Rhododendron carolinianum (Carolina Rhododendron)


Michael's Opinion

An excellent border plant and if grouped properly can create a beautiful focal point in most gardens. Protect from winter sun and strong winds. Soil must be acidic. Mulch after planting and supercharge before winter and protect from snow build up.

Botanical Information

FamilyEricaceae
GenusRhododendron
Speciescarolinianum
CategoryWoody
TypeShrub (evergreen)
OriginFound in south-western North Carolina, south-eastern Tennessee, north-eastern Georgia and north-western South Carolina. Was introduced into cultivation in 1815.
Pronunciation

Details

USDA Hardiness Zone 4-8
USDA Hardiness Ref.
Canada Hardiness Ref.
RHS Hardiness Ref.
Temperature (°C)-29 - (-34)
Temperature (°F)-20 - (-30)
Height10-12 m
Spread5-8 m
GrowthSlow
Flowering PeriodMay

Description and Growing Information

General DescriptionBroad leaved evergreen, slow growing dense globular shape; leaves aromatic if bruised. White to light rose coloured flowers.
ID CharacteristicLeaves are narrow 5-7 cm long and 1-4 cm wide, petiole is .5-1 cm long and when the leaf if bruised releases an aroma.
ShapeSmall, globe like form. Commonly loose and open in the wild
LandscapeOften used in borders or planted in groups or masses. Try to plant in mildly shaded areas and out of winter sun and windy areas.
PropagationGrowing from seed requires minimal effort. Cuttings are relatively difficult to root however, if treated with hormone and fungicide will give a reasonable percentage of success if done in late summer . Plant in shady area with acidic soil, avoid windy areas.
CultivationBe sure when planting to mulch an adequate area around the site. The rhododendrons require acidic soil to flourish.
PestsBotryosphaeria canker, crown rot, dieback, dampening off, Japanese beetle, giant hornet, azalea leaf tier, Asiatic garden beetle, lace bugs, rhododendron aphids, powdery mildew, rust, azalea stem borer, leaf scorch, shoestring root rot and shoot blight.
Bark/Stem DescriptionDeep to dark purplish red during summer months, becomes lighter over winter. Older wood is greyish brown.
Flower/Leaf Bud DescriptionYellowish flower buds are 2 -3 times the size of vegetative buds. Vegetative buds measure .5-1 cm.
Leaf DescriptionAlternate arrangement, simple, narrow 5 -7.5 cm long, 1-4 cm wide. Elliptical shape: dark green surface, scaly underside. The petiole is .5- 1cm long, aromatic and when bruised.
Flower Description4-10 flowered colour forms from pure white to light rose.7.5 cm in diameter. Blooms in mid-May to early June.
Fruit DescriptionDehiscent 5-valved capsule, recommended that flowers be removed after they have finished to avoid seed set. Fruit vary in size .5cm-1cm and are greenish red.
Colour DescriptionDark green in the summer, deep purple leaves in winter months. Bark is a lighter purple over winter months but becomes dark purplish red in the summer months.
Texture DescriptionMedium to coarse all year.

Photographs