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Symphyotrichum Asters for the Home Landscape Part 2: The Less Aggressive Asters
Article and photos by Craig Huegel, PhD
In the previous article (Palmetto 40.2), I wrote about Symphyotrichum asters in general and covered the species that are most aggressive in my Pasco County landscape. The asters in this article are less aggressive, but all asters spread when grown in the proper conditions. They spread by seed, but more commonly by underground stems known as rhizomes. Given time, all asters will produce plantlets off these rhizomes and form colonies. In a small mixed landscape where maximum diversity is desired, these less aggressive asters will require less thinning out to keep them from overwhelming their neighbors.
Scaleleaf aster (Symphyotrichum adnatum)
Scaleleaf aster is easy to identify. As its common and Latin names imply, it is characterized by tiny scalelike leaves that are appressed along its wiry stems. It is common to most of Florida from the Panhandle south to the Florida Keys although it has not been vouchered in northern peninsular parts of the state and in much of the eastern half of the southern peninsula. Outside of Florida, it occurs in the southern Southeastern Coastal Plain from Georgia west to Louisiana. Throughout its distribution, it grows in open sandy habitats. My first experience with it was in xeric flatwoods, but it also is found in sandhills.
Scaleleaf aster is barely noticeable when it emerges in the spring. Its whipcord stems are only partly erect and they tend to get lost in adjacent vegetation. The stems are 2-4 feet long, but rarely more than 2 feet tall unless well supported by the surrounding vegetation. Multiple stems are produced off the main stem and are covered by short, noticeable hairs. The basal leaves are lost early in the growing season, leaving only the yellowish green shiny scalelike leaves from summer to early winter. In my landscape, scaleleaf aster is the last to bloom, often waiting until December. The flowers are composed of lavender ray flowers surrounding a yellow disk and are about ½ inch across. Because it blooms so late, it is an important nectar source for the few pollinators that are still active.
Chapman’s aster (Symphyotrichum chapmanii)
Chapman’s aster is one of my favorites, but I’ve never had much success with it in my home landscape. It is common to the wet savannas and freshwater marsh edges of the western Panhandle, but has also been reported in Alachua and St. Lucie Counties, well outside its primary range. It also is a near endemic, being vouchered outside Florida only in Georgia. Chapman’s aster can go largely unnoticed when not in bloom. It produces a basal rosette of very thin deep green linear leaves in spring and then a single flowering stalk that eventually reaches about 3 feet in height. The leaves remain linear but are much reduced in size as they ascend the stem.
Flowers are produced singly atop the main stem or on a few side stems in late summer to very early fall, and it is one of the first asters to bloom each year in my landscape. The flowers are comprised of numerous very thin rich lavender ray flowers surrounding a yellow disk. They are very attractive, but far more striking when seen in mass. Chapman’s aster would be a good candidate for a mixed-species planting in a wetland setting.
Silver aster (Symphyotrichum concolor)
Silver aster produces many willowy stems from a basal clump of linear leaves covered with white felty hairs. As in many asters, the ½ to 1-inch-long basal leaves disappear soon after the main stems are produced. The narrow leaves are much reduced along the stem, becoming no longer than ¼ inch near the top of the flowering stalk. They are tightly clasping but the t ips are everted outwards.
In my landscape and in natural areas nearby flowers appear in late October and well into November. They differ from many in this genus by their color. The elliptical ray flowers are a cornflower blue and they surround a grayish white central disk that turns reddish as it ages. Flowers are produced in a panicle atop the main stem. Silver aster occurs throughout much of Florida in welldrained sandy habitats, and throughout much of eastern North America as far north as New York. This species is infrequently offered commercially in Florida by native plant nurseries and should be more widely propagated.
Georgia aster (Symphyotrichum georginanum)
Georgia aster is a beautiful species that is extremely rare throughout its very limited range. In Florida, it is only reported from Leon County and is scattered in a few localities in Georgia, Alabama and the Carolinas. It occurs in well-drained open habitats. Despite its rare natural distribution, Georgia aster is often offered for sale by native plant nurseries. This species produces large elliptical basal leaves with pointed tips. They may be up to 6 inches long and more than 1 inch wide, thick and rough to the touch due to stiff hairs, and with revolute edges. These leaves do not become much smaller as they ascend the single flower stalk. The somewhat woody stalks reach a mature height of 3 feet by late summer.
Flowers are produced in open panicles atop the main stem in mid-fall and are quite showy due to their size and color. The thin ray flowers are a unique deep cornflower blue and they surround a center of white disk flowers that turn reddish as they age. Georgia aster has been easy for me to propagate from seed, but the mature plants do not persist long in my landscape. I find that it does best when not crowded by other plants.
Smooth blue aster (Symphyotrichum laeve)
Smooth blue aster is a rare species in Florida, but it is extremely common to our north. Though it is vouchered here only from Jackson County, it occurs in virtually every state and province throughout North America including the Yukon in extreme northwestern Canada. This species is most commonly found in upland openings in a wide variety of habitats. Because of its extensive geographical range, 4 distinct varieties are recognized. Ours is considered var. concinnum and it is found throughout the Southeastern Coastal Plain, north to Pennsylvania. A major characteristic that distinguishes our variety from the others is that the basal leaves wither and are lost prior to blooming. The leaves are smooth, lacking the hairs found on many other asters. They are rich green in color, rather thick, 1-2 inches long, and without teeth along the margins. Flowering stalks are produced by summer and reach a mature height of about 2-3 feet. Many ½ to 1-inch flowers are produced in an open panicle atop these stems. Numerous thin ray flowers are violet to blue in color and surround the central yellow disk flowers. This aster blooms in early September through late fall, but often is finished before other aster species in my landscape. I have grown this species for several years and found it easy to grow, but I have never seen it offered by Florida native nurseries.
Sky-blue aster (Symphyotrichum oolentangiense)
There is some disagreement among taxonomists as to whether this aster species is native or introduced. It is vouchered from 4 counties in the central Panhandle and these include at least 1 location that I personally know of t hat is not near a created planting. There is no question regarding its nativity north of
Florida, and it is found in most states in the eastern half of the U.S. and in Ontario. Throughout this extensive range, it most often grows in sunny well-drained habitats. The species name comes from the site location in Ohio where it was originally described – the Oolentangy River. Skyblue aster may produce up to 5 stems from its central basal cluster in the spring. These are thin and normally glabrous, but sometimes have sparse short hairs. While the lower leaves are up to 3 inches long and 1 ½ inches wide, they become somewhat smaller as they ascend the stems. The deep-green leaves are oblong in shape and shiny on their upper surface while the lower surfaces are light green and often have noticeable short hairs along the major veins. The leaf margins are entire or with a few shallow teeth.
Sky-blue aster blooms in late summer to mid-fall, and the flowers form in loose panicles atop stems 2-3 feet tall. Large numbers of azure blue to lavender flowers are produced. Each bloom is about ½ inch across and consists of up to 2 dozen broadly linear ray flowers surrounding a central yellow disk. This species is easy to grow from seed, but it is not currently available f rom nurseries in Florida as far as I am aware.
Late purple aster (Symphyotrichum patens)
Few of our native asters can match the rich flower color of late purple aster, and it is a shame that this species is not regularly propagated in Florida. It is vouchered in scattered locations in 6 counties across North Florida, but has a wide distribution outside of our state and occurs in most of the eastern two-thirds of the U.S. It does best in open sunny locations with well-drained to average soils. It also is reported to have some salt tolerance, though I have not grown it under those conditions. It produces multiple thin stems that can reach 2-3 feet at maturity, but often arch over under their own weight and never become that tall. The leaves are rather thick and stiff with undulating margins, and the leaf shape is somewhat spatulate to oval with pointed tips and with stiff hairs. They quickly decrease in size as they proceed up the stems and the 2.5-inch basal leaves are lost early – well before blooming.
In my landscape, late purple aster is generally finished blooming by mid-November and before a few other asters are done. Many ½-inch wide flowers are produced atop the main stalk and numerous side stems. They are comprised of up to 2 dozen rich lavender ray flowers surrounding a central set of disk flowers that vary from yellow to cream in color. Three varieties of late purple aster are recognized; ours being var. patens. This is a species that may sucker extensively, but in my landscape, it has been slow to spread.
Plumose aster (Symphyotrichum plumosum)
Plumose aster is an endemic species with a limited geographic range, known only from a region of 8 counties in the central Panhandle. When I first encountered it, I believed it to be silver aster. Only after I got home and looked closely at photos of the phyllaries below the flowers did I recognize what it was. In certain respects, these 2 species share many characteristics and this species has, at times, been considered a variety of silver aster. Plumose aster is found in sunny open habitats with well-drained soils. I’ve encountered it growing in sandhills, though it has been documented in the moister soils of pine flatwoods. It produces a basal rosette of ½-inch linear leaves in spring and these become much reduced and clasping as they ascend the main stem. All of its leaves are densely covered by silvery silky hairs.
Flowering occurs at the tips of the thin wiry stems in fall and on short side stems as well. The small blooms consist of less than 2 dozen cornflower/light lavender ray flowers surrounding a center of white disk flowers which turn reddish as the blooms age. The most distinctive difference between plumose aster and silver aster is the shape and structure of the phyllaries at the base of the bud. In silver aster, these are appressed against the bud while in plumose aster, they are recurved and project outward from the bud. I have been growing this species for several years with good effect in my home landscape and it seems to require very little care.
Barrens silky aster (Symphyotrichum pratense)
At times, barrens silky aster in Florida has been considered a variety of western silver aster (Symphyotrichum sericeum). It is not listed in the online Atlas of Florida Plants, and although many believe it to be a separate species, I will include it under my discussion of western silver aster below. Regardless of its uniqueness taxonomically, its ecology and value in a home landscape are identical.
Western silver aster (Symphyotrichum sericeum)
Western silver aster is vouchered only from Gadsden County in the central Panhandle along the Georgia border, although it is widely distributed in the central portion of the U.S. and parts of Canada. It is variable throughout this geographic region and the Florida form is considered to be var. microphyllum, so-called for its smaller leaves. It is most likely to be encountered in open sunny sites with welldrained soils. Like silver aster, it produces a basal rosette of lanceolate leaves in spring that are densely covered by silvery silky hairs. These leaves are about ½ inch long and become smaller as they ascend the wiry stems. They do not clasp the stems as tightly as in silver aster. These stems reach a mature height of only about 2 feet.
Flowers occur singly or in very small numbers atop the stems in the fall. They are about 1 inch in diameter and composed of up to 2 dozen rich lavender ray flowers surrounding a center of white disk flowers. The phyllaries at the base of the flower buds are similar to the surrounding leaves and are not appressed as they are in silver aster or as outwardly spiky as they are in plumose aster. I have grown this species successfully for several years and it has not suckered extensively, though some reports state that it can. If you grow this species in your landscape, make sure not to crowd it.
Short’s aster (Symphyotrichum shortii)
I have grown Short’s aster for several years and admire it greatly. In Florida, it is only reported from Jackson and Gadsden Counties in the central Panhandle near the Georgia border, but it is widely distributed to our north and west; occurring in most states in the eastern half of the U.S. and in Ontario. Throughout this range, it is reported to prefer moist, well-drained soils and partial shade, though the specimens I planted several years ago in part shade fared much poorer than those that received more sun. This is a relatively easy species to identify by foliage as it has distinctly cordate (heart-shaped) leaves that can be 6 inches long and several inches across. The basal leaves may have toothed margins, but these teeth disappear along the stems though they do not decrease much in size. The upper surface of each leaf is a rich green and glabrous, but the lower surface is much lighter in color and sparsely pubescent with hairs along the midvein and a reticulated network of secondary veins. The stout main stem arises from the basal leaf cluster in spring and eventually reaches a mature height of about 3 feet.
Large numbers of flowers are produced at the top of these stems and on numerous side stems in fall. The number of blooms and their size often causes the flower stalks to bend over. Each flower is about 1 inch across and composed of about 15 somewhat wide light lavender ray flowers and a central disk of pale yellow flowers. This is an especially beautiful and pollinator useful species when in full bloom.
Wavyleaf aster (Symphyotrichum undulatum)
I have grown wavyleaf aster for several years and it is one of just a few that reseeds each year well outside of where it was planted. To me, that indicates its resilience in a home landscape setting. In Florida, this species is reported from much of t he Panhandle and the northern peninsular counties. It also occurs in nearly every state east of the Mississippi River and from Ontario. In this range, it is common to a wide variety of sunny habitats with well-drained soil, though my experience suggests it to be adaptable to soils that are a bit moister. This species is characterized by having narrow willow-like leaves that are glabrous and without teeth on the margins. It produces a single main stem that eventually reaches 3-5 feet tall. The leaves become smaller as they ascend the stem.
Wavyleaf aster tends to bloom a bit earlier than most. Numerous buds are formed at the top of the main stem and a few side branches and they open in late summer to mid-fall. Each bloom is about ½ inch across, composed of about a dozen light lavender ray flowers that surround the central yellow disk flowers.
White arrowleaf aster (Symphyotrichum urophyllum)
I have no personal experience with this aster in the field or in my landscape. White arrowleaf aster is vouchered from 7 contiguous counties in the central Florida Panhandle along the Georgia border. It also occurs in the eastern half of the U.S. and in Ontario. It is reported to occur most frequently in sunny mesic to xeric conditions. The basal leaves are arrow-shaped, about 4½ inches long, have noticeable teeth along the margins and are pointed at the tip. The leaves diminish in size as they rise along the stems. The upper leaf surface is dull green and sparsely covered with short stiff hairs while the lower surface is noticeably hairy – especially along the major veins. Up to 5 stiff stems arise from the basal leaf cluster and reach a mature height of about 4 feet.
Flowering occurs in late summer to mid-fall in dense clusters at the tips of the stems and side branches. Together they form a pattern that looks to be a compound panicle. Each bloom is about ½ inch in diameter and is composed of about a dozen white ray flowers that surround a white-colored central disk. These turn pinkish as the blooms age.
Walter’s aster (Symphyotrichum walteri)
Walter’s aster is one of the first asters that I began growing when I began to take this genus seriously about 10 years ago. This species is widely scattered throughout north peninsular Florida and in a few counties of the Panhandle, always in sunny and well-drained sites. In the early spring, it emerges to form rosettes of narrow linear leaves, no more than 1 inch long, but these are replaced by short, diamond-shaped leaves that clasp the stems and curl backward just a bit to appear almost like teeth. Mature plants produce an almost ball-like shape with many stiff stems that rarely stand more than 2 feet tall.
Flowering occurs in late fall into early winter, and numerous small flowers are produced across the tops of its many stems. Each is no more than ½ inch in diameter and composed of 1-2 dozen narrow light lavender to almost white ray flowers surrounding a yellow central disk. Walter’s aster has been an easy species to maintain in my landscape, but the seed is not reliably fertile here, perhaps owing to the paucity of pollinators at the time of year that my plants bloom. I always have to fight my desire to lie about the origin of its Latin name. Walter’s aster is named in homage to British botanist, Thomas Walter, famed author of Flora Caroliniana, the first North American flora to utilize the Linnean binomial taxonomic system a nd not for my renowned botanist friend, Walter Taylor.
A Note on Regionally Appropriate Native Plants
Florida has about 3,200 native species of vascular plants, and this diversity reflects the diverse habitats of the state. Some native plants occur throughout Florida, but most are not so widespread. Instead, their ranges are limited by climate, soils, hydrology, or history.
When deciding what Florida native plants to include in your landscape, consider whether the plant occurs naturally in your region and whether you have the appropriate habitat for a particular plant. For example, a plant from South Florida may not tolerate North Florida winters, or a North Florida plant may require a longer dormant season than is found in the southern regions of the state. To find information on the ranges of Florida native plant species, visit the Atlas of Florida Plants.
Another consideration when moving plants out of their native ranges is whether they may hybridize with local species in the same genus (or species if they differ at the variety level). Geographically isolated taxa are not always reproductively isolated. Such hybridization could impact the fitness of local populations. The ecological and economic damage done by invasive species is well known, and we should be cautious in moving Florida native species out of their natural ranges.
References
Atlas of Florida Plants. 2024. https://florida.plantatlas.usf.edu
Wunderlin, Ricard P., Bruce F. Hansen, and Alan Franck R. Flora of Florida. Volume VII: Dicotyledons, Orobanchaceae through Asteraceae. Gainesville: University Press of Florida, 2020.
About the Author
Craig Huegel has a PhD in Animal Ecology from Iowa State University. He is collections curator at the University of South Florida Botanical Gardens, and is the author of several books on native plants and landscaping for wildlife. His latest book is The Nature of Plants: An Introduction to How Plants Work, published by the University Press of Florida.
