Clethra alnifolia
Overview
Uses: Rain gardens, pollinator gardens, woodland edges, shade gardens, and wet spots.
Benefits: The straight native species of summersweet, with upright spikes of very fragrant white flowers in mid to late summer, when few shrubs bloom. A top pollinator plant that thrives in moist soil and shade, with golden yellow fall color. Spreads slowly by suckers to form a thicket.
USDA Hardiness Zones: 4–9
Sun: Full Sun to Shade
Life Cycle: Deciduous Shrub
Growth Habit: Upright, Rounded — slowly suckering.
Bloom Color: White (very fragrant)
Foliage Color: Green, turning Golden Yellow in fall
Mature Height: 5–8 feet
Mature Width: 4–6 feet
Bloom Season: Mid to late summer
Growth Rate: Moderate
Summary
A native shrub that saves its sweetest moment for the heat of late summer.
Most flowering shrubs are finished by July. Summersweet waits. In mid to late summer it sends up upright spikes of small white flowers at the tips of the branches, and their spicy-sweet fragrance carries across a yard on warm, still evenings. The display lasts for several weeks, filling the gap between the early summer bloomers and the fall garden.
This is the straight species, native to the eastern United States from New England down the Atlantic and Gulf coasts. In the wild it grows along swamp edges, stream banks, and damp woods, which is why it settles so easily into soggy ground and shade that hold back most flowering shrubs. It forms an upright, rounded shrub five to eight feet tall and slowly widens by suckers into a loose colony.
The flowers are a magnet for bees and butterflies at a time of year when nectar can be scarce. In fall the leaves turn yellow to golden, and the small seed capsules hang on along the stems through winter.
Care
Summersweet Care
Summersweet grows in anything from full sun to full shade. More sun brings heavier flowering; in deep shade the plant stays a little looser and blooms more lightly, but still performs.
It prefers moist, acidic soil rich in organic matter and tolerates wet, poorly drained ground and periods of standing water. Hot, dry, or alkaline sites are the conditions it handles least well, so give it a spot that does not bake.
Water deeply once or twice a week through the first growing season while roots establish. After that, keep soil evenly moist, especially in sunny spots and during summer dry spells. A two-to-three-inch layer of mulch helps hold moisture and keep roots cool.
Feeding needs are light. One application of a slow release fertilizer in early spring is plenty, and plants in rich soil often need none.
Summersweet flowers on new growth, so prune in late winter or early spring before leaves emerge. Remove a few of the oldest stems at the base every few years to keep the plant vigorous. It is one of the last shrubs to leaf out in spring, so bare branches into May are normal. Pull or cut suckers if you want to hold it to a single clump, or let them fill in a naturalized planting.
Size
What Size is the Summersweet for Sale Online?
Our Summersweet ships in a greenhouse-grade grow pot and is appropriately sized for its container at the time of shipment. Plants ship dormant or near dormant in the off-season, so they may arrive with few or no leaves. If you have specific sizing or planting questions, please contact us.
How Large Does Summersweet Grow?
Expect about 5 to 8 feet tall and 4 to 6 feet wide at maturity, in an upright, rounded shape. Left alone, it slowly spreads wider through suckers. Space plants about 4 to 5 feet apart for an informal hedge or mass planting.
Additional Information
What are some common names for this plant?
- Summersweet
- Sweet pepperbush
- Coastal sweet pepperbush
Is summersweet a native plant?
Yes. Clethra alnifolia is native to eastern North America, and this is the straight species rather than a named cultivar. It belongs naturally in rain gardens, woodland edges, and wildlife plantings. Browse more Native Plants of North America.
Do deer eat summersweet?
Deer usually leave it alone, and it is widely rated as deer resistant. Hungry deer will browse almost anything in a hard winter, but summersweet is a dependable choice where browsing is a problem. See more Deer-Resistant Shrubs and Evergreens.
Will it grow in wet soil or shade?
Yes, and that is where it earns its place. Summersweet handles low spots that stay damp, ground near downspouts, and the shade of larger trees, conditions where many flowering shrubs fail. It is just as happy in an ordinary garden bed with steady moisture.
How is the straight species different from compact summersweet cultivars?
Compact cultivars such as Sixteen Candles stay closer to three or four feet and are bred for a tidier footprint. The straight species grows taller and spreads more freely, which suits it to naturalized plantings, woodland edges, and larger wet areas. For more options, browse our Shrubs & Bushes.
