Clethra: Deer Resistant, Fragrant, and Pollinator Catnip

One summer day working at a client’s garden doing routine maintenance, I caught a whiff of wonderful fragrance on the breeze. After searching for the source, I came upon a mid-sized shrub full of narrow, spike-like creamy white flowers with an extremely sweet fragrance. Alive with insects darting in and out, the shrub swayed in a slight breeze wafting fragrance. That was my first experience seeing a Summersweet, Clethra alnifolia, at its peak of bloom and fragrance, and it left a lasting impression with me. Clethra is one of the best shrubs for mid to late summer color and fragrance. 

Spikes of fragrant flowers top the branches of this ‘Ruby Spice’ Clethra. Purple clouds of Thalictrum, Meadow Rue, tower over

Clethra has lots of other reasons to grow besides the knock-out fragrance and the beautiful abundant flowers. The yellow fall color is a standout and the shrubs shine with a clear yellow light, even on a  cloudy day.

In fall, the yellow foliage stands out

Glossy dark green leaves with exfoliating brown bark makes this a complete multi-seasonal interest package. The fragrant flowers are followed by brown capsules, which attract small mammals and birds. A tall (6-10′), many branched, deciduous shrub, clethra often spreads into mounded clumps, spreading by suckers that pop up nearby.

Over time, the shrub spreads to form a colony

There are dwarf forms, notably Sugartina from Proven Winners and these look good planted in a group.

‘Sugartina Crystalina’ Clethra forms a small mound about 30″ tall and wide; photo from Proven Winners

Culture

Easily grown in average, medium to wet soils in full sun to part shade, Clethra is a valuable plant for wet situations where many other shrubs would die. it tolerates clay soils and full shade as well. Sending out suckers or runners, you can easily remove these unless you want it to naturalize and spread in a large area.

The flower spikes make great cuts; photo from Proven Winners

Prune if needed in late winter to shape the shrub, but many times, I leave it alone. Since the shrub blooms on new growth, pruning can be done without any harm to the future flowering. Sometimes after a harsh winter, pruning is a good way to rejuvenate the shrub, removing any old or weakened branches. Clethra tolerates occasional flooding, actually thriving in wet soil, which makes this a perfect rain garden plant.

Clethra flowers can be creamy white or pink, depending on the cultivar

Native from Maine to Florida and west to Texas, it is found in the wild in mashes, stream banks, and along seashores. Flowering in mid to late summer, when most shrubs are done, the flowers are like magnets for butterflies, hummingbirds, and bumblebees, honey bees, and other native bees – a huge draw! Even in shade, Clethra will flower profusely, so it is a great native for woodland gardens. I like to group the shrubs in borders for dramatic impact. 

After I designed a healing labyrinth for a client, I surrounded it with Clethras which light up the entire area in the fall with their yellow color. Rarely bothered by deer and not troubled with disease or insects, this is an extremely versatile native shrub. Noted plantsman Michael Dirr says of this plant, “This is one of my favorite shrubs and the more I work with it, the greater my appreciation for its user-friendly nature”. 

‘Ruby Spice’ is a taller variety with soft pink flower spikes

 

11 Replies to “Clethra: Deer Resistant, Fragrant, and Pollinator Catnip”

  1. This is the “go to” shrub for pollinators. My honey bees love it. Beach Plums are a favorite too!

  2. Thank you for this post. This plant has been reliable & trouble free n my garden for 6 yrs. It’s planted in partial shade beside the pond along with Karl Foerster grass & Calacarpa . I don’t know of anyone else in this area (or my garden club) that has it.

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