National Collection of Imperiled Plants

CPC National Collection Plant Profile

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Tom Ward

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CPC National Collection Plant Profile

Rhododendron vaseyi

Family:	Ericaceae
Common Names:	pinkshell azalea, pink-shell Azalea
Author:	Gray
Growth Habit:	Shrub
CPC Number:	3739

Distribution
Protection
Conservation
References

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Photographer: Tom Ward

Rhododendron vaseyi is Fully Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

The Arnold Arboretum of Harvard University

Irina Kadis contributed to this Plant Profile.

Rhododendron vaseyi

Rhododendron vaseyi is a deciduous, upright narrow shrub that can grow to 5 meters in height with appealing erect branches (Wilson and Rehder 1921, Cox 1990) Its root system is compact and shallow. Scentless, pinkish white flowers begin blooming in April and are thought to attract hummingbirds (Radford et al. 1968, Dirr 1998, Hightshoe 1988, Foote and Jones 1994).
This peculiar endemic of the Blue Ridge was found in 1878 in western North Carolina by G. R. Vasey, son of the government botanist, G. Vasey, and named after its discoverer (Bensley 2002). The first plant was acquired for cultivation by the Arnold Arboretum in 1880.

Distribution & Occurrence

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State Range

North Carolina

Habitat

R. vaseyi grows in mountain ravines, swamps, bogs, banks of streams, coniferous and oak forests at high elevations (3,000-5,500 ft) (Foote and Jones 1994). R. vaseyi appears to spread to clearings at places where the forest overstory has been logged. Therefore, logging does not constitute an immediate threat.
It was once found in the wild in Massachusetts, near Halifax, where it appeared to be naturalized on the territory of an abandoned nursery in a swamp as well as on sandy soil. (Wilson and Rehder 1921).

Distribution

Historically, this species was found only in six sites in the mountains of North Carolina (Radford et al. 1968). It is now known from the Blue Ridge from Ashe County south to Macon County, Transylvania County in western North Carolina and Balsam Mountain near Webster in Jackson County, western North Carolina (Cox 1990, Foote and Jones 1994, Dirr 1998.)

Number Left

Individual numbers are unknown.

Protection

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Global Rank:	G3	4/10/2009	Guide to Global Ranks
Federal Status:	RT		Guide to Federal Status
Recovery Plan:	No

State/Area Protection

State/Area	Rank	Status	Date

Conservation, Ecology & Research

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Ecological Relationships

Ecological relationships are unknown.

Threats

� The main danger comes from irresponsible and uncontrolled development of vacation and retirement housing.
� Bog drainage results in total destruction of habitats.
� Amateur gardeners and nurserymen illegally collect plants from the wild, which is one more cause of population decrease.

Current Research Summary

Schreiber et al. (2000) conducted a genetic study of 15 currently recognized species in Rhododendron L. section Pentanthera G. Don. and found that they were all closely related.

Current Management Summary

There is no formal management plan.

Research Management Needs

Management needs include assessing and monitoring populations as well as devising a conservation plan that would offer protection for this plant.

Ex Situ Needs

One of the hardy American rhododendrons, very shade tolerant, also tolerant of soil compaction, poor drainage, and floods. It demands wet to moist growing conditions and strongly to moderately acid soil reaction (4.5-6.0). However, once established, pinkshell azalea can tolerate a wide variety of conditions and even survive droughts. Having been cultivated in the Arnold Arboretum since 1880, it proved to be hardy in Boston and is valued for cultivation all over the USA and in Europe. The flowers are frost resistant, so that it is successfully grown in Scandinavia.

Cultivars: 'White find' is originating from a wild-collected form with white flowers. Another form with white flowers, f. album, was found among seedlings grown at the Arnold Arboretum and also at Kew Gardens and was used for the cultivar 'Album'. 'Suva' has pink flowers.

Apparently, R. vaseyi does not hybridize and stays stable when grown from seed. Propagation from seed: sow into milled Sphagnum, maintain humidity under cover, water carefully. Seedlings are tiny and growing slowly. Put them a few per pot first, to reduce the risk of overwatering; repot once they achieve sufficient size.

Propagation from softwood cuttings: take cuttings in May-June, keep them under fog or mist in 50/50 sand-perlite. With 2,500-5,000 ppm K-IBA or H # 3 treatment, the rooting rate is 70-80%. Cuttings become more secure once they survive through the first winter.

References

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Books (Single Authors)

Cox, P.A. 1990. The Larger Rhododendron species. Oregon: Revised Ed. Timber Press.

Dirr, M.A. 1998. Manual of Woody Landscape Plants. Champaign, Illinois: Stipes Publishing L. L. C.

Foote, L.E.; Jones, S.B., Jr. 1994. Native Shrubs and Woody Vines of the Southeast. Oregon: Timber Press.

Hightshoe, G.L. 1988. Native Trees, Shrubs, and Vines for Urban and Rural America. New York: Van Nostrand Reinhold.

Radford, A.E.; Ahles, H.E.; Bell, C.R. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: University of North Carolina Press. 1183p.

Weakley, A.S. 2002. Flora of the Carolinas and Virginia, Working Draft. Unpublished--available on-line.

Wilson, E.H.; Rehder, A. 1921. A monograph of azaleas. Rhododendron subgenus Anthodendron. Publications of the Arnold Arboretum, No. 9. Cambridge, Massachusetts: The University Press.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Electronic Sources

(2000). Showy Native Trees, Shrubs and Woody Vines. [Web site] NC State University. http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/native/scientific_namea-e.html. Accessed: 2002.

Bensley, E. (2002). Species In Our Midst: Rhododendron vaseyi. The American Rhododendron Society, Massachusetts Chapter. http://www.rosebay.org/chapterweb/specvaseyi.htm. Accessed: 2002.

Hyatt, D.W. (2001). East Coast Native Azaleas. [Web site] Middle Atlantic Chapter ARS Species Study Group. http://www.tjhsst.edu/~dhyatt/azaleas/index.html. Accessed: 2002.

Journal Articles

Judd, W.S.; Kron, K.A. 1995. A revision of Rhododendron: VI. Subgenus Pentanthera (sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany. 52, 1: 1-54.

Scheiber, S.M.; Jarret, R.L.; Robacker, C.D.; Newman, M. 2000. Genetic relationships within Rhododendron L. section Pentanthera G. Don based on sequences of the internal transcribed spacer (ITS) region. Scientia Horticulturae. 85, 1-2: 123-135.

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This profile was updated on 3/4/2010