Plant Profile: Common Elderberry

 Sambucus canadensis or Sambucus nigra subsp. canadensis

Common elderberry growing on the edge of a cattail marsh. The largest inflorescence (center left) is at least 10 inches wide.

Late June into July is prime time to spot common elderberry, also called black elderberry and American elderberry. These large, multi-stemmed shrubs produce small, white flowers in flat clusters that reach 10 inches wide -- the size of dinner plates. They're hard to miss.

Most likely, you'll find the shrubs along the edges of woodlands, wetlands, ponds, ditches and other moist to wet, open habitats. They grow to about 12 feet tall with slightly arching stems that are greenish when young and gray-brown when older. The bark of older stems is rough or warty from the presence of large, raised lenticels, areas of porous bark that allow the exchange of oxygen and carbon dioxide with the environment.

Older stems of common elderberry have prominent lenticels. Leaf scars are
left when last year's leaves fall of the stem.

Starting in late June, the shrubs produce flat or slightly domed inflorescences (clusters) of white florets at the ends of their stems. The florets are tiny -- no more than a quarter of an inch (about 5 mm) wide with five white petals, five stamens and a stubby, central pistil. The flowers are said to be fragrant, with a sweet, lemony, slightly musky odor. Some describe it as pleasant, others not so much. 

Common elderberry begins flowering in early summer. producing flat or slightly domed inflorescences of tiny florets. Each floret has five white petals, five radiating stamens and a short pistil.

The flowers attract a variety of pollinators. According to the Minnesota Pollination Guide, common elderberry is visited mostly by generalists, insects that seek pollen or nectar from many species of flowering plants. Illinois Wildflowers lists honeybees, carpenter bees, bee flies and scarab beetles among the plant's many pollinators.

The MN Pollination Guide also lists two moths as specialist pollinators: the elderberry shoot borer moth, Achatodes zeae, and the rusty tussock moth, Orygia antiqua. According to other sources, though, neither of them pollinates this plant. In fact, both are considered pests. Elderberry shoot moth larvae, also called spindle worms, bore into and feed inside elderberry stems, causing them to wilt (1). The larvae of rusty tussock moths feed on the leaves of many kinds of plants, evidently including elderberry (2). Many other insects also feed on various parts of the plant (3). 

Once pollinated, the flowers develop into small, deep purple fruits called drupes. Many birds eat the fruits, including robins, cardinals, blue jays, catbirds, song sparrows and wild turkeys (3). People, too, have long harvested the ripe fruits to make wine, pies, jelly and syrup. This takes some care, though, because elderberry stems, leaves, bark and unripe fruits contain potentially harmful levels of cyanogenic glycosides, which can release cyanide. Best advice is to avoid eating stems, leaves and unripe fruits and to cook ripe fruits before eating or baking with them (4, 5). 

Left: Common elderberry fruits turn from green to dark purple when they're ripe. Right: This single leaf is divided into seven leaflets. The lowermost leaflets are deeply lobed. They're almost divided into extra leaflets.

When it's not flowering or fruiting, common elderberry is identified by its opposite, pinnately divided leaves and its arching, warty stems. This is a pioneer species -- one that is among the first to inhabit an open or disturbed site  -- so it thrives in full sun. It spreads not only by seeds but also by rhizomes to form patches or thickets. This habit makes the shrub valuable for stablizing streambanks, wetland edges and other sites being reclaimed or restored (4, 6, 7). 

Common elderberry is similar to red elderberry (Sambucus racemosa), another native shrub, but the two are easily told apart by their flowering season, the shapes of their flower clusters, the color of their fruit and their habitats. Red elderberry blooms in early spring with pyramidal clusters of flowers that produce red fruits. In contrast, common elderberry blooms in early summer with more or less flat flower clusters that produce dark purple fruits. 

Red elderberry fruits, like the flowers, are in a pyramidal cluster.

Their habitats also differ. Red elderberry, the more shade-tolerant of the two, often grows in woodland understories. In contrast, common elderberry typically grows in open sites with more sun, although it's often spotted along woodland edges. 

In winter, elderberries can be identified by their clumps of arching stems, large lenticels, large opposite buds, and broadly triangular, V-shaped or U-shaped leaf scars. Common and red elderberry can be told apart by the color of the pith, the soft tissue in the center of the stem. Common elderberry has a white pith, whereas red elderberry has a yellow-brown pith.

Left: The white pith of common elderberry. Right: The yellow-brown pith of red elderberry. 

Several dogwood (Cornus) and Viburnum shrubs also resemble common elderberry in having flat inflorescences of small, white florets. Even their widest inflorescences are not as wide as those of common elderberry, however, and their leaves are smaller and simple, not divided. They bloom in spring instead of early summer. 

Highbush cranberry, Viburnum opulus var. americanum, has flat clusters of white
florets, but the outer florets are much larger than the inner florets. As seen in the
 upper right, the leaves are three-lobed but not divided.

Nannyberry, Viburnum lentago, has simple leaves. Typically the inflorescence
is 2-3 inches wide. Photo (c) 2005 Peter M. Dziuk, Minnesota Wildflowers. 

The inflorescences of pagoda dogwood, Cornus alternifolia, are 1-3 inches wide.
Florets have four petals, not five.  Leaves are simple with arcing veins.
Photo (c) 2014 Peter M. Dziuk, Minnesota Wildflowers.

Cited references

1. Integrated Pest Management, University of Missouri: Spindleworms in Elderberry Shoots

2. iNaturalist: Rusty tussock moth.

3. Illinois Wildflowers: Common Elderberry (Sambucus nigra canadensis)

4. Three Rivers Park District: Species Spotlight - Elderberries. 

5. Michael K Appenteng, Ritter Krueger, Mitch C Johnson and others. Cyanogenic Glycoside Analysis in American Elderberry. Molecules, Vol. 4, No. 5. March 4, 2021.

6. Rose C. Wetlzel, Adrienne R. Hobbins, and Matthew J. Wilson. Survival and Growth of Wetland Species as Live Stakes with Lessons for Effective Management Practices. Natural Areas Journal, Vol. 43, No. 4. 2023. Note: Abstract only.

7. Hannah E. Ormshaw and Toim P. Duval. Response of thicket swamp species to soil moisture levels: Implications for restoration. Ecological Engineering, Vol. 153. 2020. Note: Abstract and Introduction only.

Additional references

Minnesota Wildflowers

Three Rivers Park District

BWSR Featured Plant

Minnesota DNR - Minnesota Pollination Guide

Integrated Pest Management, University of Missouri: Spindleworms in Elderberry Shoots