Rhododendron catawbiense
Catawba Rhododendron
Mature Size, Growth, Longevity
Average mature size 6-10' tall and 5-8' wide, rarely to 15-20' tall. National champion is 25' tall by 15' wide. Usually taller than wide, but does form a rounded shape with large, dense foliage to the ground. Slow growth rate. Moderately short-lived, reaching an age of 50-100 years under ideal conditions.
Native Range
Kentucky Native — Native to the Alleghenies, West Virginia, southwest to Georgia and Alabama. Also native to a few counties in east-central and southeast Kentucky. Introduced 1809.
Flower and Fruit Details
Flower buds are large and pointed, on the species yellowish-green opening to lilac-purple or sometimes purplish-rose, with green/yellow-brown markings on the inside of the corolla. Each flower 1.5-2.5" wide, grouped in 5-6" wide racemes, late May. Fruit in dehiscent capsules, 5-valved.
Leaf and Bark Features
Evergreen: Leaves alternately arranged, simple, broadleaf evergreen, elliptic to oblong, 3-6" long and 1-2" wide. Dark green above, light green beneath. Glabrous and leathery texture. Petiole 0.5-1.25" long. On new stems, bark is yellowish-green. With age bark changes to brown, glabrous.
Culture and Care
Needs moist, acid, organic soil, pH 4.5-6.0. Must have good drainage, and needs light shade. Is sensitive to salinity, high pH, and winter injury. Mulch will be helpful. Zones 4-8. Avoid drought and compaction. Susceptible to botryosphaeria canker, crown rot, dieback, leaf spots, leaf scorch, powdery mildew, rust, shoot blight, shoestring root rot, wilt, aphid, lace bug.
Strengths, Weaknesses, Other Facts
Excellent lustrous dark green foliage through winter. 4-season interest: Spring, Summer, Fall, Winter. One of the hardiest and best known of all the broadleaf evergreen rhododendrons, but still requires good drainage.
Suggested Uses
Beautiful when used in groupings or mass plantings. Also used as a foundation plant or a specimen plant, or for shady sites. Planted as much for the large evergreen foliage as it is for the flower display.
Taxa and Plants of this Species at BCA
The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.
Rhododendron catawbiense 'Album' // White Catawba Rhododendron
Shrub. Flower buds flushed lilac, opening to pure white flowers with greenish-yellow spotting, held in compact, rounded trusses. Grows to 6' tall with excellent lustrous dark green foliage. Great hardiness down to -25°F. Good plant vigor.
-- not currently in our collection --Rhododendron catawbiense 'Nova Zembla' // Nova Zembla Catawba Rhododendron
Shrub. A dense-growing, small evergreen shrub, with showy red flowers, often used for foundation plantings, as an accent plant, in hedges, mass plantings, privacy screens, woodland gardens, or shade gardens. Lavender-red to pure red flowers. Grows to 5' tall and wide. One of the best selections for the Midwest, cold tolerant to -25°F and also quite heat resistant, so also does well in the South.
Bed 40Rhododendron catawbiense 'Roseum Elegans' // Roseum Elegans Catawba Rhododendron
Shrub. A medium-sized, 6-8' tall & wide, vigorous grower with reliable flowering with large trusses of lavender-pink (rosy purple or rose-lilac) blooms. Withstands temperature extremes without injury, cold tolerant to -25°F and has excellent heat tolerance. Protection from winter wind is helpful to prevent winter desiccation. There is more than one form sold under this name. Makes a great plant for foundation plantings, hedges, mass plantings, woodland gardens, shade gardens or as an accent plant or specimen plant in the landscape.
Bed 38Rhododendron catawbiense 'Roseum Pink' // Roseum Pink Catawba Rhododendron
Shrub. Strong grower making a broad, full plant with clear pale pink flowers. Zone 4 hardy to -25°F. Dark green foliage. Gets 5' tall and 6' wide. Excellent as an accent plant, specimen plant, native garden plant, or used in a mass planting, in shade gardens, or in a naturalized planting. The cultivar name, 'Roseum Pink', is sometimes used interchangeably with 'English Roseum'.
Bed 42