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Summersweet (sweet pepperbush)

Summersweet (sweet pepperbush)

Clethra alnifolia
A native eastern North American deciduous shrub of swamps + damp thickets + sandy woods producing fragrant white-to-pink upright flower spikes in late summer when few other shrubs are blooming. Among the most fragrant native shrubs available; deer-resistant; tolerates wet feet + occasional flooding. Outstanding choice for rain gardens, shady borders, and low-maintenance native plantings.
Native: 9 US states
Climate fit: broad (78/100)
Structure
Pollinator
Border
Light
Full sun / Part shade
Water
Moderate water
Mature size
60-120" tall · 60" apart
Hardy in zones
3a-9b
brutally cold to frosty winters
AHS heat range
1-11
Plant range authored in AHS heat-zone terms.
Native in Illinois
No

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Native across 9 US states and Canadian provinces — a wide-ranging part of North America's plant communities.

Cold hardiness

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Well-suited
Zone 7a
Plotwright
0°F to 5°F
Well-suited
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
Well-suited today and still thriving in 2050.

Heat tolerance

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...

Similar plants

Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
Aronia melanocarpa
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A drought-and-flood-tolerant native shrub of eastern North America with brilliant three-season interest — spring white-pink flowers, glossy black antioxidant-rich late-summer berries, and brilliant wine-red fall foliage — plus an extraordinarily wide cold-hardiness range (USDA 3a-8b). The berries are astringent fresh but the basis of a small but growing commercial industry (juices, wines, jams, supplements) for their exceptionally high anthocyanin content. Spreads by suckers; site where colony formation is welcome.
Shrub
Full sun / Part shade
Moderate water
Zones 3a-8b
Climate: broad
Border
Pollinator
Structure
Edible
Calycanthus floridus
Carolina allspice (sweetshrub)
A native southeastern US deciduous shrub with deep-red strap-petaled fragrant flowers in late spring — the scent variously described as strawberry, banana, or wine, and reliably present only on cultivated cultivars with selected fragrance. Among the most distinctive native shrubs for woodland-edge and shaded mixed borders.
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Full sun / Part shade
Moderate water
Zones 4a-9b
Climate: broad
Pollinator
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Physocarpus opulifolius
Common ninebark
A native North American deciduous shrub with exfoliating bark (hence "ninebark"), white-to-pink spring flower clusters, papery red seedpods, and reliable fall color. Colored-foliage cultivars (Diabolo, Coppertina, Summer Wine) extend the design palette. Adaptable + drought-tolerant once established.
Shrub
Full sun / Part shade
Moderate water
Zones 2a-8b
Climate: broad
Structure
Border
Pollinator
Hydrangea quercifolia
Oakleaf hydrangea
A four-season native shrub of the southeastern United States, where NC State Extension notes it grows wild in moist woods and along stream banks. It is an upright, multi-stemmed deciduous shrub, slow-growing to roughly 4-8 feet tall and 4-10 feet wide, named for its large, oak-shaped, lobed dark-green leaves. Showy pyramidal 4-12 inch panicles of creamy-white flowers open from late spring into summer and fade to pink and then tan, while the bold foliage turns wine, orange, and mahogany in fall over peeling cinnamon bark. Easy and low-maintenance in organically rich, well-drained soil, it is grown as a specimen, in masses, or as an informal hedge.
Shrub
Full sun / Part shade
Moderate water
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Climate: moderate
Focal point
Structure
Border
Pollinator
Itea virginica
Virginia sweetspire
A native eastern North American deciduous shrub with fragrant pendant white flower spikes in late spring, brilliant red-purple fall color (often holding leaves into early winter), and excellent wet-soil tolerance. NC State documents it as deer-resistant + suckering-form. Outstanding rain garden + woodland-edge specimen.
Shrub
Full sun / Part shade
Consistent moisture
Zones 5a-9b
Climate: broad
Structure
Pollinator
Border
Viburnum dentatum
Arrowwood viburnum
A native eastern + central North American multi-stemmed deciduous shrub with dentate (toothed) foliage, white spring flower clusters, blue-black drupes, and reliable fall color. Especially valued for wildlife — among the most-cited native shrubs for fall-migration bird forage.
Shrub
Full sun / Part shade
Moderate water
Zones 2a-8b
Climate: broad
Structure
Pollinator
Border

Sources & citations

Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Summersweet (sweet pepperbush) (Clethra alnifolia). Retrieved 2026, June 24, from https://plotwright.com/plants/clethra-alnifolia
Sources for every fact
Every fact on this page traces to a source. 18 fields cited - 18 source-backed.
NC State Extension Gardener Plant Toolbox
University extension service
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
Growth stages
Lifecycle
Regional guidance
Success tips
Designer notes
Wikimedia Commons
Photo · CC BY-SA 3.0
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Image