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Naming Genus



Species In Our Midst
Rhododendron prinophyllum

by Elizabeth Carlhian

Rhododendron prinophyllum var. album
Picture by S & J Perkins
Rhododendron prinophyllum var. album in Salem, NH

Rhododendron prinophyllum

This deciduous azalea is in Subsection Pentanthera and is known by a number of common names: Roseshell Rhododendron, Mayflower Azalea, and Rosy Pinxterbloom.

Its specific epithet means, "with leaves like prinos" (prinos, from the Greek meaning oak, or winterberry (Prinos verticillata, now Ilex verticillata)).

The earliest reference I could find is a Cherokee Indian legend, ancient before the first Europeans reached our shores. After that, R. prinophyllum was mentioned as a variety of Azalea nudiflora in 1787 by Wangenheim, who found it in New York State. The species was likely in cultivation in Europe in the early 19th century, perhaps introduced by Peter Collinson for whom the American John Bartram collected. Several different specific names were given to this plant (nudiflorum, canescens and roseum), reflecting the immense uncertainty about the taxonomy of American azalea species and the proper priority of the nomenclature.

R. prinophyllum is native to open woods from southwestern Quebec to the mountains of Virginia, west to Missouri and northern Indiana; in the East it is found in Massachusetts, Vermont, Pennsylvania, and New York. The purest forms, the least contaminated by hybridization, are found in the Blue Ridge Mountains of Virginia. It is hardy to Zone 3, -25°F or lower; regularly to -40°F in Bellows Falls and Saxon River, Vermont.

R. prinophyllum is a shrub 2-8 feet rarely to 15 feet high, not usually stoloniferous. The leaves are bluish green and 3-7 cm long. The new growth and floral and winter buds are densely pubescent (fuzzy) and both surfaces of the true leaves somewhat hairy as well. The leaves are deciduous and elliptic in shape. The inflorescence has 5-9 flowers, opening in May along with the leaves. The flowers, which may be pink, purplish pink or rarely white, are strongly and delightfully clove-scented.

R. prinophyllum has been used for hybridizing where both extreme hardiness and fragrance are desired. The Abbott Hybrids, developed by Frank Abbott of Vermont and by Weston Nurseries, include: 'Frank Abbott' (R. prinophyllum x a red R. mollis selection); 'Jane Abbott', 'Peach Abbott', both mildew resistant with good fall color, 'Margaret Abbott' (R. prinophyllum x R. calendulaceum). The Northern Lights Series, developed by Albert G. Johnson in the late 1930's and Harold Pellett of the University of Minnesota starting in 1957, are a series of different color R. prinophyllum hybrids, hardy (some to -45°F) and most fragrant.

'Marie Hoffman' is a selected clear pink clone selected by Lud Hoffman; it is perhaps a tetraploid.

Elizabeth Carlhian, Concord, MA

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