the United States and Canada except southern Florida, northern Maine and Newfoundland.
Prickly lettuce is usually found in disturbed sites. It does best in thin low-maintenance turf. It produces an erect stem that will be removed by mowing. It prefers soils that are irrigated and higher in nutrients. It can be a problem in container grown ornamentals and be introduces into landscape beds and turf areas.
For optimum control, apply your post-emergence herbicide to prickly lettuce that is actively growing and in the seedling to flower stage of growth.