Symphyotrichum praealtum (Willowleaf Aster) growing along the boundary fence in the front pasture on 10-3-18, #514-33.

Willowleaf Aster, Willow Aster, Rodney’s Aster, Wild Aster

Symphyotrichum praealtum

sim-fy-oh-TRY-kum  pray-AL-tum

Synonyms of Symphyotrichum praealtum (34) (Updated of 12-4-23 from Plants of the World Online): Aster carneus Torr. & A.Gray ex Benth., Aster carneus var. subasper (Lindl.) Torr. & A.Gray, Aster coerulescens DC., Aster coerulescens var. angustior (Wiegand) Fernald, Aster coerulescens var. subasper (Lindl. ex Hook.) Fernald, Aster coerulescens var. typicus Cronquist, Aster eminens Willd., Aster lanceolatus Nutt., Aster nebraskensis Britton, Aster novi-belgii var. litoreus A.Gray, Aster obliquus Nees, Aster praealtus Poir., Aster praealtus var. angustior Wiegand, Aster praealtus var. coerulescens (DC.) A.G.Jones, Aster praealtus var. imbricatior Wiegand, Aster praealtus var. nebraskensis (Britton) Wiegand, Aster praealtus var. subasper Wiegand, Aster praealtus var. texicola Wiegand, Aster rigidulus Desf., Aster robustus Nees, Aster salicifolius Aiton, Aster salicifolius f. coerulescens (DC.) Voss, Aster salicifolius f. obliquus (Nees) Voss, Aster salicifolius var. stenophyllus E.S.Burgess, Aster salicifolius var. subasper (Lindl. ex Hook.) A.Gray, Aster salicifolius f. subasper (Lindl. ex Hook.) Voss, Aster subasper Lindl., Aster virgatus Nees, Symphyotrichum novi-belgii var. litoreum (A.Gray) G.L.Nesom, Symphyotrichum praealtum subsp. angustior (Wiegand) A.Haines, Symphyotrichum praealtum var. angustior (Wiegand) G.L.Nesom, Symphyotrichum praealtum var. nebraskense (Britton) G.L.Nesom, Symphyotrichum praealtum var. subasperum (Lindl.) G.L.Nesom, Symphyotrichum praealtum var. texicola (Wiegand) G.L.Nesom

Symphyotrichum praealtum (Poir.) G.L.Nesom is the accepted scientific name for the Willowleaf Aster. The species was named and described as such by Guy L. Nesom in Phytologia in 1995. It was first named and described as Aster praealtus by Jean Louis Marie Poiret in Encyclopedie Methodique in 1811.

The genus, Symphyotrichum Nees, was named and described as such by Christian Gottfried Daniel Nees von Esenbeck in Genera et Species Asterearum in 1832.

As of 12-4-23 when this page was last updated, Plants the World Online by Kew lists 100 species in the Symphyotrichum genus. It is a member of the plant family Asteraceae with 1,702 genera. Those numbers could change as updates are made on POWO. The number of genera in this family fluctuates quite often.

The distribution map for Symphyotrichum praealtum is from Plants of the World Online. Areas in green are where the species is native and purple is where it has been introduced. The map for North America above Mexico from the USDA Plants Database is similar and also includes New Mexico and Colorado (with no county data given) but not Manitoba and Quebec in Canada. No map is perfect and some are from old data.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.

There are several species of Symphyotrichum growing on the farm that drove me crazy for a few years. However, the S. praealtum was fairly easy because of the color and number of its ray florets, its narrow leaves with a network of reticulated veins, and the size the plants can grow to. On the farm, this species only grows along the south side of the farm in the south hayfield and along the fence in the front pasture. 

There are more photos from 2018, 2020, 2021, and 2022 at the bottom of the page under the links for further reading.

Toward the gate along the road in 2018, there were Symphyotrichum praealtum plants that were at least 8′ tall…

Symphyotrichum praealtum is a perennial U.S. native that grows from 2-5’ tall or more. They have a fibrous and rhizomatous root system and can form large colonies. Information online says they prefer a habitat in full sun with fertile, moist, loamy soil. Here on the farm, plants in the south hayfield grow in fairly sandy soil. While they are drought tolerant to a point, they grow their best during periods where they receive ample moisture. Information online says their preferred habitat is wet prairies, along streambanks and pond margins, bottomlands, etc. Here, they like the fence row and growing at the edge of the blackberry briars rather than the open pasture.  

The stems are unbranched except toward the top. They are usually hairless lower on the stems but have a fairly moderate amount in longitudinal lines toward the tips. The stems grow upright but have a tendency to flop as the plants grow taller from the weight of the flowers.

The leaves grow in an alternate pattern along the stems and can grow up to 5 1/2” long and 3/4” wide. They are lance-shaped (lanceolate),  narrowly ovate, to linear in shape, tapered at the base, and ending with a pointed tip. They have either short petioles (leaf stems) or may be sessile (no petioles. The leaf margins are smooth, having no teeth. The upper surface of the leaves are medium to light green, while the undersurface is lighter in color and where you can clearly see the reticulated network of veins. The lower leaves dry and fall off by the time appear in August.

The stems terminate in panicles of daisy-like flower heads and numerous leafy bracts. 

The flower heads are normally around 1/2-1” in diameter and are surrounded by a cup-shaped involucre with a series of overlapping bracts. The heads comprise of 20-35 ray florets in 1-2 series that are usually lavender in color, and 20-35 disc florets, yellow, turning reddish-brown after pollination. 

Plants bloom from August to October.

The flowers are visited by long and short-tongued bees, flies, butterflies, and skippers. 

I will continue to take more and better photos as time goes by. I always need better photos and I also add my observations to iNaturalist. It’s addictive…

I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF MISSOURI (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
DAVE’S GARDEN
MISSOURI PLANTS
MISSOURI BOTANICAL GARDEN
iNATURALIST
WILDFLOWER SEARCH
ILLINOIS WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
GO BOTANY
LADY BIRD JOHNSON WILDFLOWER CENTER

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂

Photos from 2018, 2020, 2021, and 2022…