Monday, May 24, 2021

Woodland lettuce - Lactuca floridana

Woodland lettuce (Lactuca floridana) is an annual or biennial native to disturbed somewhat shady moist habitats throughout most of Florida. It is also widespread across much of the eastern and central US, as well as the Canadian provinces of Ontario and Manitoba.  Though widespread here in Florida, this species and its close relatives are rarely included in wildflower guide books. Why that is so seems a mystery to me.

Lactuca is the genus that includes the edible lettuces of our salads, but the leaves of this species are bitter and are best eaten only after a thorough soaking in water for some time. The genus name is derived from the milky sap produced by most of this genus and woodland lettuce is no exception.  When in doubt as to whether this is actually wild lettuce, pick a piece off of a leaf and look for the white sticky sap that will emerge.

This species emerges from the seed bank in early spring and grows quickly to a mature height of about 4-6 feet. 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 other 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). 

Woodland lettuce is not likely to ever be purposely grown as an ornamental by any of the native plant nurseries due to its short-lived nature and limited aesthetics. The small attractive compound flowers are visited by pollinators, however, and the greens can be used in much the same way that dandelions (Taraxacum officinale) are further north. If you desire this plant in your landscape, it is easily grown from seed. Plant it in partial shade in a location that retains some moisture.

Starry Rosinweed - Silphium asteriscus

The Asteraceae includes some of the very best plants for home landscapes dedicated to providing nectar and pollen for pollinators. This includes the rosinweeds of which starry rosinweed (Silphium asteriscus) is one of two native to Florida. Although the Midwestern prairies of my youth contain a great many species, most disappear as you go south. Kidney-leaf rosinweed (S. asteriscus) only makes it to central Florida in well-drained uplands. Starry rosinweed is found nearly statewide, but naturally only on the west coast, from the top of the Panhandle to Lee County in the south. In this region, it occurs primarily in open, slightly moist habitats.

Rosinweeds are perennials that die back to the ground in winter, though starry rosinweed does this much later in the fall than its close cousin. The basal leaves that emerge in spring are 6-10 inches long, several inches wide and extremely scabrous. Unlike its close cousin, the leaves are elliptical, unlobed and toothed along the leaf margins.  Growth occurs quickly in the spring and the stems reach 2-3 feet tall by April. Multiple flower heads occur at the end of these stems and flowering can occur into November. Each compound flower is surrounded by 1-2 dozen bright yellow ray petals and these surround the disk flowers that also are yellow. These, like other "sunflowers", open sequentially over 1-2 weeks. Unlike most asters, the disk flowers do not produce seed. Only the ray petals do.

Rosinweeds attract a great diversity of pollinators and are nearly always being visited by something during the day. Though kidney-leaf rosinweed is quite touchy regarding its growing conditions, starry rosinweed is quite adaptable and can be grown in nearly any condition found in a typical landscape setting. Because of this, it has become one of the most commonly grown native wildflowers in Florida and can be procured at nearly every native plant nursery affiliated with FANN - the Florida Association of Native Nurseries.  It will adapt to drier soils than it naturally occurs in, but water it well until fully established if you can't give it seasonably moist conditions. It grows easily from seed, collected when it is brown and dry, and it will regularly self seed in most landscapes.