From Summer 2023 issue of Branching Out. Subscribe to Branching Out here. Read more Invasives in Your Woodland articles here. This article contains information current as of date of publication.
The name “Winter Creeper” suggests that the focus of this issue’s spotlight might grow slowly during the season between autumn and spring. That may have been true in its native habitat in Asia. A general search turns up no particular origin story connected to its name aside from its Latin name (euonymus Fortunei), which is in recognition of the Scottish botanist and explorer Robert Fortune. It is known, however, that the plant was imported to the United States in 1907 as an ornamental ground cover.
In that role, it performs well, and grows vigorously to fill open spaces. But this quality, along with its tolerance of harsh conditions, allowed it to escape from cultivation and to spread throughout much of the eastern states. In Maryland, it is reported in all but three counties (Garrett, Charles, and St. Mary’s). See the map below. Consequently, it has been banned for sale by the state Department of Agriculture as a Tier 1 invasive plant.
What is it?
Winter creeper, also known as wintercreeper, creeping euonymus, or Fortune’s spindle, is an evergreen perennial vine. As noted above, it is a vigorous plant, and it tolerates a wide range of soil types. It grows well in conditions from full sun to deep shade and in soils that are acidic or low in nutrients. It does poorly, however, in heavy wet soils. It can create dense mats and thickets that shade out native plant species, or grow as shrubs up to 3 feet tall.
This vine invades both forest margins and disturbed areas, such as where construction has taken place or where new landscaping has occurred, as well as forest openings that have been created by windstorms, fire, or mechanical thinning.
How does it spread?
Winter creeper can grow along the ground as well as climb into trees. The ground-based vines spread vegetatively, sending out new roots laterally along the main branches to create new plants. Vines that encounter trees may climb to over 60 feet above the ground in search of sunlight. Researchers note that these lead to different behaviors, as apparently only juvenile vines will spread onto trees, and only those that climb produce flowers and fruit when they mature. The fruit can be consumed by birds and wildlife, which then excrete the seeds that colonize new areas.
How can I identify it?
The vines' two growth environments mean winter creeper has two different forms of leaves. While both are dark green, glossy ovals with silvery veins and toothed margins, growing opposite on the stem, the type of oval varies. Leaves of vines growing into the trees are more elongated.
Mature climbing vines can produce flowers in June and July and fruit in the fall. The flowers are small and greenish with five petals. The fruit are small pink-red capsules that split to expose the seeds. See the image gallery below.
How can I control it?
If possible, remove young plants as soon as they are found. Hand-pulling or grubbing with a Pulaski or other tool is effective if the soil is moist and if all roots can be removed. Herbicide applications can be effective when used properly. Cut-stem treatments can kill the vines in trees, and foliar treatments are effective in low-lying infestations.
For more information:
Learn more about winter creeper:
Climbing Euonymus (Plant Conservation Alliance)
Look out for wintercreeper (Maryland Grows Blog)
Evergreen and Creepy: It’s Winter Creeper! (Virginia Native Plant Society)