Clethra alnifolia L.
Coastal pepperbush, Coastal sweet pepperbush, Coastal sweet pepper, Alderleaf pepperbush, Alderleaf clethra, Clethra, Summer sweet
Clethraceae (Sweet-Pepperbush Family)
Synonym(s): Clethra alnifolia var. tomentosa, Clethra tomentosa
USDA Symbol: clal3
Coastal sweet-pepper or summer sweet is a narrow, 6-12 ft., deciduous shrub, which often spreads into mounded clumps. A tall, many-branched, leafy shrub with spike-like, upright clusters of fragrant white flowers. The shrub has erect, multiple stems; exfoliating bark; and simple, oval, toothed leaves which turn dull yellow to orange in fall. The dense, narrow, cylindric flower spikes are often clustered together at branch ends. Fragrant flowers are white and are followed by brown capsules which persist through winter.
This shrub forms sizable patches and is remarkably free of any disease, insect, or physiological problems. Its dry fruiting capsules remain long after flowering and help identify this plant in winter. Mountain Pepperbush (C. acuminata) has more pointed leaves and is found in southern mountains.
From the Image Gallery
Plant CharacteristicsDuration: Perennial
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Venation: Pinnate
Leaf Margin: Serrate
Breeding System: Flowers Bisexual
Size Notes: Normally 3 to 6 ft, but can reach 12 ft.
Leaf: Green, turning pale gold in fall. New growth bronzy.
Autumn Foliage: yes
Flower: Flowers in 3 to 8 inch spikes
Size Class: 3-6 ft. , 6-12 ft.
Bloom InformationBloom Color: White , Pink
Bloom Time: Jul , Aug
Bloom Notes: Blooms on new growth
DistributionUSA: AL , CT , DE , FL , GA , LA , MA , MD , ME , MS , NC , NH , NJ , NY , PA , RI , SC , TN , TX , VA
Native Distribution: MS to FL, n. through eastern portions of the coastal states to s. ME; also locally in LA & TX
Native Habitat: Swamps; sea shores; stream banks; hillside bogs
Growing ConditionsWater Use: High
Light Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist , Wet
Soil pH: Acidic (pH<6.8)
CaCO3 Tolerance: Low
Drought Tolerance: Low
Soil Description: Many wet to moist, acid soils, including sands and clays.
Conditions Comments: Excellent for coastal gardens due to salt-spray tolerance.
BenefitUse Ornamental: Fragrant, showy summer flowers. Outstanding fall color.
Use Wildlife: Bees, butterflies, and hummingbirds use flowers. Many birds and mammals eat the fruit.
Conspicuous Flowers: yes
Fragrant Flowers: yes
Interesting Foliage: yes
Attracts: Birds , Butterflies , Hummingbirds
Value to Beneficial InsectsSpecial Value to Native Bees
Special Value to Bumble Bees
Special Value to Honey Bees
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
PropagationPropagation Material: Clump Division , Root Division , Seeds , Softwood Cuttings
Description: Propagate by seed or softwood cuttings, with or without hormone treatment, under mist. Sow seed on sand.
Seed Treatment: Tiny seeds require no pretreatment.
Commercially Avail: yes
Maintenance: This versatile, carefree shrub responds well to pruning.
Find Seed or Plants
View propagation protocol from Native Plants Network.
Mr. Smarty Plants says
Native shrub to replace non-native azaleas.
February 10, 2009
I want to replace my two dozen azaleas this spring (I think they're unattractive once the flowers fall off). I like the multiseason characteristics of weigela (midnight wine, W&R), but want to go na...
view the full question and answer
National Wetland Indicator Status
From the National Suppliers DirectoryAccording to the inventory provided by Associate Suppliers, this plant is available at the following locations:
Edge of the Woods Native Plant Nursery - Orefield, PA
LAMTREE FARM - Warrensville, NC
ArcheWild Native Nurseries - Quakertown, PA
Toadshade Wildflower Farm - Frenchtown, NJ
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Native Plant Center at Westchester Community College, The - Valhalla, NY
Delaware Nature Society - Hockessin, DE
United States Botanic Garden - Washington, DC
Crosby Arboretum - Picayune, MS
Georgia Native Plant Society - Atlanta, GA
Mt. Cuba Center - Hockessin, DE
BibliographyBibref 1620 - Gardening with Native Plants of the South (Reprint Edition) (2009) Wasowski, S. with A. Wasowski
Bibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.
Search More Titles in Bibliography
Research LiteratureReslit 1141 - Cytological analysis of a Clethra alnifolia 'Hokie Pink' x C-pringlei hybrid (2005) S. M. Reed
Reslit 1143 - Reproductive biology of Clethra alnifolia (2006) S. M. Reed
Reslit 1144 - Interspecific hybridization in Clethra (2002) S. M. Reed, Y. Joung and M. Roh
Reslit 1270 - Host status of woody ornamental plants native to Southeastern USA to three Meloidogyne species (2005) J. Sharma and J. R. Rich
Reslit 1980 - Evaluation of self-compatibility in Clethra alnifolia (2006) S. M. Reed
Reslit 2185 - Effects of canopy opening on recruitment in Clethra alnifolia L (Clethraceae) populations in central New Jersey wetland forests (1996) R. A. Jordan and J. M. Hartman
Reslit 2304 - The Essential Oil of Clethra alnifolia L Flowers (1985) J. C. Hemingson
Reslit 2350 - Safe sites and the regeneration of Clethra alnifolia L.(Clethraceae) in wetland forests of central New Jersey (1995) R. A. Jordan and J. M. Hartman
Reslit 2416 - The Floral Morphology of Clethra alnifolia with some Notes on C. acuminata and C. arborea (1952) L. G. Kavaljian
This information was provided by the Florida WIldflower Foundation.
Search More Titles in Research Literature
From the ArchiveWildflower Newsletter 1998 VOL. 15, NO.5 - Native Shrubs Providing Landscape Heritage and Habitat, Executive Director\'s Re...
Additional resourcesUSDA: Find Clethra alnifolia in USDA Plants
FNA: Find Clethra alnifolia in the Flora of North America (if available)
Google: Search Google for Clethra alnifolia
MetadataRecord Modified: 2015-09-30
Research By: TWC Staff