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A Comprehensive Guide to Boreal Aster (Symphyotrichum boreale)

Boreal Aster (Symphyotrichum boreale) is a herbaceous perennial that is native to the northern United States and Canada. This species is a host to the Pearl Crescent (Phyciodes tharos) and American Lady (Vanessa virginiensis) butterflies and several moths. Growing from 0.5 to 3 feet tall, this species grows in wetlands such as fens, marshes, bogs, stream margins, and swales. The white, pink, lavender to bluish ray flowers and yellow disk flowers that bloom from July to October and the plant is hardy in zones 4-5.

Taxonomy and Naming of Boreal Aster (Symphyotrichum boreale)

Herbarium specimen of boreal aster (Symphyotrichum boreale).
Herbarium Specimen — Symphyotrichum boreale (Torr. & A.Gray) Á.Löve & D.Löve collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)

Taxonomy

Boreal Aster (Symphyotrichum boreale) was originally named and described by John Torrey and Asa Gray, both American botanists in 1841 as Aster laxiflorus var. borealis. In 1982, it was placed in the Symphyotrichum genus, by Askell Love and Doris Love, an Icelandic botanist and Swedish botanist. It has kept this same name since and is a member of the Aster Family (Asteraceae).

Meaning of the Scientific and Common Names

Scientific Name

The genus name, Symphyotrichum, was re-established when the North American Aster species were renamed. It derives its name from the Greek words “Symphysis” and “thriks“, which together mean hair growing together (Wikipedia). The species name, boreale, is Latinized for the general “boreal” distribution of the species.

Common Name and Alternative Names

The common name comes from the distribution of the species. It is also called the northern marsh aster (Harms 2001), rush aster (Jones 2019), northern bog aster (Hlina and Anderson 2011), slender white, and bog aster (Flora of North America).

Physical Description

Close-up of flower of boreal aster (Symphyotrichum boreale).
Flower of boreal aster (Symphyotrichum boreale) — Joshua Mayer, CC BY-SA 2.0, via Wikimedia Commons
  • Plant Type: This plant is a herbaceous perennial.
  • Height: 0.5 feet to 3 feet tall
  • Stem: The stems are erect and glabrous.
  • Leaves: The leaves are alternate, basal and cauline, lanceolate to linear and have somewhat serrate to entire margins. They are 1 to 6 inches long and < 0.25 inches wide (Minnesota Wildflowers).
  • Flower color: white, pinkish, lavender to bluish ray flowers and yellow disk flowers aging to purple.
  • Blooming period: This plant blooms from July to October.
  • Fruiting type and period: This plant has achenes that mature in the late fall and winter.

Range of Boreal Aster in the United States and Canada

Range map of boreal aster (Symphyotrichum boreale) in the United States and Canada.

This aster species is native to the northern United States and Canada, except for Nunavut. It is considered to rare in a lot of its southern range and in the province of Yukon in Canada.

Habitat

Fen habitat showing vegetation.
Fen Habitat — Tim Redmond, CC BY-SA 4.0, via Wikimedia Commons

This species grows in wetlands that have a high pH such as fens (Djan, et al 2004), marshes, bogs, ponds and stream margins, and swales.

Hosted Insects

Pearl Crescent (Phycoides tharos) butterfly on branch.
Pearl Crescent (Phycoides tharos) on Vegetation — ALAN SCHMIERER, CC0, via Wikimedia Commons

Most species of Symphyotrichum are hosts for the Pearl Crescent (Phyciodes tharos) and the American Lady (Vanessa virginiensis) butterflies. It also hosts a buck moth (Hemileuca maia) and several other moths.

Other Supported Wildlife

Bumblebee on pink flower.
Bumblebee on Flower — Weerlicht, CC0, via Wikimedia Commons

This species is a nectar source to other butterflies, skippers, bees, and wasps during the growing season.

Frequently Asked Questions

Does this plant have any ethnobotanical uses?

The Native American Ethobotanical Database does not cite this species specifically, but asters in general have been used for medicines, jewelry, foods, and for ceremonial uses.

How is this plant distinguished from other Asters?

This species is has been noted as being similar to the anticosti aster (Symphyotrichum anticonstense) (Haines 2000). However, the anticosti aster has a thicker stem.

This species is in a complex with Nahanni Aster (Symphyotrichum nahanniense) and Welsh’s Aster (S. welshii). They can be told apart by the fact that the nahanni aster grows only in hotsprings in the Nahanni National Park Reserve and the Welsh’s aster has pappus with lengths that are less than or equal to the disc corolla. The boreal aster has pappus that are generally longer than the disc corolla (Owen, et al 2006).

Is this plant invasive?

This plant has not been noted as being weedy.

Gardening with Boreal Aster

White flowers of boreale aster on a river edge.
Boreale Aster (Symphyotrichum boreale) — Sara L Giles, CC0, via Wikimedia Commons

Hardiness

This species is hardy in zones 4-5. If your garden is within these zones and you have the right growing conditions (soil, moisture and exposure), you may well be able to grow this plant. However, if planted outside of its range, the hosted species may not recognize the plant or be harmed by ingesting a different species with an unfamiliar chemical composition.

Optimal Conditions

This species can grow in full sun to partial-shade in moist well-drained soil that has a high pH.

References

  • Djan-Chekar, Nathalie, Luc Brouillet, Claudia Hanel, Stuart Hay, and John E. Maunder. 2004. Vascular Plants of the Island of Newfoundland, Canada: Recent Additions and Rediscoveries. Rhodora 106: 167-177.
  • Haines, Arthur. 2000. Rediscovery of Symphyotrichum anticostense in the United States. Rhodora 102: 198-201.
  • Harms, Vernon L. 2001. Vascular Plants of the Peturrson Ravine Area Along the South Saskatchewan River, in Saskatoon, SK. Blue Jay 59: 134-152.
  • Hlina, Paul S. and Derek S. Anderson. 2011. Wetland Assessment and Inventory of the Pokegama Carnegie Wetland State Natural Area, Douglas County, Wisconsin. Michigan Botanist 50: 2-25.
  • Jones, Casey. 2019. A birder’s-eye view of Cedar Creek Corridor. Indiana Native Plant Society 26(1): 19-20.
  • Owen, Elliott, John C. Semple, and Bernard R. Baum. 2006. A multivariate morphometric analysis of the Symphyotrichum boreale-S. nahanniense-S. welshii complex (Asteraceae: Astereae). Canadian Journal of Botany 84: 1282-1297.
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Robert Coxe

Robert Coxe

Robert Coxe is a professional ecologist and botanist who has worked as the State Ecologist of Delaware and as an ecologist for the Western Pennsylvania Conservancy. He is also a former Past-President of the Pennsylvania Academy of Science. He currently is an innkeeper at McMullen House Bed & Breakfast LLC and a web designer and owner for Silphium Design LLC.

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