Index of Species Information
SPECIES: Rhododendron calendulaceum
Introductory
SPECIES: Rhododendron calendulaceum
AUTHORSHIP AND CITATION :
Carey, Jennifer H. 1994. Rhododendron calendulaceum. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
https://www.fs.usda.gov/database/feis/plants/shrub/rhocal/all.html [].
ABBREVIATION :
RHOCAE
SYNONYMS :
Azalea calendulacea Michx. [8,20]
SCS PLANT CODE :
RHCA4
COMMON NAMES :
flame azalea
TAXONOMY :
The currently accepted scientific name for flame azalea is Rhododendron
calendulaceum (Michx.) Torr. (Ericaceae) [8,20]. There are no currently
accepted infrataxa.
LIFE FORM :
Shrub
FEDERAL LEGAL STATUS :
See OTHER STATUS
OTHER STATUS :
The status of flame azalea in New York and Maryland is undetermined.
Although historically reported in these states, no extant populations
are known [3,30]. Flame azalea is listed as endangered in Ohio [13].
It is secure throughout the rest of its range.
DISTRIBUTION AND OCCURRENCE
SPECIES: Rhododendron calendulaceum
GENERAL DISTRIBUTION :
Flame azalea occurs in the Appalachian Mountains from southern
Pennsylvania and southeastern Ohio south to northern Georgia and
northern Alabama [8,20,28]. Historically it has been reported as far
north as southeastern New York [30].
ECOSYSTEMS :
FRES13 Loblolly - shortleaf pine
FRES15 Oak - hickory
FRES18 Maple - beech - birch
STATES :
AL GA KY NC OH PA SC TN VA WV
BLM PHYSIOGRAPHIC REGIONS :
NO-ENTRY
KUCHLER PLANT ASSOCIATIONS :
K104 Appalachian oak forest
K109 Transition between K104 and K106
K111 Oak - hickory - pine forest
SAF COVER TYPES :
44 Chestnut oak
52 White oak - black oak - northern red oak
53 White oak
55 Northern red oak
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Flame azalea occurs in mixed deciduous forests [11,19,26]. It occurs in
the well developed shrub layer of oak (Quercus spp.) forests of southern
and western exposures, and with more mesic site species in ravines.
Flame azalea is an important understory shrub in forests formerly
codominated by American chestnut (Castanea dentata) [1,26].
Flame azalea occurs with other ericaceous shrubs including rosebay
rhododendron (Rhododendron maximum), mountain-laurel (Kalmia latifolia),
highbush cranberry (Vaccinium corymbosum), and huckleberry (Gaylussacia
spp.) [1]. It occurs at low coverage in the grassy bald vegetation type
and the grassy bald edge ecotone [26].
MANAGEMENT CONSIDERATIONS
SPECIES: Rhododendron calendulaceum
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
NO-ENTRY
PALATABILITY :
NO-ENTRY
NUTRITIONAL VALUE :
NO-ENTRY
COVER VALUE :
NO-ENTRY
VALUE FOR REHABILITATION OF DISTURBED SITES :
NO-ENTRY
OTHER USES AND VALUES :
Flame azalea is considered one of the finest ornamental shrubs in the
United States [14].
OTHER MANAGEMENT CONSIDERATIONS :
Many nursery cultivars have been developed from flame azalea. It is
highly sought after for its striking colors and relative cold hardiness
[17,18]. In states where flame azalea is rare, illegal collection is a
threat [13].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Rhododendron calendulaceum
GENERAL BOTANICAL CHARACTERISTICS :
Flame azalea is a native, deciduous, erect, much-branched shrub that
grows to 10 feet (3 m) in height. Its morphology and phenology are
highly variable [28]. The fruit is a capsule [8,20,29]. Rhododendrons
(Rhododendron spp.) have a diffuse shallow root system [22]. Flame
azalea is not rhizomatous [8].
RAUNKIAER LIFE FORM :
Phanerophyte
REGENERATION PROCESSES :
Rhododendron fruits split along the sides soon after ripening and
release many small seeds which are disseminated short distances by
wind. Moist mineral soil or a short moss seedbed is required for
seedling establishment [9,16].
Rhododendrons sprout from the root crown when top-killed [9].
Propagation techniques from cuttings are described [5,23]. Day-night
temperatures and durations for maximizing flame azalea seedling growth
are reported [12].
SITE CHARACTERISTICS :
Flame azalea occurs on south- and west-facing slopes of mountainous
sites. It occurs on submesic to subxeric sites at lower elevations and
on submesic sites at elevations above 5,000 feet (1,500 m) [26].
Adequate humidity and soil moisture are required. Rhododendrons grow
best on acidic soils from pH 4.5 to 5.5 [4].
SUCCESSIONAL STATUS :
Facultative Seral Species
Flame azalea is intermediate in shade tolerance. It grows well in the
indirect light of open woods but declines as forests mature and canopies
close [13].
SEASONAL DEVELOPMENT :
Flame azalea flowers in late April and May at lower elevations and in
June and early July at higher elevations [28]. Flowers appear before or
with the leaves and last several weeks. Fruit matures July through
September [2,8,20,29].
FIRE ECOLOGY
SPECIES: Rhododendron calendulaceum
FIRE ECOLOGY OR ADAPTATIONS :
Flame azalea is probably fire resistant because of its ability to sprout
from the root crown. Fire may open up maturing forest canopies and
rejuvenate declining flame azalea. Flame azalea occurs in oak woods
that periodically experience fire [27].
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".
POSTFIRE REGENERATION STRATEGY :
Tall shrub, adventitious-bud root crown
FIRE EFFECTS
SPECIES: Rhododendron calendulaceum
IMMEDIATE FIRE EFFECT ON PLANT :
Rhododendrons are sensitive to fire [9]. Fire probably top-kills
flame azalea.
PLANT RESPONSE TO FIRE :
Flame azalea probably sprouts from the root crown when top-killed.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
The Research Project Summary Early postfire effects of a prescribed
fire in the southern Appalachians of North Carolina provides information
on prescribed fire
and postfire response of plant community species,
including flame azalea,
that was not available when this species review
was originally written.
FIRE MANAGEMENT CONSIDERATIONS :
NO ENTRY
REFERENCES
SPECIES: Rhododendron calendulaceum
REFERENCES :
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FEIS Home Page
https://www.fs.usda.gov/database/feis/plants/shrub/rhocae/all.html
