Clethra alnifolia

Summersweet, Sweet Pepperbush




  • native along the entire eastern United States
  • most commonly founded in moist woodlands, especially near water
  • zone 4

Habit and Form

  • an upright deciduous shrub
  • 5' to 8' tall and 4' to 6' wide
  • multistemmed and suckering; can form colonies
  • sometimes with little foliage at the base of plants in shady locations
  • dense foliage in exposed locations
  • rounded to oval shape

Summer Foliage

  • alternate, deciduous leaves
  • 1.5" to 4" long and 1" to 2" wide
  • obovate shape with acute to accuminate tip
  • serrate leaf margins
  • green to dark green color
  • late to leaf out in spring

Autumn Foliage

  • yellow-green to golden brown
  • can be showy at times


  • numerous, small white flowers held in racemes.
  • racemes are 3" to 5" long and 0.75" wide
  • nicely fragrant
  • blooms in July and August
  • blooms on current seasons growth
  • showy


  • small capsules
  • turn brown in fall and persist for a year or two


  • brown on newer stems
  • gray brown on older stems


  • prefers moist, acidic soil with organic matter
  • transplant from container or B&B
  • may be slow to establish and some twig tip dieback may occur during the first winter.
  • relatively easy to grow
  • full sun to partial shade
  • avoid hot, dry sites

Landscape Use

  • screen
  • specimen perhaps
  • in groupings
  • shrub border
  • colonizing nature can be useful
  • highly useful for late summer fragrant flowers
  • site the plant so fragrance can be appreciated
  • tolerant of ocean-side plantings
  • naturalistic/native landscapes


  • relatively pest free except for spider mites
  • spider mites can be severe on plants in hot, dry locations

ID Features

  • fragrant spires of white flowers in mid to late summer
  • persistent fruit capsules
  • obovate, alternate, deciduous leaves with serrations
  • suckering, colonial type growth


  • by seed
  • easily rooted by summer cuttings
  • division of suckers


'Anne Bidwell' - Produces flowers that are larger than the species, also perhaps later. More compact, to 6' tall.

'Creels Calico' - The foliage of this selection is marked with variable creamy white variegation. The flowers are white, and the plant will probably mature at 4' tall. It's a rather interesting form.

'Hummingbird' - Perhaps the most popular commercial selection. Selected by Callaway Gardens for its compact growth, heavy flowering and shiny foliage. The plant matures at 3'-4' tall and has good fall color. Reports indicate good performance across a wide geographical range.

'Paniculata' - Purported to have large panicles of flowers, but the plant may be misnamed and not reliable in this floral performance.

'Pink Spires' - Buds are rose-colored and open to light pink. Flowers do not fade, and the plant grows to 8' tall.

'Rosea' - Pink flower buds open pink, but then fade to nearly white. An older cultivar.

'Ruby Spice' - The darkest pink selection. Red buds open to pink and do not fade. Dark green, glossy foliage. Selected by Andy Brand at Broken Arrow Nursery in Hamden, CT. This award-winning plant has been embraced by the nursery industry and is very common.

'September Beauty' - A new form that is reported to flower up to two weeks later than the species. Growth is more compact and the foliage is a good green.

© Copyright Mark H. Brand, 1997-2015.

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Citation and Acknowledgements: University of Connecticut Plant Database,, Mark H. Brand, Department of Plant Science and Landscape Architecture, Storrs, CT 06269-4067 USA.