Eurybia divaricata
Encyclopedia
Eurybia divaricata commonly known as the white wood aster, is an herbaceous plant native to eastern North America
. It occurs in the eastern United States
, primarily in the Appalachian mountains
, though it is also present in southeastern Canada
, but only in about 25 populations in the provinces of Ontario
and Quebec
. In the U.S. it is abundant and common, but in Canada it is considered threatened due to its restricted distribution. It can be found in dry open woods as well as along wood-edges and clearings. The species is distinguished by its flower heads that have yellow centers and white rays that are arranged in flat-topped corymbiform arrays, emerging in the late summer through fall. Other distinguishing characteristics include its serpentine stems and sharply serrated narrow heart-shaped leaves. It is very similar to and often confused with E. chlorolepis
, E. schreberi
and Symphyotrichum cordifolium
, though E. schreberi differs in having wider leaves with more teeth, while E. chlorolepis has more rays, longer involucre
s, and only occurs in the southern U.S. from Virginia
to Georgia
. The white wood aster is sometimes used in cultivation in both North America and Europe
due to it being quite tough and for its showy flowers.
s and forms dense colonies
of clones
that lack sterile rosettes. The rhizomes are branched, elongated and become woody with age. One simple erect stem is present per plant. It is flexible and nearly hairless to finely hairy near the base, though densely covered with fine hair towards the extremities.
Three types of leaves
with differing morphology
are present: cauline leaves, or those that appear on the stem from the middle of the plant upwards; basal leaves, or those that are present at the base of the plant; and distal leaves, which are those found on the extremities of the plant. All types are thin and sharply serrated with 6 to 15 pointed teeth per side. They are ciliate, meaning they have small hairy projections emerging from the margins of the leaf, while the apices, or tips of the leaves, are acuminate, meaning they taper to a point. The adaxial (i.e. upper) surfaces of the leaves are nearly hairless or sparsely hairy, while the abaxial (i.e. lower) surfaces are sparsely hairy with the veins being more villous, or covered in shaggy hairs.
The basal leaves are ovate, or egg-shaped, with bases that are cordate, or heart-shaped. The blades measure 1.9 to 6.5 cm in length by 1.7 to 6 cm in width and have petiole
s ranging in length from 2 to 7 cm. They wither when the plant flowers. The cauline leaves have petioles measuring 2.5 to 7 mm long that are often winged. Their blades are also ovate, though the bases may be cordate to rounded. They measure 2 to 20 cm long by 1 to 10 cm wide, making them often much longer than the basal leaves. The distal leaves are typically sessile
, meaning that no petiole is present, though they are sometimes subpetiolate, meaning a very short petiole is present. The blades are ovate to lanceolate, meaning lance-shaped, with rounded bases and are 0.5 to 2 cm long by 0.1 to 0.8 cm wide.
The capitula
, or flower heads, are arranged in relatively flat-topped corymbiform arrays. The capitula number anywhere from 4 to 50 and up to 100 or more in exceptional cases. The peduncle
s, i.e. the flower stalks, are up to 1.5 cm in length and are densely covered with non-gland
ular hairs. Bracts, modified leaves that appear at the axil of a peduncle, are typically absent, though in some cases up to two are present. The involucre
s, which are the whorls of small, scale-like modified leaves that appear at the base of the capitulum, are in between cylindric and campanulate (i.e. bell-shaped) in shape and measure 4.2 to 6 mm long, making them much shorter than the pappi
.
The phyllaries, which are the small leaves that make up the involucre, number from 25 to 30 and are arranged in 4 to 5 series. The inner phyllaries are between linear and lanceolate in shape with a purplish colouration towards the apices, while the outer ones are more oblong. All of the phyllaries are strongly unequal with hardened bases, margins that are somewhat scarious (i.e. thin, membranous and dry) as well as fimbriate-ciliate, meaning fringed with hair at the margins. Their apices are rounded to acute in shape, while the surfaces are sparsely haired, though sometimes sparsely covered in stipular
glands. Their chlorophyll
ous zones, a darker green zone where chlorophyll is concentrated, appear on the upper half of the outer phyllaries, to the upper third or along the outer midveins of the inner phyllaries. The outer phyllaries typically measure 0.7 to 1.5 mm wide with the lengths rarely exceeding 2.5 times the width.
As with most members of the composite family
, the actual flower
s appear in two different froms: as ray florets, which have strap-like appendages that look like petal
s and project around the outside of the capitulum, and as disc florets, which appear at the center of the flower head and are very small. The ray florets number between 5 and 10, though as many as 12 may be present. Their straps are white and measure 6 to 12 mm long by 1.5 to 2.2 mm wide. The disc florets number from 12 to 19 and up to 25 and have yellow corollas (i.e. petals, though they are fused into a tube) that are 4.1 to 4.8 and exceptionally 5.5 mm long. Their corollas are abruptly ampliate, or enlarged, with tubes that are longer than their campanulate throats. The tubes measure 2.3 to 2.6 mm while the throats are typically only 0.9 to 1.2 mm long. The lobes, i.e. the friges of the throat, are reflexed and lanceolate in shape, measuring 0.7 to 1.4 mm.
The fruit are cypselae, a type of achene
, which are brown in colour, slightly compressed and are between cylindric and obovoid, or inversely egg-shaped. They are between 2.6 and 3.8 mm in length and sparsely strigillose, or set with stiff bristly hairs, with 7 to 10 ribs, which themselves are tan to stramineous (i.e. straw-coloured). The pappi
, which are modified sepals, are made up of reddish to cream-coloured bristles that are 3.7 to 5 mm long, making them equal to or longer than the disc corollas in length. The bristles are fine and barbellulate, or barb-like, though they may be sometimes more or less clavate, or club-shaped, towards their apices.
), which was previously considered conspecfic with E. divaricata. E. chlorolepis differs in having flower stalks that are longer than 1.5 cm, while those of E. divaricata are shorter than this. The involucre
s of the mountain wood aster are generally between 6.5 and 9 mm in length, while those of the white wood aster are normally from 4.2 to 6.5 mm long, but in rare cases they may be as long as 7.5 mm. The mountain wood aster almost always has more rays than the white wood aster: the former usually has 12 to 16, but occasionally as few as 10, while the latter generally has 5 to 10 and never more than 12. The rays are also longer on the mountain wood aster at 17 to 18 mm in most cases, while the white wood aster's are generally only 10 to 15 mm. Lastly, E. chlorolepsis is only present from southern Virginia
south to Georgia
in the Appalachian Mountains
at altitudes of 1200 to 2000 metres, while E. divaricata can be found from southern Canada south to Alabama
, meaning their ranges only overlap in the southern United States, and there only at high elevations.
Another species commonly confused with the white wood aster is Schreber's aster (Eurybia schreberi
). Schreber's aster is typically found on moister soils, though it can also be found on mesic
sites. While much of their ranges overlap, Schreber's aster is not found south of Virginia or Tennessee
. Schreber's aster can also be distinguished by the more numerous teeth on the leaves, typically numbering 15 to 30 per side to the white wood aster's 6 to 15 per side. The leaves are wider on Schreber's aster with broader sinuses at the bases. The flower stalks are also densely hairy on the white wood aster, while they are only sparsely haired on Schreber's aster. Lastly, the clones
of E. schreberi have sterile rosettes, while those of E. divaricata do not.
Two more superficially similar plants include the bigleaf aster (Eurybia macrophylla
) and the heartleaf aster (Symphyotrichum cordifolium
), though both usually have blue or pale blue rays, while those of E. divaricata are always white. Both species sometimes have white rays in rare cases, but E. macrophylla can still be distinguished by its larger and broader leaves and S. cordifolium by its straighter and branched stems.
sites in eastern deciduous and mixed deciduous woods as well as on edges, clearings, and roadsides. It is most common at altitudes ranging from 0 to 1200 metres, though it can be found as high as 1700 metres. In Canada it is present in Ontario
and Quebec
, while in the United States it can be found in all states east of and including Michigan
, Ohio
, Kentucky
, Tennessee
and Alabama
, but excluding Florida
. It also has been introduced to Europe
, particularly to the Netherlands.
The species is known from only 25 locations in Canada, and is considered threatened.
, it does have its niche, especially in North American native gardens. The plant flowers earlier than many other asters, does not require any staking to support it and flowers well in shade. It is attractive to gardeners due to its showy white flowers that emerge in mid to late summer, its prostate habit, as well as its hardiness and the minimal maintenance it requires. It has little problem with both disease and insects. They do require partial shade, however, and they perform best when given about 4 hours of sunlight. The plants can be cut to 20 cm (8 inches) in the spring in order to delay flowering and increase the number of branches. It is marginally hardy in USDA zone
3, and fully hardy from zones 4 to 8. It is commonly available in North American nurseries and several cultivars have been selected, including:
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. It occurs in the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, primarily in the Appalachian mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
, though it is also present in southeastern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, but only in about 25 populations in the provinces of Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
and Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
. In the U.S. it is abundant and common, but in Canada it is considered threatened due to its restricted distribution. It can be found in dry open woods as well as along wood-edges and clearings. The species is distinguished by its flower heads that have yellow centers and white rays that are arranged in flat-topped corymbiform arrays, emerging in the late summer through fall. Other distinguishing characteristics include its serpentine stems and sharply serrated narrow heart-shaped leaves. It is very similar to and often confused with E. chlorolepis
Eurybia chlorolepis
Eurybia chlorolepis, commonly known as the Mountain Wood Aster or Appalachian Heartleaf Aster, is a herbaceous perennial native to the southeastern United States. It is present only at relatively high elevations in the Appalachian mountains...
, E. schreberi
Eurybia schreberi
Eurybia schreberi, commonly called Schreber's Aster, is a perennial herb in the composite family. It is native to eastern North America, where it is present in Canada and the United States. The flowers emerge in the late summer or early fall to show white ray florets and yellow disc florets...
and Symphyotrichum cordifolium
Symphyotrichum cordifolium
Symphyotrichum cordifolium, commonly known as the Heartleaf Aster or Common Blue Wood Aster, is an herbaceous perennial native to eastern North America, where it is present from Manitoba in Canada, east to Nova Scotia and south through the United States to Georgia...
, though E. schreberi differs in having wider leaves with more teeth, while E. chlorolepis has more rays, longer involucre
Involucre
Involucre may refer to* involucral bract, a bract, bract pair, or whorl of bracts surrounding a flower or inflorescence* a term sometimes misused for the cupule surrounding developing nuts in the Fagaceae...
s, and only occurs in the southern U.S. from Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
to Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
. The white wood aster is sometimes used in cultivation in both North America and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
due to it being quite tough and for its showy flowers.
Description
E. divaricata is a late summer to fall-flowering herbaceous perennial, typically growing to heights between 30 and 90 cm, though some specimens may be up to 1.2 metres tall. The plant emerges each year from rhizomeRhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s and forms dense colonies
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
of clones
Clonal colony
A clonal colony or genet is a group of genetically identical individuals that have grown in a given location, all originating vegetatively from a single ancestor. In plants, an individual in such a population is referred to as a ramet...
that lack sterile rosettes. The rhizomes are branched, elongated and become woody with age. One simple erect stem is present per plant. It is flexible and nearly hairless to finely hairy near the base, though densely covered with fine hair towards the extremities.
Three types of leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
with differing morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
are present: cauline leaves, or those that appear on the stem from the middle of the plant upwards; basal leaves, or those that are present at the base of the plant; and distal leaves, which are those found on the extremities of the plant. All types are thin and sharply serrated with 6 to 15 pointed teeth per side. They are ciliate, meaning they have small hairy projections emerging from the margins of the leaf, while the apices, or tips of the leaves, are acuminate, meaning they taper to a point. The adaxial (i.e. upper) surfaces of the leaves are nearly hairless or sparsely hairy, while the abaxial (i.e. lower) surfaces are sparsely hairy with the veins being more villous, or covered in shaggy hairs.
The basal leaves are ovate, or egg-shaped, with bases that are cordate, or heart-shaped. The blades measure 1.9 to 6.5 cm in length by 1.7 to 6 cm in width and have petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
s ranging in length from 2 to 7 cm. They wither when the plant flowers. The cauline leaves have petioles measuring 2.5 to 7 mm long that are often winged. Their blades are also ovate, though the bases may be cordate to rounded. They measure 2 to 20 cm long by 1 to 10 cm wide, making them often much longer than the basal leaves. The distal leaves are typically sessile
Sessility (botany)
In botany, sessility is a characteristic of plants whose flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel...
, meaning that no petiole is present, though they are sometimes subpetiolate, meaning a very short petiole is present. The blades are ovate to lanceolate, meaning lance-shaped, with rounded bases and are 0.5 to 2 cm long by 0.1 to 0.8 cm wide.
The capitula
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
, or flower heads, are arranged in relatively flat-topped corymbiform arrays. The capitula number anywhere from 4 to 50 and up to 100 or more in exceptional cases. The peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
s, i.e. the flower stalks, are up to 1.5 cm in length and are densely covered with non-gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
ular hairs. Bracts, modified leaves that appear at the axil of a peduncle, are typically absent, though in some cases up to two are present. The involucre
Involucre
Involucre may refer to* involucral bract, a bract, bract pair, or whorl of bracts surrounding a flower or inflorescence* a term sometimes misused for the cupule surrounding developing nuts in the Fagaceae...
s, which are the whorls of small, scale-like modified leaves that appear at the base of the capitulum, are in between cylindric and campanulate (i.e. bell-shaped) in shape and measure 4.2 to 6 mm long, making them much shorter than the pappi
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
.
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....
glands. Their chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
ous zones, a darker green zone where chlorophyll is concentrated, appear on the upper half of the outer phyllaries, to the upper third or along the outer midveins of the inner phyllaries. The outer phyllaries typically measure 0.7 to 1.5 mm wide with the lengths rarely exceeding 2.5 times the width.
As with most members of the composite family
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
, the actual flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s appear in two different froms: as ray florets, which have strap-like appendages that look like petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s and project around the outside of the capitulum, and as disc florets, which appear at the center of the flower head and are very small. The ray florets number between 5 and 10, though as many as 12 may be present. Their straps are white and measure 6 to 12 mm long by 1.5 to 2.2 mm wide. The disc florets number from 12 to 19 and up to 25 and have yellow corollas (i.e. petals, though they are fused into a tube) that are 4.1 to 4.8 and exceptionally 5.5 mm long. Their corollas are abruptly ampliate, or enlarged, with tubes that are longer than their campanulate throats. The tubes measure 2.3 to 2.6 mm while the throats are typically only 0.9 to 1.2 mm long. The lobes, i.e. the friges of the throat, are reflexed and lanceolate in shape, measuring 0.7 to 1.4 mm.
The fruit are cypselae, a type of achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
, which are brown in colour, slightly compressed and are between cylindric and obovoid, or inversely egg-shaped. They are between 2.6 and 3.8 mm in length and sparsely strigillose, or set with stiff bristly hairs, with 7 to 10 ribs, which themselves are tan to stramineous (i.e. straw-coloured). The pappi
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
, which are modified sepals, are made up of reddish to cream-coloured bristles that are 3.7 to 5 mm long, making them equal to or longer than the disc corollas in length. The bristles are fine and barbellulate, or barb-like, though they may be sometimes more or less clavate, or club-shaped, towards their apices.
Similar species
Several different plants are superficially quite similar to the white wood aster, but close examination as well as knowledge of the plants' differing habitats and ranges can readily distinguish them. The most similar species is the mountain wood aster (Eurybia chlorolepisEurybia chlorolepis
Eurybia chlorolepis, commonly known as the Mountain Wood Aster or Appalachian Heartleaf Aster, is a herbaceous perennial native to the southeastern United States. It is present only at relatively high elevations in the Appalachian mountains...
), which was previously considered conspecfic with E. divaricata. E. chlorolepis differs in having flower stalks that are longer than 1.5 cm, while those of E. divaricata are shorter than this. The involucre
Involucre
Involucre may refer to* involucral bract, a bract, bract pair, or whorl of bracts surrounding a flower or inflorescence* a term sometimes misused for the cupule surrounding developing nuts in the Fagaceae...
s of the mountain wood aster are generally between 6.5 and 9 mm in length, while those of the white wood aster are normally from 4.2 to 6.5 mm long, but in rare cases they may be as long as 7.5 mm. The mountain wood aster almost always has more rays than the white wood aster: the former usually has 12 to 16, but occasionally as few as 10, while the latter generally has 5 to 10 and never more than 12. The rays are also longer on the mountain wood aster at 17 to 18 mm in most cases, while the white wood aster's are generally only 10 to 15 mm. Lastly, E. chlorolepsis is only present from southern Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
south to Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
in the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
at altitudes of 1200 to 2000 metres, while E. divaricata can be found from southern Canada south to Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, meaning their ranges only overlap in the southern United States, and there only at high elevations.
Another species commonly confused with the white wood aster is Schreber's aster (Eurybia schreberi
Eurybia schreberi
Eurybia schreberi, commonly called Schreber's Aster, is a perennial herb in the composite family. It is native to eastern North America, where it is present in Canada and the United States. The flowers emerge in the late summer or early fall to show white ray florets and yellow disc florets...
). Schreber's aster is typically found on moister soils, though it can also be found on mesic
Mesic
Mesic may refer to:* Mesic, North Carolina, a town in the United States* Mesic habitat, a type of habitat...
sites. While much of their ranges overlap, Schreber's aster is not found south of Virginia or Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
. Schreber's aster can also be distinguished by the more numerous teeth on the leaves, typically numbering 15 to 30 per side to the white wood aster's 6 to 15 per side. The leaves are wider on Schreber's aster with broader sinuses at the bases. The flower stalks are also densely hairy on the white wood aster, while they are only sparsely haired on Schreber's aster. Lastly, the clones
Clonal colony
A clonal colony or genet is a group of genetically identical individuals that have grown in a given location, all originating vegetatively from a single ancestor. In plants, an individual in such a population is referred to as a ramet...
of E. schreberi have sterile rosettes, while those of E. divaricata do not.
Two more superficially similar plants include the bigleaf aster (Eurybia macrophylla
Eurybia macrophylla
Eurybia macrophylla, commonly known as the Bigleaf Aster, Largeleaf Aster or Largeleaf or Bigleaf Wood Aster, is an herbaceous perennial in the composite family that was formerly treated in the genus Aster...
) and the heartleaf aster (Symphyotrichum cordifolium
Symphyotrichum cordifolium
Symphyotrichum cordifolium, commonly known as the Heartleaf Aster or Common Blue Wood Aster, is an herbaceous perennial native to eastern North America, where it is present from Manitoba in Canada, east to Nova Scotia and south through the United States to Georgia...
), though both usually have blue or pale blue rays, while those of E. divaricata are always white. Both species sometimes have white rays in rare cases, but E. macrophylla can still be distinguished by its larger and broader leaves and S. cordifolium by its straighter and branched stems.
Distribution and habitat
E. divaricata is present primarily in the Appalachian mountains in eastern North America. It can be found on dry to mesicMesic habitat
In ecology, a mesic habitat is a type of habitat with a moderate or well-balanced supply of moisture, e.g., a mesic forest, a temperate hardwood forest, or dry-mesic prairie. Compared to a dry habitat, a mesic habitat is moister....
sites in eastern deciduous and mixed deciduous woods as well as on edges, clearings, and roadsides. It is most common at altitudes ranging from 0 to 1200 metres, though it can be found as high as 1700 metres. In Canada it is present in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
and Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
, while in the United States it can be found in all states east of and including Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...
, Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
and Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, but excluding Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. It also has been introduced to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, particularly to the Netherlands.
The species is known from only 25 locations in Canada, and is considered threatened.
Cultivation
While the white wood aster does not compare in popularity to the other cultivated asters, such as the New England asterNew England Aster
Symphyotrichum novae-angliae , commonly known as the New England Aster, is an herbaceous perennial in the composite family...
, it does have its niche, especially in North American native gardens. The plant flowers earlier than many other asters, does not require any staking to support it and flowers well in shade. It is attractive to gardeners due to its showy white flowers that emerge in mid to late summer, its prostate habit, as well as its hardiness and the minimal maintenance it requires. It has little problem with both disease and insects. They do require partial shade, however, and they perform best when given about 4 hours of sunlight. The plants can be cut to 20 cm (8 inches) in the spring in order to delay flowering and increase the number of branches. It is marginally hardy in USDA zone
Hardiness zone
A hardiness zone is a geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions, including its ability to withstand the minimum temperatures of the zone...
3, and fully hardy from zones 4 to 8. It is commonly available in North American nurseries and several cultivars have been selected, including:
- 'Fiesta', which has leaves streaked with white, giving the effect of confetti, and flowers that are light lavender. The selection was made in Waseca, MinnesotaMinnesotaMinnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
. - 'Raiche Form', which has white flowers that are larger than usual and darker, thin, sinewy stems. The cultivar was found by Roger Raiche.
- 'Snow Heron', which has white flowers and dark green leaves splotched and streaked with white. The cultivar was selected from a chance seedlingChance seedlingA chance seedling is a plant that is the product of unintentional breeding. It may be a genetically unique individual with desirable characteristics that is then intentionally bred. Plants that come from the artificial union of gametes from a maternal and paternal source are not chance...
grown at the Heronswood Nursery in Washington.