Plant Profiles: HORT 2241 Landscape Plants I

Botanical Name: Clethra alnifolia

Common Name: summersweet clethra, sweet pepperbush

Family Name: Clethraceae – summersweet or white alder family

General Description: Clethra alnifolia is native in the Gulf and Atlantic coastal plains primarily in acidic, wet, boggy habitats. In the landscape they are considered to be tolerant of a wide range of sun, shade, pH and moisture conditions. However, they perform best in the Chicago area in a well-mulched, moisture retentive soil, in a part shade condition where they are not exposed to the full afternoon sun. Clethra alnifolia is a lovely, four-season flowering shrub useful in mixed borders. The summer blooming flowers attract butterflies, bees and hummingbirds. There are several useful cultivar introductions mostly selected for flower qualities and plant size.

Zone: 4-9

Resources Consulted: Dirr, Michael A. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Champaign: Stipes, 2009. Print.

"The PLANTS Database." USDA, NRCS. National Plant Data Team, Greensboro, NC 27401-4901 USA, 2014. Web. 23 Mar. 2014.

Creator: Julia Fitzpatrick-Cooper, Professor, College of DuPage

Creation Date: 2014

Keywords/Tags: Clethra alnifolia, summersweet, clethra, sweet pepperbush, deciduous, shrub, flowering shrub, summer flowering shrub

Whole plant/Habit:  Description: Summersweet clethra is a twiggy, dense, upright oval flowering shrub. Under moist conditions it can sucker forming a small colony.  Image Source: Karren Wcisel, TreeTopics.com  Image Date: June 6, 2012  Image File Name: summersweet_4327.png

Flower:  Description: The flowers are the most attractive feature of summersweet clethra. Flowering mid- summer after most other woody shrubs have bloomed, they attract bees, butterflies and hummingbirds. The highly fragrant white (sometimes slightly pink depending on cultivar) flowers are borne on upright 4-6 inch racemes. They bloom bottom to top contributing to a long lasting flowering period of 4-6 weeks.  Image Source: Karren Wcisel, TreeTopics.com  Image Date: July 29, 2012  Image File Name: summersweet_2803.png

Fruit:  Description: The flowers give way to racemes of dried 3-valved capsules that persist through winter and provide a reliable identification feature. The seeds attract a variety of birds.  Image Source: Karren Wcisel, TreeTopics.com  Image Date: March 22, 2009  Image File Name: summersweet_0471.png

Leaf:  Description: The leaves are alternate on the twigs, simple and finely toothed (often entire near the base). They are medium to dark green in color and 1.5-4 inches in length and about half as wide. It is important to remember that the leaves are slow to emerge in spring. It is not dead!  Image Source: Karren Wcisel, TreeTopics.com  Image Date: July 29, 2012  Image File Name: summersweet_2802.png

Leaf:  Description: The leaves hold green until late October then change to light yellow, deepening to golden yellow with a hint of brown, before falling in mid- November.  Image Source: Karren Wcisel, TreeTopics.com  Image Date: October 27, 2012  Image File Name: summersweet_7470.png

Special ID feature(s):  Description: Everything about this plant is late! It leafs out late, flowers late, turns fall color late and holds its fruit late into the following year’s growth cycle. The persistent fruits are a very useful identification feature and add to the winter interest of this plant.  Image Source: Karren Wcisel, TreeTopics.com  Image Date: May 14, 2013  Image File Name: summersweet_4642.png