About 20 years ago, I planted a ground cover that was all the rage at the time. I decided that glossy, dark-green euonymus fortunei, a native of Asia, would be ideal to fill in prettily around shrubs and to block weeds. As years went by, a patch in Red Fox Garden succumbed to scale, and the euonymus at my house had a rude habit of climbing up the garage siding and suckering in until pulled down. However, its dense cover did block weeds, and I liked the look of it.
So, I was not prepared when Cousin David, who has spent years clearing invasive shrubs and vines from the Quarry Farm nature preserve, reported an unfamiliar branching vine climbing in a cluster of trees deep in the woods, well beyond my house and garden. It was neither poison ivy nor wild grape vine, and its leaves looked a little like myrtle, only larger. I made a discomfiting discovery: The invader was euonymus fortunei, my pretty ground cover gone rogue. Looking it up on the internet, I was shocked to learn that euonymus is now generally considered an invasive species, a landscaping no-no.
Horticultural websites discuss the aggressive nature of euonymus fortunei. One example is this from North Carolina State University Extension: “Some cultivars may be more of a vine and others more of a small shrub, but the vining cultivars and some shrubs can both be invasive… Climbing euonymus readily escapes into native forests and has no trouble dominating medium-sized trees. [It] is listed as invasive in North Carolina and in other states of the southeast and northeast. When used as ground cover for the showy leaves, it tends to climb if given support. . . .When this vine climbs trees it produces aerial rootlets along its branches. [Its small white berries] are eaten by some birds which is how the plant is spread and often how it becomes more invasive.” This is surely how euonymus flew from my garden into the woods of the preserve.
My experience with euonymus fortunei has been another hard lesson learned about plant selection over the years. When perusing catalogs and nurseries, I should try harder to temper my feverish impulses with some cautionary reminders: Choose natives to the area, more likely to settle companionably into the landscape. Don’t make impulsive purchases based solely on glowing descriptions, especially if a plant is an introduction, sometimes even a “new, improved” cultivar. Know soil (sand, loam, and/or clay), moisture and light preferences. Know how a plant propagates and spreads, so it can be contained if it sends out runners or produces thousands of seeds per plant. In general, know how it interacts with other plants and wildlife.
Better knowledge about such issues might have prevented invasions of bush honeysuckle and multiflora rose, and too many others, which were thought decades ago to have beneficial uses as wildlife food and cover and as living fencing, but became scourges to field and forest, including The Quarry Farm.
—The Gardener at the Quarry Farm