Somerset County

AG NEWS

Cornus florida   

Plant of the Week... 

...is also commonly known as Flowering Dogwood, a wonderful native understory tree that grows 15-30 feet tall and wide and thrives in moist acidic, organically rich soils with morning sun and afternoon shade. These spring flowering trees should be planted at least 1-2 inches above ground level and topped with a 1–2-inch layer of mulch to keep the roots cool and moist during the heat of summer. In nature the Flowering Dogwood can be found at the edges of the woods or growing under the larger woodland trees.  The tree’s habit is to spread its branches almost horizontally with a broadly pyramidal or flat top. They begin to bloom before the leaves emerge and when the Redbuds are halfway done blooming.  The flower buds grow at the ends of the branches and are flattened, rounded and are covered by 2 large silky scales, with another 2 inner scales at a 90-degree angle that become showy white bracts.  The true, very tiny yellow-green flowers are gathered in a centered ¾ inch compact button and are surrounded by 4 very showy, pure white petal-like 2-inch-long bracts.  Each bract opens flat and has a rounded notch at the ends. The flowers mature into glossy bright shiny red fruits in clusters of 3-4 at the ends of the branches. They are bitter and inedible for humans but are enjoyed in the autumn by 43 species of birds.   The 3-6 inch oval leaves attach opposite to each other on the stems with curving veins from the base to the tip of the leaf with an entire margin. The fall colors are often red to burgundy, and the stems are green with purple. The bark as the trees mature are grayish- brown to blackish in square and rectangular blocks. The Flowering Dogwood is a host plant for the Azure caterpillar (Celastrina ladon) while many different butterflies feed on the nectar of the tiny flowers. The flowers support many bees including the specialized bees Andrena fragilis (Fragile Dogwood Mining Bee), Andrena integra (Bare Dogwood miner Bee) and Andrena platyparia (Plated Miner Bee) Some of the birds that feast on the fall berries include many songbirds, ruffed grouse, quail and wild turkey.  There are quite a few mammals that also eat the ripe red berries including black bears, foxes, white tailed deer, skunks and squirrels. The trees are hardy in USDA zones 5-9 and are tolerant to deer browsing, clay soils and black walnut trees. The beautiful Flowering dogwood does have its share of insect and disease pests, but mostly when they are stressed in the landscape. Insect pests can include dogwood borer, dogwood sawfly, leaf hoppers, leaf miner, calico scale, Japanese maple scale, and oyster shell scale. Diseases include dogwood anthracnose (which only occurs at 1800 feet or higher elevations), spot anthracnose, powdery mildew, leaf spot, canker, root rot and leaf, twig blight, crown canker, bacterial leaf scorch and septoria leaf spot. There are native and nativar dogwood that are resistant to powdery mildew including ‘Appalachian Joy’, ‘Cherokee Brave’, ‘Jeans Appalachian Snow’. ‘Karens Appalachian Blush’, Kay’s Appalachian Mist’, ‘Weavers White’, and ‘Welch’s Bay Beauty’. 

Ginny Rosenkranz

Extension Advisory Committee