Lactuca biennis
tall blue lettuce
Overview
Lactuca biennis is a tall biennial that forms a leafy rosette in its first year and a stout, erect flowering stem 3-15 ft (0.9-4.5 m) tall in its second. The hollow, smooth stem and the leaves exude a milky white sap when cut. Leaves are large, 4-12 in (10-30 cm) long, pinnately lobed with a winged stalk, and clasp the stem at the base. In summer to fall the top of the stem opens into a broad, branched cluster of many small flower heads, each 0.2-0.3 in (5-8 mm) across with several pale blue to creamy-white ray florets. The heads give way to seed tipped with tan to brownish bristles that carry it on the wind. The plant grows in moist woods, thickets, clearings, streambanks, and disturbed openings, often after logging or fire. It completes its life in two years and dies after flowering, so it persists in an area by reseeding. Its height and weedy spread can crowd smaller plants, a limitation in tended beds.
Native Range
Native across much of North America, from Alaska and Canada south through the northern and central United States to the higher Appalachians and the mountain West. It grows in moist woods, thickets, clearings, and disturbed ground.Suggested Uses
Grown in native, woodland-edge, and pollinator plantings and in naturalized wet thickets as a tall background plant. Used in restoration of moist clearings, where it fills quickly and feeds insects and seed-eating birds.How to Identify
Appearance
Size & Dimensions
Height3' - 15'
Width/Spread1' - 3'
Reaches mature size in approximately 2 years
Bloom Information
Detailed Descriptions
Flower Description
pale blue to creamFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight