Smooth Blue Aster

Perennials (15–)20–70(–120) cm, cespitose; stoutly short-rhizom­atous, with thick, woody caudices or a few, long rhizomes. Stems 1–5+, erect (straight, glaucous, sometimes reddish proximally), glabrous, sometimes sparsely hirsute distally. Leaves (glaucous) thick, firm, ± fleshy, margins crenate-serrate or -serrulate or entire, scabridulous, apices mucronulate, faces glabrous; basal usually withering by flowering or sometimes persistent (var. purpuratum), petiolate (petioles ± winged, bases dilated, sheathing), blades spatulate or oblong to ovate or lanceolate-ovate, 30–200 × 10–25(–30) mm, bases attenuate or cuneate to rounded, margins crenate-serrate to serrulate, apices acute to obtuse or rounded; proximal cauline often withering by flowering, petiolate or subsessile or sessile (petioles narrowly to broadly winged, clasping), blades ovate or oblong-ovate to lanceolate or linear-lanceolate, sometimes ± panduriform, (40–)80–150(–180) × (10–)20–45 mm, bases attenuate to rounded or ± shallowly auriculate-clasping, margins entire or shallowly crenate-serrate, minutely scabrous, apices acute or obtuse, callus-pointed; distal sessile, blades lance-ovate or lanceolate to linear, 7–45 × 1–14 mm, progressively reduced distally (abruptly so in arrays), bases auriculate and ± clasping to rounded, margins entire. Heads in broad, sometimes ± flat-topped, paniculiform arrays, branches stiffly ascending (rarely arching), leafy with small, gradually reduced branch leaves. Peduncles 0.2–6+ cm, glaucous, glabrous or puberulent in lines, bracts 3–6, densely spaced, subulate or linear-lanceolate to linear, subclasping, apices sometimes purplish, grading into phyllaries. Involucres campanulate to cylindro-campanulate, (4.2–)5–7(–8) mm. Phyllaries in 4–6 series, appressed, subulate or lanceolate (outer) to oblong-lanceolate or linear-lancolate or -oblanceolate, unequal (sometimes appearing subequal), bases indurate ¹ / 2 – ³ / 4 , margins scarious, erose, hyaline, ciliolate distally, green zones mostly diamond-shaped to ± lanceolate (some inner, or most in var. geyeri), apices acute to acuminate, sometimes ± obtuse, red-mucronate or apiculate, faces glabrous. Ray florets (11–)13–23(–34); corollas usually pale to dark blue or purple, seldom white, laminae (6–)7.2–11.3(–14.6) × 1.5–2.5 mm. Disc florets (17–)19–33(–43); corollas yellow turning purplish red, 3.5–6.1 mm, tubes slightly shorter than funnelform throats, lobes triangular, (0.4–)0.6–1 mm. Cypselae deep purple to brown, oblong-obovoid, compressed, 2–3.5 mm, 4–5-nerved, faces glabrous or glabrate; pappi tawny to red- or rose-tinged, 5–7 mm.

Aster laevis Linnaeus, Sp. Pl. 2: 876. 1753

smooth blue aster
purple aster
smooth blue American-aster
smooth aster

Information on state-level protected status of plants in the United States is available at Plants Database.

More info for the terms: achene, caudex, forb, fruit, rhizome

Smooth blue aster is a moderately tall (12 to 40 inches [30 -100 cm]) native perennial forb, with a stout rhizome and branching caudex.  There are one to several erect stems.  The fruit is a one-seeded achene [14,19,36].

Smooth blue aster is widely distributed in the United States and Canada from the Atlantic Coast to the eastern slopes of the Cascade Range, south to New Mexico, Texas, and Georgia [19,40,43].  In eastern North America, S. l. var. laeve is the most common.  This variety intergrades in the Great Plains with S. l. var. geyeri.  S. l. var. geyeri's distribution continues through the mountain states to Yukon Territory and British Columbia, eastern Washington and Oregon, south through Utah to New Mexico and Texas [19]. It is cultivated in Hawaii [54].  S. l. var. coccinnus occurs in Georgia, North Carolina, Tennessee, and Virginia [50].

More info for the terms: cover, fire regime, forbs, rhizome

Smooth blue aster sprouts from the rhizome after being top-killed by fire. It occurs in a number of plant associations that have frequent fire regimes.  Presumably, it is adapted to fire, though no specific information is available in the literature. In general, forbs are more adversely affected by fires that occur later in the spring.  Usually cover is reduced, while overall composition remains little affected.  Forbs are much less affected by dormant-season fires than by spring fires [8]. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".

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More info for the terms: geophyte, hemicryptophyte

   Hemicryptophyte    Geophyte

More info for the terms: cover, frequency, mesic, xeric

Smooth blue aster occurs on a wide variety of sites, including moist, sandy soil in woods, dry woods, and open areas, and mesic and dry-mesic prairies [30,40].  Cover and frequency of smooth blue aster is highest on sites with high light intensities, though it occurs on more shaded sites as well [41].  It usually sustains higher populations on wetter, more poorly drained glacial till soils in eastern Illinois and western Indiana [6].  In Michigan, however, Beaufait [4] reported that although smooth blue aster occurs on mesic and transitional sites, it is more likely to be encountered on the more xeric sites. Elevation occurrence data from selected western states is as follows [12]:                feet             meters Utah        5,700 - 8,600    1,737 - 2,621 Colorado    5,000 - 9,300    1,524 - 2,835 Wyoming     3,700 - 7,600    1,128 - 2,316 Montana     2,300 - 6,000      701 - 1,829

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

     1  Jack pine
    14  Northern pin oak
    15  Red pine
    16  Aspen
    18  Paper birch
    19  Gray birch - red maple
    20  White pine - northern red oak - red maple
    21  Eastern white pine
    25  Sugar maple - beech - yellow birch
    26  Sugar maple - basswood
    27  Sugar maple
    42  Bur oak
    44  Chestnut oak
    46  Eastern redcedar
    52  White oak - black oak - northern red oak
    53  White oak
    70  Longleaf pine
    75  Shortleaf pine
    78  Virginia pine - oak
    79  Virginia pine
    83  Longleaf pine - slash pine
    84  Slash pine
   237  Interior ponderosa pine

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

   FRES10  White - red - jack pine
   FRES12  Longleaf - slash pine
   FRES13  Loblolly - shortleaf pine
   FRES14  Oak - pine
   FRES15  Oak - hickory
   FRES18  Maple - beech - birch
   FRES19  Aspen - birch
   FRES21  Ponderosa pine
   FRES36  Mountain grasslands
   FRES38  Plains grasslands
   FRES39  Prairie

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

   K011  Western ponderosa forest
   K016  Eastern ponderosa forest
   K017  Black Hills pine forest
   K050  Fescue - wheatgrass
   K051  Wheatgrass - bluegrass
   K056  Wheatgrass - needlegrass shrubsteppe
   K063  Foothills prairie
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss
   K066  Wheatgrass - needlegrass
   K067  Wheatgrass - bluestem - needlegrass
   K068  Wheatgrass - grama - buffalograss
   K069  Bluestem - grama prairie
   K070  Sandsage - bluestem prairie
   K074  Bluestem prairie
   K075  Nebraska Sandhills prairie
   K081  Oak savanna
   K082  Mosaic of K074 and K100
   K084  Cross Timbers
   K095  Great Lakes pine forest
   K099  Maple - basswood forest
   K100  Oak - hickory forest
   K102  Beech - maple forest
   K103  Mixed mesophytic forest
   K104  Appalachian oak forest
   K106  Northern hardwoods
   K107  Northern hardwoods - fir forest
   K108  Northern hardwoods - spruce forest
   K109  Transition between K104 and K106
   K110  Northeastern oak - pine forest
   K111  Oak - hickory - pine forest
   K112  Southern mixed forest

Fire top-kills smooth blue aster.

More info for the term: forbs

White-tailed deer will graze smooth blue aster, selecting it over other available forbs [14].

More info for the term: association

Smooth blue aster is a component of many types of plant associations,
most notably of mixed prairie types such as needlegrass (Stipa comata, S.
spartea)-blue grama (Bouteloua gracilis) and wheatgrass (Elymus
lanceolatus, Pascopyrum smithii)-junegrass (Koeleria cristata) types
[10].

Smooth blue aster is an understory dominant or a component in a number of
quaking aspen (Populus tremuloides) community types, including a quaking
aspen-Missouri gooseberry (Ribes missouriense)-roughleaf ricegrass
(Oryzopsis asperifolia)-smooth blue aster community type [39].  It also
occurs as an understory dominant in a quaking aspen-Bigelow ligularia
(Ligularia bigelovii) community type [34].  Smooth blue aster is a leading
dominant in a smooth blue aster-western yarrow (Achillea millefolium v.
lanulosa) plant association found in openings in quaking aspen parklands
[29].

More info for the term: forb

Forb

More info for the term: seed

In a study of prairie regeneration in which herbicides were applied to
control quackgrass (Agropyron repens), smooth blue aster failed to establish
in plantings treated with either glyphosate or dichlobenil [49].
Picloram, tebuthiuron, and hexazinone all suppressed growth of smooth
aster, either alone or in combination.  Applied alone, 2,4,D-E did not
suppress smooth blue aster growth [31].

Grazing by deer does not appear to affect survival of established plants
or seedlings, as long as only the stem tips are removed.  Most plants
damaged by deer responded with vigorous growth the following season
[14].  Weaver and Hansen [47] classify smooth blue aster as a decreaser under
grazing.

Plants grown under nursery conditions had excellent rates of survival
when planted in the field.  Nursery stock was planted at a rate of 3.5
ounces of seed per 100 square feet (11 gm/sq m), and resulted in a
harvest of 9.5 pounds of seed per 100 square feet (0.5 kg/sq m) [46].

More info for the term: seed

Smooth blue aster has high nutritional value, decreasing with maturation.
Nutritional values for aerial portions are as follows [7]:

              digestible protein (%)  cellulose (%)  digestibility(%)

leaf stage       11.6                    27.2           77.1
heading           5.9                    28.8           55.2
seed ripening     5.2                    31.2           61.8

     AL  AZ  CO  CT  DE  GA  HI  ID  IL  IN
     IA  KS  KY  LA  ME  MD  MA  MI  MN  MO
     MT  NE  NV  NH  NJ  NM  NY  NC  ND  OH
     OK  OR  PA  RI  SC  SD  TN  TX  UT  VT
     VA  WA  WV  WI  WY  AB  BC  MB  NB  NF
     NS  ON  PE  PQ  SK  YT

Smooth blue aster is palatable to white-tailed deer and livestock [14,47].
It is likely that it is palatable to other species as well, but
documentation is not available.

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Smooth blue aster blooms from August to October [11].  The lowermost leaves are early deciduous; the remaining leaves are dropped after frost top-kills the plant [19].

More info for the terms: fruit, mesic, prescribed fire, presence, wildfire

Most reports on the effects of fire in communities occupied by smooth aster are inconclusive as to its response [1,17].  The number of leaves per individual plant increased following a late spring prescribed fire, with no change in the number of flowers or fruit per individual for either the early spring or late spring prescribed fires [27]. Prescribed spring fires had variable effects on flowering in smooth aster, depending on habitat.  Flowering was inhibited on dry-mesic prairie site on an undisturbed south-facing slope and on a highly disturbed, level, mesic prairie site.  Flowering was stimulated on sloping and level mesic undisturbed prairie sites [33].  Three years after a wildfire in jack pine (Pinus banksiana) stands, smooth blue aster was an important component of the regenerating plots.  These sites had standing dead trees, which indicates that there was probably a substantial loss of crown shading [2]. Smooth blue aster was listed as a decreaser under an annual early spring burning regime, and also after a spring wildfire [3,44].  Scheiner [37] reported the presence of smooth blue aster on sites that had recently undergone prescribed burns, as well as on older postfire seral sites.

More info for the terms: ground residual colonizer, herb, rhizome, secondary colonizer

   Rhizomatous herb, rhizome in soil    Ground residual colonizer (on-site, initial community)    Secondary colonizer - off-site seed

More info for the terms: scarification, seed, stratification

Smooth blue aster reproduces well from seed.  Seeds do not require either scarification or stratification [20,32].  Greenhouse germination trials showed that, without stratification, initial germination occurs at 7 days, and peak germination occurs at 20 days [32].  Seed banking is not apparent; soil samples collected in August (probably before seed release) contained no germinable smooth blue aster seeds [37].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

    2  Cascade Mountains
    4  Sierra Mountains
    5  Columbia Plateau
    6  Upper Basin and Range
    8  Northern Rocky Mountains
    9  Middle Rocky Mountains
   10  Wyoming Basin
   11  Southern Rocky Mountains
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains
   15  Black Hills Uplift
   16  Upper Missouri Basin and Broken Lands

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Thirty years after study plots had been retired from heavy grazing, smooth blue aster was found only on the edges of the sites nearest undisturbed native prairie [18].  Smooth blue aster is found on roadsides and other previously disturbed areas but is probably not an initial colonizer. Smooth blue aster is probably not tolerant of deep shade but will tolerate light or intermittent shade.

Species name―
Aster laevis L. [21,22,40,53]

Infrataxa―
Aster laevis var. concinnus (Willd.) House [21,22,40,53]
=Symphyotrichum laeve var. concinnus (Willd.) Nesom [55,56]
Aster laevis var. geyeri Gray [21,22,40,53]
  =Symphyotrichum laeve var. geyeri (Gray) Nesom [55,56]
Aster laevis var. guadalupensis A.G. Jones [21,22,40,53]
  =Symphyotrichum laeve var. geyeri (Gray) Nesom [55,56]
Aster laevis var. laevis [21,22,40,53]
=Symphyotrichum laeve var. laeve [55,56]
Aster laevis var. purpuratus (Nees) A.G. Jones [21,22,40,53] 
  =Symphyotrichum laeve var. purpuratus (Nees) Nesom [55,56]

The accepted scientific name for smooth blue aster is Symphyotrichum
laeve (L.) A.& D. Löve.  Recognized varieties are as follows [55,56]:

Symphyotrichum laeve var. concinnus (Willd.) Nesom
Symphyotrichum laeve var. geyeri (Gray) Nesom
Symphyotrichum laeve var. laeve
Symphyotrichum laeve var. purpuratus (Nees) Nesom  

More info for the term: restoration

Direct seeding of smooth blue aster was successful in establishing plants along highway margins for prairie restoration [32].  Smooth blue aster is recommended in seedings and plantings for rehabilitation or restoration of native mixed-grass and tallgrass prairies [31,32,49].

Symphyotrichum laeve (formerly Aster laevis) is a flowering plant native to Canada, the United States, and Coahuila (Mexico). It has the common names of smooth blue aster, smooth aster, smooth-leaved aster, glaucous Michaelmas-daisy and glaucous aster.