Rhododendron calendulaceum

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Flame azalea
Rhododendron calendulaceum.jpg
At Craggy Gardens, North Carolina
Status TNC G5.svg
Secure  (NatureServe) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Ericaceae
Genus: Rhododendron
Subgenus: Rhododendron subg. Hymenanthes
Section: Rhododendron sect. Pentanthera
Species:
R. calendulaceum
Binomial name
Rhododendron calendulaceum
Synonyms [2]
Synonymy
  • Azalea calendulaceaMichx.
  • Azalea pontica var. calendulacea(Michx.) Pers.
  • Azalea aurantiacaF.Dietr.
  • Azalea calendulacea var. croceaMichx.
  • Azalea coccinea aurantiaLodd.
  • Azalea crocea(Michx.) Hoffmanns.
  • Azalea jammeaPritz.
  • Azalea nudiflora var. aurantiaca(F.Dietr.) Dum.Cours.
  • Azalea nudiflora var. coccinea-majorDum.Cours.
  • Azalea nudiflora var. hirtaElliott
  • Azalea speciosa var. aurantia(Lodd.) DC.
  • Azalea speciosa var. aurantiaca(F.Dietr.) G.Kirchn.
  • Rhododendron calendulaceum f. aurantiacum(F.Dietr.) Zabel
  • Rhododendron calendulaceum f. aurantium(Lodd.) Rehder
  • Rhododendron calendulaceum f. croceum(Michx.) Rehder
  • Rhododendron calendulaceum var. croceum(Michx.) Sweet
  • Rhododendron luteumC.K.Schneid.
  • Rhododendron luteum var. croceum(Michx.) C.K.Schneid.
  • Rhododendron speciosum var. aurantium(Lodd.) Sweet

Rhododendron calendulaceum, the flame azalea, [3] is a species of Rhododendron. It is a deciduous shrub that grows up to 120–450 cm tall. This species of Rhododendron is native to the Appalachian Mountains in the eastern United States, ranging from southern Pennsylvania and Ohio to northern Georgia. It may be extirpated from Pennsylvania and Alabama. [4] It occurs naturally in mixed deciduous forests and is typically found in woodland slopes and mountain balds in the Appalachians, [5] where it prefers dry and rocky mountain woods. [6] The inflorescences of Rhododendron calendulaceum are visited by many animals such as bees, butterflies, hummingbirds and small mammals. [5] It is a popular cultivated plant due to its bright yellow, orange or red flowers.

Description

It is a deciduous shrub, 120–450 cm tall. The leaves are simple, 3–7 cm long, slightly dull green above and villous below. The arrangement is generally alternate, however they appear whorled towards the tips of the branches.

The flowers are 4–5 cm long, usually bright orange, but can vary from pastel orange to dark reddish-orange. These non-fragrant flowers have 4-5 lobes and grow in clusters of 5–10. It typically blooms in late May and early June. [5] [7]

Variation in wild populations

Rhododendron calendulaceum is a highly variable species. The flowers of Rhododendron calendulaceum can range from light yellow to orange and rarely, a scarlet red. Some flowers appear to be a blend of multiple colors, and others seem to have secondary pigments such as pink or red. Some have even reported a white flower in Rhododendron calendulaceum, however these records cannot be verified. The buds of Rhododendron calendulaceum are typically a darker color than the mature flower, however some flowers deepen in color with age. In some plants, a full range of colors such as yellows, oranges and reds can be present on the same plant. It is possible that color change is affected by light, with flowers in shadier areas exhibiting less color change compared to plants in open spaces. [8]

The flower sizes in Rhododendron calendulaceum are also variable, with a typical flower size of 2-2.5 inches. Some flowers have blossoms of less than an inch, while others can be up to 3 inches. [8]

Ecology

The inflorescences of Rhododendron calendulaceum are visited by a diverse group of animals such as bees, butterflies, hummingbirds and small mammals. [5] The flowers can only be pollinated by the wings of butterflies. Only Papilio glaucus and Speyeria cybele have been observed pollinating the flowers. P. glaucus is more effective in pollination due to differences in wing flapping behavior. [9] Rhododendron calendulaceum is a host of the fungus Exobasidium vaccinii . E. vaccinii negatively affects the reproduction and health of the flowers and branches of Rhododendron calendulaceum. [10] The insect Rhinocapsus vanduzeei is known to feed on the stamens of Rhododendron calendulaceum flowers. [11] Rhododendron calendulaceum is a host plant for the larvae of Euura lipovskyi . [12]

Distribution and habitat

This species of Rhododendron is native to the Appalachian Mountains in the eastern United States, ranging from southern Pennsylvania and Ohio to northern Georgia. It may be extirpated from Pennsylvania and Alabama. [4] The state of Pennsylvania lists Rhododendron calendulaceum as extirpated from the state. [13] It has been reported historically in New York and Maryland, however, its current native status in these states is undetermined. [14] However, it can occur as an introduced species in anthropogenic habitats. It occurs naturally in mixed deciduous forests. It is typically found in woodland slopes and mountain balds in the Appalachians, [5] where it prefers dry and rocky mountain woods. [6] It lives in a variety of forest ecosystems such as Loblolly-shortleaf pine, oak-hickory and maple-beech-birch forests. It prefers to be covered by Quercus montana , Quercus alba , Quercus velutina and Quercus rubra . Rhododendron calendulaceum primarily occurs in mixed deciduous forests. It is found in the well-developed shrub layer of oaks with southern and western sun exposure. It is commonly found in ravines with mesic soil. Rhododendron calendulaceum is an important understory shrub in forests that were formerly co-dominated by the American chestnut. Rhododendron calendulaceum commonly occurs with other ericaceous shrubs including Rhododendron maximum , Kalmia latifolia , Vaccinium corymbosum , and Gaylussacia spp. Rhododendron calendulaceum commonly occurs in oak forest that periodically see fire. [15] Rhododendron calendulaceum grows in well-drained, mesic to moist, medium to fine textured soils in part shade. Rhododendron calendulaceum prefers a pH range of 4.3 to 5.8. Rhododendron calendulaceum requires a minimum soil depth of 14 in. Rhododendron calendulaceum requires at least a 200 day growing season. [16]

Rhododendron calendulaceum in the shrub layer under oaks Rhododendron calendulaceum in Lumpkin county, GA.jpg
Rhododendron calendulaceum in the shrub layer under oaks

Horticulture

The flame azalea is a popular cultivated plant, primarily due to its showy flowers. Many cultivars and domestic varieties exist, including Chattooga, Cherokee, Golden Sunset Flame, Golden Yellow Flame, Smokey Mountaineer and Wahsega. [7] It is also an important parent species in hybrid Azaleas, such as Ghent, Knap Hill, Maid in the Shade, Mollis and Northern Lights. [17]

See also

Related Research Articles

<i>Rhododendron</i> Genus of flowering plants in the heath family Ericaceae

Rhododendron is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are native to eastern Asia and the Himalayan region, but smaller numbers occur elsewhere in Asia, and in North America, Europe and Australia.

<span class="mw-page-title-main">Appalachian Mountains</span> Mountain range in eastern North America

The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain. The general definition used is one followed by the United States Geological Survey and the Geological Survey of Canada to describe the respective countries' physiographic regions. The U.S. uses the term Appalachian Highlands and Canada uses the term Appalachian Uplands; the Appalachian Mountains are not synonymous with the Appalachian Plateau, which is one of the provinces of the Appalachian Highlands.

<i>Rhododendron atlanticum</i> Species of flowering bush

Rhododendron atlanticum, the dwarf azalea or coastal azalea, is a species of Rhododendron native to coastal areas of the eastern United States, from New Jersey south to Georgia.

<span class="mw-page-title-main">Northeastern coastal forests</span> Temperate broadleaf and mixed forest ecoregion of the United States

The Northeastern coastal forests are a temperate broadleaf and mixed forests ecoregion of the northeast and middle Atlantic region of the United States. The ecoregion covers an area of 34,630 sq miles (89,691 km2) encompassing the Piedmont and coastal plain of seven states, extending from coastal southwestern Maine, southeastern New Hampshire, eastern Massachusetts, and Rhode Island, southward through Connecticut, New York State, New Jersey, southeast Pennsylvania, Delaware and Maryland.

The Edith J. Carrier Arboretum is an arboretum and botanical garden on the James Madison University campus, located in Harrisonburg, Virginia, United States in the Shenandoah Valley. Groundbreaking for the arboretum took place April, 1985, under direction of Dr. Norlyn Bodkin,[1] who is credited the first scientific botanical discovery along the Eastern Seaboard of Virginia since the 1940s, Trillium: Shenandoah Wake Robin, presently found at the arboretum[2]. The only arboretum located on the campus of a Virginia state university. Exhibits include a developed trail system through 125 acres (0.51 km2) of mature Oak-Hickory Forrest with two identified century specimens and a species on the U.S. Fish and Wildlife Threatened Species list protected at the arboretum: Betula uber, Round-Leaf Birch.[3]

<span class="mw-page-title-main">Appalachian mixed mesophytic forests</span> Temperate broadleaf and mixed forests ecoregion of the United States

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<i>Rhododendron occidentale</i> Species of plant

Rhododendron occidentale, the western azalea or California azalea, is one of two deciduous Rhododendron species native to western North America. The western azalea is known to occur as far north as Lincoln and Douglas Counties in Oregon and as far south as the mountains of San Diego county. Typically found in the coastal ranges of western North America, it also grows in the Cascade and Sierra Nevada mountain ranges, but is not known east of them.

<span class="mw-page-title-main">Appalachian–Blue Ridge forests</span> Temperate broadleaf and mixed forests ecoregion of the United States

The Appalachian–Blue Ridge forests are an ecoregion in the Temperate broadleaf and mixed forests Biome, in the Eastern United States. The ecoregion is located in the central and southern Appalachian Mountains, including the Ridge-and-Valley Appalachians and the Blue Ridge Mountains. It covers an area of about 61,500 square miles (159,000 km2) in: northeast Alabama and Georgia, northwest South Carolina, eastern Tennessee, western North Carolina, Virginia, Maryland, and central West Virginia and Pennsylvania; and small extensions into Kentucky, New Jersey, and New York.

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The Great Balsam Mountains, or Balsam Mountains, are in the mountain region of western North Carolina, United States. The Great Balsams are a subrange of the Blue Ridge Mountains, which in turn are a part of the Appalachian Mountains. The most famous peak in the Great Balsam range is Cold Mountain, which is the centerpiece of author Charles Frazier's bestselling novel Cold Mountain.

<span class="mw-page-title-main">Cove (Appalachian Mountains)</span> Small valley in the Appalachian Mountains between two ridge lines

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An oak–heath forest is a plant community association and type of forest ecology. It is a deciduous forest type of well-drained, acidic soils, characterized by oaks (Quercus) and plants of the heath family (Ericaceae). It is commonly found in the high elevations of the eastern United States. Such forest areas typically have a dense fibrous root layer at the surface of the soil, and in many areas predominate on south-facing or southwest-facing slopes. Many of the existing oak–heath forests once featured American chestnut as an important canopy species.

<i>Rhododendron arborescens</i> Species of flowering plant

Rhododendron arborescens, also known as smooth azalea or sweet azalea, is a species of flowering plant in the family Ericaceae, native to the eastern seaboard of the United States.

<i>Rhododendron austrinum</i> Species of plant

Rhododendron austrinum is a species of flowering plant in the heath family known by the common names Florida flame azalea, honeysuckle azalea, southern yellow azalea, and orange azalea. It is native to the southern United States, where it can be found in Alabama, Florida, Georgia, and Mississippi. It is also a common ornamental plant.

<i>Rhododendron vaseyi</i> Species of flowering plant

Rhododendron vaseyi is a species of flowering plant in the heath family known by the common name pinkshell azalea. It is endemic to the Appalachian highlands of North Carolina in widely scattered locations. While there is a main center of distribution west of Asheville, there is also a large population on Grandfather Mountain, in the northwestern corner of the state.

The Central and southern Appalachian montane oak forest is a forest system found in the Appalachian Mountains of West Virginia, Virginia, Kentucky, Tennessee, North Carolina, South Carolina, and Georgia.

The Appalachian hemlock–northern hardwood forest is a forest system found in the Appalachian Mountains of New Hampshire, Vermont, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Maryland, Virginia, Eastern Kentucky, West Virginia and western North Carolina. These forests occur in deep coves, moist flats, and ravines.

The northeastern interior dry–mesic oak forest is a forest system found in Maine, Vermont, New Hampshire, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Ohio, Pennsylvania, Maryland, Virginia, and West Virginia. These forests cover large areas at low and middle elevations, typically on flat to gently rolling terrain.

<i>Clethra acuminata</i> Species of flowering plant

Clethra acuminata, the mountain pepper bush, is a shrub native to the Appalachian Mountains of the southeastern United States. It has been reported from the states of Pennsylvania, West Virginia, Virginia, North Carolina, South Carolina, Georgia, Alabama and Tennessee, primarily from deciduous forests at elevations of 500–1,400 m (1,600–4,600 ft).

<span class="mw-page-title-main">North American azaleas</span>

North American azaleas are flowering shrubs in the genus Rhododendron, section Pentanthera, subsection Pentanthera, so named because they all have five stamens. Most are in the United States, with one species found in Canada and one being found in Mexico. North American azaleas are commonly confused with azaleas of Asian origin, the evergreen azaleas. North American azaleas are deciduous and produce two types of buds. One is a larger and produces about 20 flowers while the other bud produces a leafy shoot. The flower color, fragrance, and number of stamens vary among species.

References

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  10. Wolfe, Lorne M.; Rissler, Leslie J (January 2000). "Reproductive consequences of a gall-inducing fungal pathogen (Exobasidium vaccinii) on Rhododendron calendulaceum (Ericaceae)". Canadian Journal of Botany. 77 (10). doi:10.1139/b99-108 . Retrieved 19 December 2023.
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  12. Goulet, Henri; Catling, Paul; Kostiuk, Brenda. "First record of Azalea Sawfly (Euura lipovskyi, Hymenoptera: Tenthredinidae) in Canada". The Canadian Field-Naturalist. doi: 10.22621/cfn.v136i1.2859 . Retrieved 25 April 2024.
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  15. "SPECIES: Rhododendron calendulaceum". www.fs.usda.gov. Fire Effects Information System. Retrieved 20 December 2023.
  16. Mehl, Geoffrey (2016). Pennsylvania Naturally. Pennystone Books. p. 352. ISBN   9780986276606.
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