plant

Plants of the Eloise Butler Wildflower Garden
The oldest public wildflower garden in the United States

Common
Name

Scientific
Name

Plant
Family

Garden
Location

Prime
Season

White Wood Aster

Eurybia divaricata (L.) G. L. Nesom [formerly Aster divaricatus L.]

Aster (Asteraceae)
Woodland
Late Summer to Autumn
Other names and notes

Stems: White Wood Aster is an erect perennial that grows from 1 to 2-1/2 feet tall. Stems tend to have a slight zigzag to them and they can be spreading or sprawling. The stem within the inflorescence has dense very fine hair. Leaves are large and thin, ovate-lanceolate in shape with heart shaped bases, sharp coarse teeth on the margins, a pointed tip that usually has a twist to it. If there is any leaf hair it will be sparse. The underside may have have, particularly along the veins. Lower leaves are on long stalks. Upper leaves will be much smaller with short stalks, sometimes stalkless. The more basal leaves will drop by flowering time. The inflorescence is a loose grouping of somewhat flat-topped branched clusters (corymbs) branching from the top part of the stem. Several long green bracts may appear among the flowers. The flowers are about one inch wide composed of two types: 5 to 10+ white ray flowers that are pistillate and fertile, surrounding a central disc of 12 to 19+ bisexual, fertile, yellow disc florets that turn reddish at maturity. The lobes of the corolla are erect to spreading during flowering. The stamens, surrounding the style, protrude from the corolla. The petals can also have a lilac tinge of color. They also seem to pointing in various directions. The phyllaries of the flower head number 25 to 30 in 4 to 5 series, unequal in size, are rounded to pointed in shape and are whitish with dark green tips. The inner series can have a purplish tinge. Flower stalks are hairy. Seeds are a brown dry achene with 7 to 10 ribs and with a few fine reddish to cream colored bristles and hair for wind dispersion.

Habitat: White Wood Aster grows from a creeping branched rhizome, which will form colonies. It prefers the drier, well drained soil of open woods in partial to full shade. Best to plant in an area where it can sprawl out as the flower clusters held above the leaves are quite showy. Names: The genus Eurybia is from two Greek words - eurys meaning 'wide' and baiso, meaning 'few', alluding to the few wide-spreading ray florets. The species name, divaricata, refers to the 'spreading' or 'growing in a straggling' habit. The species was formerly named Aster divaricatus, however, all the new world asters, formerly in the genus Aster, have now been reclassified, most into the genus Symphyotrichum, several, like this species, to Eurybia. The plant author name ‘G. L. Nesom’ is for Guy L. Nesom (b. 1945) American botanist who has published papers on the nomenclature of asters.

Comparisons: The most likely species to confuse with this one is it's sister in the Eurybia genus, the Bigleaf Aster, E. macrophylla. Differences are that E. divaricata has white petals with little or no lilac color, fewer rays per flower head, and the leaves are only on the flowering stem, whereas E. macrophylla has more lilac color, 9 to 20 rays, and has basal leaves plus stem leaves. The Heart-leaved Aster, Symphyotrichum cordifolium, also have similar leaves, but the flower panicle is rounded, not flattened.

White Wood Aster
Flower detail
The flowers of White Wood Aster (above and below) are composed of 5 to 10+ white ray petals surrounding a central disc of numerous yellow disc flowers that turn reddish at maturity. The petals can also have a lilac tinge of color. They also seem to pointing in various directions. The phyllaries of the flower head (below left) have rounded to pointed in shape and are whitish with dark green tips. Note also the larger green bract on the stalk.
Phyllaries White Wood Aster flower bracts
Below: The seed head (left) with individual seeds (right); both from the disc florets.
Seed head seeds
Lower leaves (below center photo) are large and thin, ovate-lanceolate in shape with heart shaped bases, coarse teeth on the margins, a pointed tip that usually has a twist to it. The stem (lower right photo) has a slight zigzag pattern.
plant lower leaf Stem
 
White Wood Aster  
Notes: This aster, formerly classified as Aster divaricatus L., is not native to the State. It is native to the eastern United States and in Canada to Quebec and Ontario where it is considered rare and endangered. It was originally brought into the Garden by Eloise Butler in 1911 from Gillett's Nursery in Southwick, MA. She reported planting it on May 17th, 1911 along with a group of other species obtained from Gillett's Nursery. In her report to the Board of Park Commissioners in 1915, Eloise discussed the asters of the Garden. Her only comment on this species was that it had entirely died out. Martha Crone first planted it on Sept. 18, 1937, however, it escaped being on Martha Crone's 1951 Garden Census, but is present again today. Eurybia macrophylla is the only species of Eurybia native to Minnesota.  
 

 
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applies. Distribution principally from Wi, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.  
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