Dogwood Days

This spring, take time to discover West Virginia’s many species of dogwood—and their importance to their ecosystems.

This story was originally published in the April 2017 issue of Wonderful West Virginia.

written by Mikenna Pierotti

It’s the last few days of April, and with them the last of the early morning frosts have given way to warm rains. Life is returning. Even deep in the mountain forests, places dark and cold enough to hang onto their snow are
submitting to the sun. Here, you might run into a shock of white at the edge of a wooded path and think it’s nothing more than a stray patch of ice. But look closer.

Against a backdrop of dark pines and new green leaves, the flowering dogwood, Cornus florida, native to West Virginia, is one of spring’s most romantic harbingers—especially toward spring’s end, when those lovely white flowers catch the breeze and rain down like snow in May.

But flowering dogwood is just one type you might find on a spring walk. There are several species of dogwood native to West Virginia—from the high-elevation-loving red-osier dogwood to the rare roundleaf dogwood—and each is an important part of the ecosystem it inhabits, providing food and shelter for birds, animals, and insects.

Common and Uncommon Beauties

If you’ve been on a hike in a West Virginia forest, chances are you’ve slipped past a dogwood or two. Matt Kasson, assistant professor of plant pathology at West Virginia University, says they are some of the easiest to distinguish, both from other plants in the forest and from each other. “Dogwoods are generally short in stature and can generally be distinguished by their blossoms, berries, and distinctive bark,” he says.

To identify a dogwood leaf, it can be helpful to remember three things, says Jim Vanderhorst, vegetation ecologist with the West Virginia Division of Natural Resources’ Natural Heritage Program. One, the leaves have what are called “entire margins,” meaning the edges have no teeth, and their shape is “simple,” lacking lobes like you would see on a maple or oak leaf. The leaves also have a unique pattern of veins, with two terminal veins that curve forward and meet at the point of each leaf. Once you can pick out those three attributes, you’ll be spotting dogwood everywhere.

Cornus alternifolia, or alternate-leaved dogwood, is found in at least 35 West Virginia counties. Whereas all other species of dogwood have opposite leaves, with pairs growing directly across from one another on their stems,
the alternate-leaved dogwood is easily distinguishable by a pattern of alternating breaks between its oval leaves. It usually grows no more than 6 feet high, with narrow, 1-inch stems. Its flowers, unlike those of its flashy cousin the flowering dogwood, are tiny clusters of delicate, creamcolored blooms appearing in April and May followed by purple berries in fall that provide food to more than a dozen species of birds and forest animals. This species has also been used in traditional medicines.

Cornus racemosa, or gray dogwood, is less common, though it is found in 24 counties in northern and eastern West Virginia, Kasson says. This dogwood likes to produce many stems and suckers, the older of which take on a distinctive shade of gray. Like most other dogwood species, its flowers are white, appearing in May and June. By summer those blossoms give way to bright green fruits that eventually turn white—a lovely contrast in late summer with its tiny, bright red pedicels, or stems, attached to each fruit.

The most common shrubby dogwood in the state, possibly found in every county, is the silky dogwood, Cornus amomum. This tall shrub thrives in places where land and water meet, such as wetlands and riverbanks. It, too, has small clusters of tightly packed white flowers beloved by pollinators. Its fruit, however, is a striking blue and provides an important food source for animals, especially migrating birds.

Cornus sericea, or red-osier dogwood, is found in 11 counties, typically at higher elevations and in wet environments. Track it down and you may notice its dark red twigs and white flowers, making it a prized ornamental shrub. In fall the red-osier steals the show with red to purple foliage and white fruits.

Cornus canadensis, known as dwarf dogwood or bunchberry dogwood, has been spotted in nine counties, mostly in the east, Kasson says. It prefers
wet soil and cool, mountainous, often coniferous forests, where you can sometimes find it growing on and around old mossy stumps. Tread carefully, should you come across it. This specimen forms a carpet only 10 to 20 centimeters tall. Like its much larger cousin, the flowering dogwood, the dwarf produces a spectacular showing of white, though it appears in late spring to midsummer. By late summer, those flowers will have produced green fruits that ripen to bright, iridescent red and are edible.

If you’re really lucky, you might track down one of our state’s rarest of dogwood specimens, found only in Pendleton and Mineral counties. The round leaf dogwood, Cornus rugosa, ranges from three to 12 feet tall with yellow-green stems, rounded green leaves, and clusters of small white flowers that appear in early summer, giving way to blue or greenish-white fruits maturing in October. This shrub is a host species for butterflies like the spring azure and gossamer wings, while its fruits are a treat for grouse.

A Beauty in Danger

The state’s best-known and beloved dogwood is the flowering dogwood, Cornus florida, first cultivated in 1731. It is also one of our most endangered.

This understory tree is found in oak and hickory forests in 52 of West Virginia’s 55 counties, making it the most common in the state, and has become one of the most popular landscaping plants in the region for
its romantic blooms.

Growing up to 33 feet high and even larger in width, the flowering dogwood’s trunk is rarely more than 6 inches in diameter, with bark resembling alligator skin. Its oval leaves are dark green in spring and summer but turn a rich red-brown in fall. Come April or May, the dogwood bursts into flower with showy, greenish-white blossoms. What appear to be four white-and-blush-tinged petals surrounding each flower cluster are actually modified leaves known as bracts. By late summer or early fall, clusters of small red to yellow fruits ripen and provide food for birds, small mammals, and even deer and bear.

But Vanderhorst says one of this species’ most miraculous feats happens underground. “Flowering dogwood can mine calcium from the subsoil. Calcium is concentrated in the leaves, which benefits land snails living in and consuming the leaf litter, which are in turn important food for birds. Increased calcium in the surface soil also benefits shallow rooted
herbaceous plants.”

Yet this pretty forest shrub has an enemy, one that has been spreading and wreaking havoc for decades. “The single most important pathogen of native
flowering dogwood is Discula destructiva, causal agent of dogwood anthracnose,” Kasson says. The fungus was first reported in 1978. By 1987 it had decimated the flowering dogwood throughout its native range.

“Initial symptoms of dogwood anthracnose are small tan leaf spots that develop into large tan blotches,” Kasson says. “As the disease progresses, infections expand from leaves into small twigs and down to the main stem.” Although the origin of dogwood anthracnose is unclear, it has been theorized that non-native species introduced to the landscape might be one vector.

Rodger Waldman, former president of the Chesapeake Audubon Society, and other landowners in the region have been watching the dogwood’s numbers decline for years. “Most of the dogwoods within the forest interior are dying off, about 80-some percent. Most of what you are seeing now are on the edges or in people’s yards. But we are losing them, too.”

With the decline in calcium-providing dogwood, animals up the food chain, from snails to the birds that feed on them, show signs of decline as well. “Songbird populations are on the decline in the eastern United States,” Waldman says. “One reason they think this is happening is due to lack of calcium in the birds’ eggs. Birds don’t store calcium. When they lay their eggs, they have to eat a lot of sources of calcium for the eggshells to be thick enough to survive.” Two major sources of calcium for birds are the fruits of flowering dogwood and the snails that feed on its foliage.

But it’s not all bad news for this showiest of spring flowerers. The dogwood appears to be fighting back, with a little human assistance. “We found scattered dogwoods that were surviving near the Camp David area in Maryland,” Waldman says. Developed by the University of Tennessee’s Dogwood Breeding Program, a new, disease-resistant native strain has now hit the market. Called Appalachian Spring Flowering Dogwood, it could be the key to keeping this wild beauty thriving.

Waldman highly recommends landowners big and small invest in a few of these plants. He has about 30 growing on his own property. “The more we have growing, the more disease resistance we could have,” he says. “The birds eat the fruit and will spread the seeds. That’s my hope.