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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: 8 US states
Climate fit: broad (77/100)
Structure
Pollinator
Border
Light
Full sun / Part shade
Water
Moderate water
Mature size
5-10 ft tall · 5 ft 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 8 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.
Black chokeberry (Aronia melanocarpa) showing clusters of shiny black berries against dark green foliage.
Aronia melanocarpa
Black chokeberry
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.
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Full sun / Part shade
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Climate: broad
Border
Pollinator
Structure
Edible
Carolina allspice (Calycanthus floridus) growing as an open, multi-stemmed deciduous shrub in its native Appalachian woodland, showing the upright-arching branching habit.
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
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Climate: broad
Pollinator
Structure
Border
Common ninebark (Physocarpus opulifolius) whole multi-stemmed shrub in green-season leaf, showing the arching habit and 3-lobed maple-like foliage.
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
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Climate: broad
Structure
Border
Pollinator
A mature oakleaf hydrangea (Hydrangea quercifolia) in flower - a broad, mounded multi-stemmed shrub studded with upright white panicles above coarse, deeply lobed oak-shaped leaves.
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 to 8 feet tall and 4 to 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
Zones 5a-9b
Climate: moderate
Focal point
Structure
Border
Pollinator
Arching stems of a possumhaw viburnum in autumn carrying four dense clusters of berries, each cluster holding rose-pink and slate-blue fruit together on red stalks. The leaves around them are glossy and turning from green to bronze-red, and the ground behind is bare mulch and gravel.
Viburnum nudum
Possumhaw viburnum
Two things to settle before anything else. First, the name: this catalog already carries a plant called Possumhaw, and it is a holly, Ilex decidua. They are unrelated, they want different ground, and only one of them is this shrub. Missouri Botanical Garden files this species under smooth witherod and mentions possumhaw viburnum second, which is the safer name to buy under. Second, the ground: this is the wet-soil viburnum. MBG rates it medium to wet water, lists wet soil as its one tolerance and rain garden among its two suggested uses, and the Lady Bird Johnson Wildflower Center puts it in savannas, low wet woods and bogs on wet, mucky, acid soils. That is the axis that separates it from its relatives here. Mapleleaf viburnum is the dry-shade suckering understorey shrub, nannyberry is the tall small tree of upland edges, and possumhaw viburnum is the one you plant where water sits. What you get for the wet feet is the best fruit display in the group and one of the best of any native shrub. The ovoid berries do not simply ripen, they run a colour sequence - light pink, then deep pink, then blue, then purplish black - and because a cluster ripens unevenly, deep pink and blue-purple berries commonly sit in the same cyme in late summer against glossy dark green leaves that follow with maroon to red-purple fall colour. The catch is that the display depends on pollination. MBG says outright to plant shrubs in groups rather than as single specimens for best cross-pollination and subsequent fruit display, so a lone plant is the one way to get all of the shrub and none of the reason for it.
Shrub
Full sun / Part sun / Part shade
Consistent moisture
Zones 5a-9b
Climate: broad
Structure
Pollinator
Border
Virginia sweetspire (Itea virginica) rounded mounded shrub in summer leaf, showing the dense suckering whole-plant habit.
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

Educator packet

Plant packet
Summersweet (sweet pepperbush) educator packet
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.
Scientific name
Clethra alnifolia
Plant type
shrub
Hardiness
3a-9b
Light
full-sun, part-shade
Moisture
moderate
Spacing
60 inches
Classroom prompts
- Which plant traits are observations, and which are care recommendations?
- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?
- Which source-backed facts would you cite in a lesson handout?
Use the Sources & citations section below for page citation styles and the field-level source list.

Sources & citations

Cite this page
For lesson plans, articles, or research that uses this page. Use the source cards below to explore the references that informed this record.
Plotwright. (2026, May 17). Summersweet (sweet pepperbush) (Clethra alnifolia). Retrieved 2026, August 20, from https://plotwright.com/plants/clethra-alnifolia
Sources used for this record
This record is compiled from the sources below.
NC State Extension Gardener Plant Toolbox
University extension service
USDA PLANTS Database
Government data source
Lady Bird Johnson Wildflower Center Native Plant Database
Botanical research database
Plants of the World Online (POWO)
Botanical research database
Wikimedia Commons
Photo · CC BY-SA 3.0