Species Native to Missouri
Common Name: lettuce
Type: Annual
Family: Asteraceae
Native Range: United States
Height: 2.00 to 7.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: July to October
Bloom Description: Pale blue
Sun: Part shade to full shade
Water: Medium to wet
Maintenance: Medium
Suggested Use: Annual, Vegetable
Flower: Showy
Tolerate: Wet Soil
Culture
Annual/biennial that is best grown in moist to wet soils in part shade to full shade. Needs constant moisture. Remains in the wild by self-seeding.
Noteworthy Characteristics
Lactuca floridana, commonly called Florida blue lettuce or wild lettuce, is an annual/biennial that typically grows to 2-7’ tall. It is native to moist to wet open woods, thickets, disturbed sites, waste ground, streambanks, roadsides and railroads in North America from Manitoba and Ontario south through New York to Florida and through South Dakota to Texas. Although related to Latuca sativa (edible lettuce of salads), this woodland lettuce has a bitter flavor and is not commonly eaten. Young basal leaves may be added raw to salads. Older leaves may be cooked as greens.
Deeply-lobed, pinnately veined, lanceolate to triangular, dandelion-like, basal leaves (to 3-10” long and 1-4” wide) have pointed tips, toothed margins and tapered bases. Smaller upper leaves are lanceolate. Leafy purplish stems to 7’ tall rise from the basal clump in spring topped by large branching inflorescences of pale blue flowers (hence the common name of Florida blue lettuce) which bloom, only several at a time, from July to October. Each inflorescence is in the form of a loose panicle of 11-17 flowers (each to 1/2” across) featuring small, petal-like, pale blue (sometimes close to white) rays with no center disks. Flowers give way to flattened short-beaked achenes featuring white fluffy bristles (pappus). Plants will secrete a milky sap if bruised or cut.
Genus name comes from the Latin word lac meaning milk in obvious reference to the milky plant sap.
Specific epithet means of Florida.
Problems
No serious insect or disease problems. Potential disease problems include downy mildew, powdery mildew, shot hole, bottom rot, septoria leaf spot, Botrytis and wilt. Potential insect pests include aphids, snails, slugs, leafminers and whiteflies. Mosiac virus may appear.
Uses
Somewhat weedy annual/biennial with limited ornamental value. Best grown in moist shady areas. May be grown in vegetable gardens.