Stems: White Heath Aster is a native perennial aster with stems that can reach up to 3 feet high. The bottom 1/3 of the stem is usually unbranched but above that the plant can branch frequently creating a bush like appearance. Stems are hairy, green initially and becoming brown toward flowering time.
The leaves are narrow and small, with basal leaves no more than 1/2 inch across and up to 3 inches long, but most stem leaves are much narrower and shorter, all with rough edges from stiff hairs. The more upper stem leaves also have undersides with short stiff hair and a soft spine. Like the flowers, they are numerous and while alternate, are closely crowded. There are frequently fascicles of very small leaves in the leaf axils. Like most asters, the lower basal leaves drop away by flowering time.
The floral array is a branched panicle with flowers clustered tightly, frequently overlapping, along the panicle branches. The branch stems and the flower stalks are hairy.
Flowers: There are many small (1/3 to 1/2 inch) flowers composed of two types of florets: There are 10 to 18 white ray florets, although they may occasionally be light blue or pink. These are pistillate and fertile. The rays surround a group of 6 to 12+ fertile tubular disc florets. These have a yellow corolla with the five lobe tips at the throat slightly turned outward. Anthers of the five stamens of the disc florets are appressed against the style which has appendages at its tip. The style is exserted from the corolla throat when the floret opens. The disc floret corollas turn brownish at maturity. The green flower bracts on the flower stalks graduate into an overlapping series (3 to 4) of phyllaries surrounding the flower head; they are unequal in size, hairy, and with green spade-like or diamond shaped tips.
Seeds are a dry narrow cypsela, 1.2–2 × 0.4–0.6 mm in size, with tufts of white hair for wind distribution. The surface of the cypsela is faintly nerved. These very small seeds require light and warm soil to break dormancy, but do not need cold stratification. Seeds should be surface sown.
Habitat: Heath Aster grows from a rhizome with fibrous roots. This is a plant for full sun without excessive moisture - mesic to dry. It can withstand dry conditions. Besides seed dispersal, the plant will form colonies by creeping roots. Of all the white flowered asters, this is one of the easiest to identify due to the dense clusters of small flowers, the small heath-like leaves with rough edges and the hairy stem, brown at flowering time. The nursery trade frequently offers 'Aster ericoides' but many are not the native variety but are derived from European garden plants as explained at the bottom of the page.
Names: The species name, ericoides, refers to being "heath" like. All the new world asters, formerly in the genus Aster, have now been reclassified, most into the genus Symphyotrichum. The genus name is from the Greek symphysis, for 'junction', and 'trichos', for hair and, while obscure, it was first applied by Christian Gottfried Daniel Nees von Esenbeck in the 1800s in describing the type aster for the genus. A previously used scientific name for this plant that is no longer accepted is Aster multiflorus, which gave the plant its alternate common name of Many-flowered Aster. It was originally classified in 1753 as Aster ericoides by 'L.' which refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. His work was updated in 1995 by - ‘G. L. Nesom’ which is Guy L. Nesom (b. 1945) American botanist who has published papers on the nomenclature of asters.
Comparisons: This is the only white flowered aster in our area that has dense clusters of many small flowers combined with the dense small hairy leaves.
Above: Identifying characteristics. White Heath Aster has flowers with 10 to 18 white ray florets, although they may rarely be light blue or pink. The rays surround a group of 6-12+ yellow disc florets that turn brownish at maturity. These are 1/3 to 1/2 inch wide on densely packed on a branched panicle. Leaves are narrow, short, "heath" like, with rough edges on a hairy brownish stem at flowering time.
Below: 1st photo - The small green bracts on the stalks graduate into an overlapping series (3 to 4) of phyllaries, unequal in size, hairy, and with green spade-like or diamond shaped tips. 2nd photo - The underside of the upper leaves have dense short hairs. All leaves have stiff edge hair giving a rough texture.
Below: The difference in size between a basal left (bottom) and an upper stem leaf (top).
Below: The small seed head has white fluffy pappus attached to each small cypsela for wind dispersion.
Below: White Heath Aster grows fibrous rooted rhizomes.
Notes: White Heath Aster is not indigenous to the Garden but it is to the immediate area. Eloise Butler's records show that she first planted the species on October 4, 1908 with plants obtained at Indian Mounds (in St. Paul); again on April 29, 1912 with plants obtained from Gillett's Nursery, Southwick, MA; on Sept. 24, 1914 from Glenwood Park (which surrounded the Garden); in 1918, '19 and '24 from other places. The old botanical name she used in 1908 was Aster multiflorus. Martha Crone planted it in 1938 and 1945 and it was listed on her 1951 inventory of plants in the Garden at that time. Cary George reported planting it in 1995.
Varieties: There are two recognized varieties of this aster and both are found within Minnesota - var. ericoides and var. pansum. The latter, with a cormoid root system, is known only from specimens collected in Wilkin County. The former which has a spreading rhizomatous root system, is the norm. It is native to most counties in Minnesota, the exceptions being in the wetter north central area. In North America it is found in the eastern 2/3rds of the area with some exception along the gulf and east coasts. Asters are difficult to study. There are twenty-four species just of Symphyotrichum listed by the DNR and the U of M as being found in Minnesota, some with several subspecies.
Eloise Butler wrote about the asters in the Garden in her 1915 report to the Board of Park Commissioners. Of this species she said: "Aster multiflorus has been largely planted in the garden, but last season I found a specimen of it well established in my swampy meadow, where I never should have thought of planting it - the inhabitant of dry prairies. This aster with its small rigid leaves and multiplicity of flowers might well be called ericoides if the name had not been preempted, for it looks like a heath. Robust specimens are fully as fine as the overworked Spirea Van Houttei."
[Note: Eloise's comment about the name being preempted is a result of a name misapplication. Her problem with this plant is probably explained by this note from Flora of North America: "A number of aster cultivars are sold under the name "Aster ericoides." These are all derived from European garden plants and are either cultivars of S. dumosum, S. lateriflorum, S. pilosum, or S. racemosum, or hybrids involving one of those species and another taxon. The misapplication of the epithet ericoides dates back to the nineteenth century and has persisted in the horticultural literature."
Much the same text as Eloise's 1915 report was incorporated into an essay that was sent to The Gray Memorial Botanical Chapter, (Division D) of the Agassiz Association for publication in the chapter's member circular. Text here.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"