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...
Where this plant fits
Suitable across 45 ecoregions - 41 climate-resilient through 2070 · 1 suited today · 3 newly possible by 2070. Best matches first.
Similar plants
Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
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.
Lady Bird Johnson Wildflower Center Native Plant Database
Botanical research database





