Foray of the Month – Climbing the Vineyards • Yellow Springs News
CHow common are invasive plants in Yellow Springs?
“Bittersweet is in everyone’s yard I’ve visited,” local horticulturist Bob Moore said in a recent interview.
The Asian bittersweet plant is one of 38 species on Ohio’s official invasive plant list. Plants on the list are prohibited from distribution and sale. But there are also other invasive processes being studied and monitored for their negative impact on local landscapes.
Don Cipollini, a village and Wright State professor and former member of the Ohio Invasive Plant Council, studies native and non-native species of euonymus. Although not on the state’s official invasive species list, some euonymus species are a significant problem locally, he said.
A range of non-native invasions – from weeds and climbing vines to woody shrubs and trees – thrive in local yards and alleys. These plants can quickly take over a landscape, crowding out native plant species and depriving insects, birds and other animals of habitat and food. Non-native invasive plants already threaten parts of Glen Helen and other reserves in the area.
So what to do?
The News continues our recent coverage of invasive plants with a new series called “Invasion of the Month.” Each article will focus on one or more invasive plant species, with practical tips for managing or removing the plants. Species were selected in consultation with Glen Helen.
This first installment looks at two climbing vines: wintercreeper and Asian sweetheart.
How to identify
If you see something green in winter, it’s likely wintercreeper, an invasive, non-native species of euonymus. (Another invasive euonymus species, a burning bush, distinguished by its red leaves in the fall, will be featured in a future story.) Wintercreeper is a popular landscape plant that has been widely used in the village as a “low-maintenance” ground cover. According to gardener Moore, who farms 20 acres in Agraria, as well as running a local landscaping service.
“Every planting needs some maintenance,” he noted.
Small, dark green leaves and dense growth creeping along the ground define this plant. Wintercreeper also appears as a shrub growth reaching about three feet in height. Trees can be seen growing in abundance locally, and when the plant enters its adult stage, it changes shape and forms flowers and seeds, according to Cipollini.
“This is when you really want to worry about it,” he said.
It’s a little difficult to recognize Asian sweets, according to Moore. Its oval leaves “look really similar to everything else,” he said. This is most noticeable in the fall, when its leaves fall and the bright red berries and yellow seed pods make the plant attractive to some who make wreaths and other decorations from the vine. Unlike wintercreeper, Asian bittersweet does not grow above ground, but climbs vigorously above the canopy, at the expense of trees.
There is also a local bittersweet species, the American bittersweet, which is not inherently invasive, but the Asian variety is more common locally.
Impact on the local scene
Wintercreepers are a big problem in the Glen area, according to Executive Director Nick Pottis.
“We see a lot of that,” he said. “The situation in the Glen is worse than in any other nature reserve,” he added, at least by the consensus of land managers in the area. Glen Helen’s proximity to the village makes the reserve particularly vulnerable.
As for Asian sweetgrass, that vine is widespread “all over the Glen,” especially in the younger forests and near the outdoor education center, Bottis said.
Euonymus can only spread so far on Earth, according to Cipollini, which makes it a concern but one that can eventually be contained. However, when the trees grow and produce fruit, the plant can be spread by birds.
“This is when you enter the pristine landscape,” Botes noted.
Euonymus climbs, but does not typically choke trees, although trees can struggle because of the anaerobic environment the vine creates, according to Moore. In contrast, Asian candy can be fatal to annuals, perennials, shrubs, shrubs and mature trees on which it grows over and over again.
“It chokes the trees and encircles them,” Moore said.
Bittersweet vines are snake-shaped and tangle in on themselves, forming a heavy mat that can suffocate seedlings and take down larger trees, as well as making trees more vulnerable to wind and ice. Additionally, the presence of bittersweet densely woven into the canopy blocks light from grasses and perennials to the ground.
Bittersweet grows enthusiastically, reaching 25 feet tall annually, according to Moore.
How to manage
For bittersweet Asians, the consensus seems to be: get rid of it. But just cutting the vine at the base won’t work.
“He’s going to come back strong,” Moore said.
He recommends digging the vine from the ground where it grows, as well as cutting or uprooting it from shrubs or trees. But since the bittersweet tightly envelops its host, care must be taken not to drop the branches of the tree at the same time.
Other methods include using small amounts of herbicides or alternative treatments such as vinegar. Cipollini suggests cutting the vine at the base and then coating the base with an herbicide such as Roundup. Various combinations of vinegar, dish soap, and water (recipes available online) can be used instead.
“I’m not a huge advocate of herbicides,” he said. “But for controlling invasive plants that themselves pose a form of environmental damage, using a small amount can make sense.”
Those concerned about the impact of herbicides on local landscapes may be able to extract vines with hard work and perseverance, Moore says. That’s the approach being taken in Agraria, where 1,000 pounds of euonymus were recently removed by volunteers.
As for the wintercreeper, opinions differ on whether the plant can be safely kept as a ground cover, provided it is kept away from trees. Moore, who does not use wintercreeper in his landscaping practice, advocates mowing and cutting back spots on the ground to prevent it from spreading.
“If it’s just used to cover the bed, it’s not invasive,” he said.
However, euonymus can form a thick carpet on the ground that prevents the growth of native species. Whoever wishes to lift it off the ground can lift it by hand; A shallow-rooted plant, it emerges fairly easily and dies with repeated pulling and shearing.
Dealing with euonymus that has already climbed trees is a different matter. Once the vine climbs, it must be cut to prevent it from being scattered by birds, according to local experts. Cipollini recommends cutting the wintercreeper at its base and coating the base with a small amount of herbicide. Those who do not wish to use herbicides can extract the plant by the root or cut it repeatedly; Over time, the plant will lose its strength.
Unlike bittersweet, euonymus vines that remain in the tree can be left to wither and eventually fall.
“They will die and fall slowly,” Cipollini said.
Because the euonymus is attached to the tree by many small “fingers,” pulling them from the tree can strip away the bark, damaging the tree, Moore warned.
Only young green vines can be pulled safely; Older, woody trees should be left alone after cutting the vine at the base.
Wintercreeper and Asian sweetgrass can be substituted for local species. The Ohio Department of Natural Resources recommends four species of vines native to North America to replace invasive vines: heartleaf pepper; Clematis is called maiden’s trellis; Trumpet honeysuckle, different from the invasive honeysuckle species that plague our area; and Virginia creeper. Moore added to that list the American wisteria, which is less aggressive than the more common Asian wisteria.
Karen Reed, co-owner of Stoney Creek Garden Center, just north of Yellow Springs, said this week that many of her clients are looking for alternatives to wintercreepers, ivy and other ground covers. She recommends larger shrubs that tolerate shade or part sun and shade, such as oak leaf hydrangea and native hydrangea. Boxwood, which is evergreen and does well in shade, is another good choice.
“It even grows under walnut trees,” she said.
Then there are the hosts. It is found in abundance in the village, and it is very hardy and loves shade. Although they are not a native species, they have not been shown to behave aggressively, according to Cipollini.
“They’re not native, but they’re very benign,” he said.
The next “invasion of the month” is Japanese grass which will be highlighted in August.
Read our previous two-part news series on the invasive plant problem in and around Yellow Springs:
Part One: “The Green Death and Other Invasions”
Part Two: “Good Green, Bad Green”