Prickly lettuce, Lactuca Serriola L., is a weed common to fields, gardens and roadsides. Also known as the compass plant or the china plant, the deeply lobed leaves of this plant lay in a north south direction, perpendicular to the sun. Young prickly lettuce plants are often confused with dandelions, until the plant matures and forms first a centered rosette and later the flower and seed bearing stem. Prickly lettuce stems can grow as tall as 4 to 5 feet. After flowering the seeds are carried on the wind by clinging to the downy, white plumes that surround the seed casings.Prickly lettuce is a milkweed plant. If the stem or root is broken, it will emit a milky substance. The pale yellow flowers appear on the stems in the summer to early fall months, followed by the seed heads.
Prickly lettuce can withstand harsh summers, including drought conditions. The plant prefers well-drained soil and full sun; but it can do well in soils with a high percentage of clay and partial shade. Given free reign, prickly lettuce can take over a garden or a field.
Cultivation and Care
The seed of the prickly lettuce can remain viable for up to three years if winters are mild. After the small yellow flowers have spent, the seed heads split and the seed begins to drop or is carried by the wind to new locations. The seed will begin to germinate immediately if weather conditions are favorable.
Weed Control Techniques
- Hand pulling is the method of choice for young plants. Prickly lettuce has a taproot that if the plant matures will have to be dug using a spade or shovel. Mowing is not recommended as a means of controlling this weed, as the rosette is generally lower than most mower blades and the removal of the stem is not enough to destroy the plant. Using a hoe to break up the rosette, thus impairing the plants ability to form the stem, can hamper plants that cannot be effectively pulled or dug out. Any chemical herbicide developed for broadleaf weeds is effective on prickly lettuce. Follow label instructions carefully to avoid harming surround flower and vegetable plants. Both pre-emergence and post-emergence herbicides are available. Organic methods of control include herbicides that contain clove oil and acetic acid. As with chemical fertilizers, care must be taken to protect surrounding plants. Remove stems before or during the flowering phase to reduce propagation of prickly lettuce. After the harvest is complete, till the area to destroy any remaining plants.* Goats and sheep love prickly lettuce in their diets. They will happily eat an entire field in several weeks time.