‘Pink Spire’ clethra

‘Hummingbird’ clethra

Summersweet clethra (Clethra alnifolia), aka sweet pepperbush, is a deciduous summer blooming shrub that ranges from coastal Maine to Florida (USDA hardiness zones 4-8). This delightful shrub grows 3-6 feet, although some cultivars grow 8 feet or higher. Flower colors (depending on variety) range from white, pink, and rose pink.

The sweetly fragrant flower clusters ( 4- 6 inches long racemes) are visited by multitudinous bees, a few butterflies, as well as by gardeners. When in bloom, the area is “a buzz” with bee activity lasting approximately 4 weeks in July and August.

Flowers give way to dark brown seed capsules that often persist through winter. The glossy dark green leaves (to 4 inches long) develop foliage shades of yellow to golden brown, which may linger for several weeks in autumn.

Summersweet is easy to grow in either full to partial sunlight and in average soil that is well- drained and mildly pH acidic. This native shrub thrives in wet sites and is both heat and cold tolerant. It tolerates dry soils after a two year period of establishment, but grows best and produces the greatest number of flowers when watered regularly. Avoid the hot afternoon sun in southern climes. Once a year feeding in late winter with a slow-release fertilizer such as Osmocote™ or Nutrikote™ is sufficient.

Summersweet is mostly disease- and pest-free. Pruning, if needed, should be done in late winter before spring growth begins. Little pruning is generally needed, unless it has outgrown its space. Every 5-6 years consider cutting shrub(s) to the ground in late fall. This tough reliable  plant will bloom the following summer. Summersweet spreads by rhizomes and suckers; remove unwanted plants at any time.

Selected cultivars to try:

‘Hummingbird’ is a 3- 3 ½ foot tall compact form with deep green summer foliage

‘Rosea’ is a popular pink flowering form with pink flowers that fade to white.

‘Ruby Spice’ bears deep rose pink 3 ½ – 4 inch flowers; it grows into a 6 – 8 foot tall shrub.

‘Sixteen Candles’ bears larger 4 – 6 inch long flowers that stand upright and do not flop like most cultivars.