Vermont Garden Journal: Clethra

Jul 29, 2016

I like a shrub with a description that says it tolerates shade, clay soil, wet soil and erosion and still blooms. This shrub is called the pepperbush or summersweet. Its botanical name means “alder” in Greek since the leaves resemble those of the alder tree. We call it clethra.

Not only is clethra a tough, native shrub that grows 3 to 6 feet tall and wide, it's tolerant of wet soils and shade. It's unique in that it flowers now, when few other shrubs flower, and blooms in shade. The sweet smelling blooms are white or pink, depending on the variety, and flower from mid summer until fall. Butterflies and bees love this shrub so it's a good one for pollinator gardens. Because of its versatility, clethra can be planted in many spots in your yard. Plant it in part shade along the house as a foundation plant, in full sun in a hedgerow with other shrubs or along a stream or pond for erosion control.

Clethra is hardy to zone 4 and has a number of newer varieties. 'Hummingbird' and 'Sixteen Candles' are more compact growing selections reaching only 3 feet tall and wide. The flowers have a sweet, clove-like scent. 'Pink Spire' and 'Ruby Spire' have colorful flowers that also have a strong fragrance. Cinnamon clethra is only hardy to zone 5, but produces brilliant, golden fall foliage.

Clethra tolerates a range of soils, but needs constant moisture to grow best. After planting, mulch well and keep the shrub well watered the first year. Clethra blooms on new growth, so prune in spring to remove older branches and errant shoots. This will stimulate the production of new stems and more flowers in summer.

And now for this week's tip: Harvest veggies early and often. Pick beans, cucumbers, and zucchini while the fruits are small to stimulate more production and have more tender fruits. Harvest beans before they form seeds, cucumbers when they're 3 to 6 inches long and squash with the flowers still attached.

Next week on the Vermont Garden Journal, I'll be talking about new hydrangeas. Until then, I'll be seeing you in the garden.