The Red Twig Dogwood (Cornus sericea) is a favorite among gardeners for its dramatic, year-round appeal. This deciduous shrub is highly valued for its striking, brightly colored stems, which provide intense red color against a snowy backdrop during winter. It features creamy white flowers in late spring, followed by white or pale blue berries that offer food for local wildlife. Its adaptability to wet conditions and its multi-stemmed, thicket-forming habit make it a popular landscape choice.
Defining Its Status
An ecologically invasive species is defined as one that is non-native to a specific ecosystem and whose introduction causes environmental or economic harm. Since Cornus sericea is native to vast expanses of North America, ranging from Alaska and Canada down to Virginia and New Mexico, it cannot be classified as ecologically invasive within that range.
Gardeners often use the term “invasive” colloquially to describe any plant that spreads rapidly or requires frequent maintenance. A plant that is native but spreads quickly is accurately described as “aggressive” or “vigorous.” The Red Twig Dogwood is an aggressive native plant that can easily overpower other species in a cultivated garden space. Understanding this distinction is important for managing the shrub without unwarranted concern over ecological damage.
Understanding Aggressive Growth
The vigorous spread of the Red Twig Dogwood is a natural characteristic rooted in its biology. Its preference for moist habitats, such as streambanks and wetlands, led it to evolve a highly effective method of vegetative reproduction. Its roots form a shallow, branching system that actively produces underground stems, known as rhizomes, from which new shoots or suckers emerge.
This underground network allows the plant to form dense, spreading colonies or thickets, which helps prevent soil erosion in its native environments. The shrub is also stoloniferous, meaning its lower, horizontal branches can root where they touch the soil, further expanding its footprint. This rapid, outward expansion, which can add up to two feet of spread annually, is why the dogwood is viewed as aggressive in a contained garden bed.
Managing Spread in the Landscape
Controlling the aggressive spread involves a combination of root management and strategic pruning. One effective containment strategy is to regularly “root prune” the plant by using a sharp spade to cut through the spreading roots just outside the desired boundary. This process severs the rhizomes, preventing new suckers from emerging in unwanted areas. For permanent containment, installing a physical root barrier or deep edging material around the planting area can prevent the underground stems from escaping.
The intense red color of the stems is brightest on the newest growth, making regular pruning necessary for aesthetics and size management. The most intensive method is called coppicing, where all stems are cut back to within a few inches of the ground in late winter or early spring every two to three years. Alternatively, gardeners can remove one-third of the oldest, dullest stems each year, which rejuvenates the plant while maintaining its overall size. Planting the shrub in areas where it has plenty of room to spread naturally, such as along a property line or a slope, minimizes the need for intervention.