Botanical Name: Symphyotrichum laeve
Common Name: Smooth Aster, Smooth Blue Aster
Description: According to the Atlas of Florida Plants, there are 28 species of Symphyotrichum asters native to Florida. So be sure to choose by the color, height, sun/shade, and spreading capabilities of each plant to get the perfect selection for your garden.
Symphyotrichum laeve is a unique Florida native aster with many qualities making it an ideal selection for home gardens. The flowers can range from pale blue to vibrant purple, with yellow centers that change to red over time. Rather than the shrubby habit of other asters, Smooth Aster grows up to 4’ tall on narrow stalks with smooth blue-green leaves, sturdy and resistant to high winds and persist after flowering. The leaves can change to vibrant fall colors as well, although the bloom period can be long lasting, beginning in August and continuing through October. Although it can spread by rhizomes, this species of aster grows slowly and pairs well with other garden plants, especially in an open landscape. It flowers best in sun or part sun but can tolerate part shade, as well as a range of soils from moist to dry. One of the most attractive blue asters, this species has bright green foliage that is very smooth to the touch. Is drought resistant. Is not deer resistant. Its native habitat is prairies, dry open woods, roadside banks, and thickets.
It is usually unbranched below, while branching occasionally above. The stems are light green or light blue, glabrous, and often glaucous; they are usually terete, although sometimes the stems are narrowly furrowed. Alternate leaves occur along the entire length of these stems, becoming gradually smaller in size as they ascend. These leaves are up to 6″ long and 1¼” across, although they are typically about one-half of this size. The leaves are oblong-ovate, oblong-obovate, lanceolate, or ovate in shape, while their margins are either entire (toothless) or sparingly and bluntly toothed. Both lower and upper leaves clasp their stems. The upper leaf surface is medium green to grayish blue, glabrous, and sometimes glaucous, while the lower leaf surface is light green or light grayish blue, glabrous, and sometimes glaucous. A reticulated network of secondary veins is usually visible on the lower surface of each leaf.
The central stem terminates in a panicle of flowerheads about ½–1′ long and about one-half as much across; smaller panicles of flowers often develop from lateral upper stems and the axils of upper leaves. Each flowerhead is ½–1″ across, consisting of 15-30 ray florets that surround a dense head of numerous disk florets. The petaloid rays of the flowerheads are light lavender or light blue-violet (rarely white), widely spreading, and narrowly oblong in shape. The corollas of the disk florets are 3-6 mm. long, tubular in shape, and 5-lobed along their upper rims. During the blooming period, they change in color from whitish yellow to purplish red, eventually turning brown afterwards. The short-triangular lobes of these corollas are erect or ascending. Surrounding the base of each flowerhead, there are glabrous phyllaries (floral bracts) in several series that are erect or appressed together; they are linear-oblong in shape or sometimes wider. These phyllaries are mostly light green or light bluish green; they have either dark green markings at their tips or solitary vertical veins that are dark green.
Has special value to native bees. Attracts bumblebees, leaf-cutting bees, metallic bees, honey bees, butterflies, moths, syrphid flies, wasps, beetles. Gives wildlife cover and food to Bobwhites, Songbirds, Thrushes, Turkeys, Wood Warblers, numerous insect herbivores including the walking stick Manomera blatchleyi. Is host plant for the Pearl Crescent butterfly and the Wavy-Lined Emerald moth.
I’m not finding a lot of salt tolerance info on this aster. If you have personal experience growing this on the coast, please let me know. In the meanwhile, I’m going to list it as moderately tolerant of salty winds. No tolerance to salt/brackish water inundation or salt spray.
This plant in 1-gallon containers is 8-15″ tall.
Plant Lore: This gets its common name and specific epithet, Smooth Aster, because it has smooth leaves and stems, unlike other asters that have trichomes (little hairs) on their stems and leaves. Genus name comes from the Greek symph meaning coming together.
Florida Hardiness Zones 8 – 9