Habitat
Aster undulatus is an inhabitant of dry, open, sandy and rocky woodlands and open clearings throughout eastern and central North America (Gleason and Cronquist 1991, Mohlenbrock 1975, Peterson and McKenny 1968, Rickett 1963, Gleason 1952, Small 1933).
A collection of A. undulatus from Alabama lists habitat as dry woods and dry, open places (University of Minnesota Herbarium (MIN)).
In Delaware, A. undulatus is common, occurring in dry woods throughout the Piedmont and Coastal Plain physiographic regions (McAvoy 1993).
Florida habitats include waste places with poor soil (Anglin 1993) and high pine-oak woods (University of Minnesota Herbarium (MIN)).
A collection from Georgia listed habitat as being dry woods near the Chattahoochee River (University of Minnesota Herbarium (MIN)).
Occupied habitat in Illinois consists of dry, open woods with thin soils over sandstone, open sandstone slopes and outcrops (Illinois Natural Heritage Division 1992, Mohlenbrock 1975).
In Indiana, A. undulatus habitat consists of dry, rocky woodlands and barrens, as well as high, open ridges and high, wooded banks (Homoya 1992, Deam 1940, University of Minnesota Herbarium (MIN)). Populations typically occur in association with calcareous substrates, but acidic sites are also known (Homoya 1992).
Kentucky populations of A. undulatus are known from wooded banks, dry-mesic woodlands and woodland edges throughout much of the state. A 1942 collection from McCreary County listed the species as being common in open hardwoods and burned over areas (University of Minnesota Herbarium (MIN)).
In Maine, a collection of A. undulatus was made from a dry roadside (University of Minnesota Herbarium (MIN)).
In Maryland, habitat includes the border of woods, clearings in rich woods, dry woods and sandy woodland borders (University of Minnesota Herbarium (MIN)).
Populations in New Hampshire are known from sandy, open woods and dry shaded slopes (University of Minnesota Herbarium (MIN)).
New Jersey collection labels list habitat as dry soil and woods. One collection noted the encroachment of the species along railroad tracks (University of Minnesota Herbarium (MIN)).
Collections of plants from New York suggest edges of thickets, sandy barrens, dry sandy fields, dry hilly woods and hills as occupied habitats (University of Minnesota Herbarium (MIN)).
In North Carolina, A. undulatus is fairly ubiquitous in dry to mesic forests, open woodlands and disturbed sites (roadsides along woods, etc.) (Weakley 1993, University of Minnesota Herbarium (MIN)). Sometimes it occurs in fire-maintained habitats, such as longleaf pine/turkey oak sandhills (Weakley 1993).
In Nova Scotia, A. undulatus habitat includes dry, open woods and thickets and is often found invading old fields (Maher et al. 1978, Roland and Smith 1969).
Aster undulatus is one of the most common asters in eastern Ohio, with numerous extensive populations (Cusick 1993). Within the state it occupies dry, open woods (mixed oak, oak-pine or other woodland communities) and thickets. These sites are well-drained and often acidic (Cusick 1993, Fisher 1988).
One doubtful record of the species is known from Ontario. Its habitat was described as dry, sandy woodlands (Semple et al. 1988, Argus et al. 1982-1987).
In Pennsylvania, A. undulatus is a common species, found in dry, well-drained, open woodlands, woods borders, scrub oak barrens and similar habitats (Kunsman 1993, Wiegman 1993, University of Minnesota Herbarium (MIN)). Associated plant species include Acer rubrum, Carya spp., Gaylussacia baccata, Hamamelis spp., Kalmia latifolia, Melampyrum lineare, Nyssa sylvatica, Pinus rigida, P. virginiana, Quercus ilicifolia, Solidago juncea, S. nemoralis and Vaccinium spp. (Kunsman 1993).
South Carolina habitat has been described as oak-hickory forest (University of Minnesota Herbarium (MIN)).
The habitat in the Great Smoky Mountains National Park in Tennessee is submesic to subxeric woods at low to mid elevations (Rock 1992). Collections of the species at the University of Minnesota Herbarium (MIN) list habitat within the state as dry, rocky woods and roadsides in forested and agricultural areas.
In Vermont, the habitat for this species is dry fields and large openings in dry woods (Popp 1993).
West Virginia habitats include open woods (University of Minnesota Herbarium (MIN)).