Symphyotrichum cordifolium (Blue Wood Aster)

Plant Info
Also known as: Heart-leaved Aster, Heart-leaved American Aster, Broad-leaved Aster, Lowrie's Blue Wood Aster
Family:Asteraceae (Aster)
Life cycle:perennial
Habitat:part shade, shade; average to moist soil; woods, thickets, floodplain forest, wooded bluffs, stream banks
Bloom season:August - October
Plant height:1 to 4 feet
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 7+petals Cluster type: panicle

[photo of flowers] Branching cluster of 20 to 300+, stalked, daisy-type flowers at the top of the plant and arising from upper leaf axils. Flowers are about ½ inch across with 7 to 15 petals (ray flowers) surrounding a creamy yellow center disk that turns reddish with age. Ray color ranges from nearly white to pale blue to lavender.

[photo of phyllaries] Surrounding the base of the flower are 4 to 6 layers of narrow, sharply pointed bracts (phyllaries), the outermost typically green, the inner greenish white at the base with long, diamond shaped green tips that are often red at the apex. Phyllaries are usually hairless, sometimes with a few minute hairs. Flower stalks are up to ¾ inch long with a few, small, leaf-like bracts and may have sparse hairs around the edge.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of lower stem leaf] Leaves are thin, coarsely toothed around the edges, and mostly strongly heart-shaped. Both surfaces are hairless to variously hairy, sometimes just hairy on the veins. Basal and lower stem leaves are up to 6 inches long and 3 inches wide, typically wither away by flowering time, and have long stalks with narrow wings. Farther up the stem, stalks become shorter and may be somewhat clasping, wings become slightly broader, and the blades less strongly heart-shaped to rounded at the base

[photo of uppermost leaves] Uppermost leaves and into the flower clusters are reduced to stalkless, lance-elliptic bracts that are toothless or nearly so. Stems are single or a few from the base, mostly erect to ascending but may flop over, usually hairless except for short hairs in the flower cluster, and becoming somewhat woody at the base with age.

Fruit: Fruit type: seed with plume

[photo of seed head] Flowers become seed heads with tufts of light brown to pinkish hair to carry them off in the wind.

[photo of seeds] Seed is light brown to purplish, up to 2.5 mm long, angled with 4 or 5 veins.


Asters can be difficult to ID. Blue Wood Aster is distinguished by a combination of traits: stem usually hairless below the flower cluster; thin, mostly strongly heart-shaped leaves with coarsely toothed edges and narrowly winged leaf stalks, upper leaves more rounded at the base and lance-elliptic with broader wings, the uppermost leaves into the flower clusters stalkless; ½-inch pale blue to lavender (or whitish) flowers with 7 to 15 rays, and a panicle with 20 to 300+ flowers.

Of the other blue/violet asters with heart-shaped leaves, Drummond's Aster (Symphyotrichum drummondii) is consistently more densely hairy, Lindley's Aster (S. ciliolatum) leaves are less strongly heart-shaped with broader wings on the stalks,  Short's Aster (S. shortii) has nearly toothless leaves that are proportionately narrower, Big-leaf Aster (Eurybia macrophylla) lower leaves are persistent through flowering, proportionately broader with clasping stalks. Arrowleaf Aster (S. urophyllum) has heart-shaped leaves with narrow wings on the lower stem, but has smaller white flowers arranged in tighter clusters.

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More photos

Photos by K. Chayka taken in Chisago, Hennepin and Nicollet counties. Photos by Peter M. Dziuk taken in his garden. Symphyotrichum cordifolium (plant) by Richard Spellenberg used under CC BY-NC-SA 3.0.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Ron Johannsen - Trenton Lake
on: 2020-09-11 16:31:21

Yes, so nice to see each Fall. Native hardwood maple-basswood forest. Many bottle gentian this year.

Posted by: Carole Peter - Maple Plain
on: 2021-05-24 10:36:53

In western Hennepin County, both this aster and, unfortunately, the dreaded creeping [creepy] bellflower occur. In early spring, before the long stalks shoot up, these look very much the same. Through this website, I was able to figure out that the rough-leaved plants are the bellflowerr, and the smoother-leaved plants are the aster.

Posted by: L. Ian - Minneapolis
on: 2022-07-18 02:42:51

I would also like to say that these plants look very similar to Creepy Bellflower (Campanula rapunculoides) before they start growing their flowers. I have been trying to eradicate the dreaded bellflower for a couple years, and I mistakenly ended up pulling a couple of these plants (luckily there are a lot more still present). Since these don't bloom until late summer, it can be easy to mistake the two plants I think.

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