It’s a cold and damp Thursday morning as Todd Rounsaville leads a band of Arboretum employees and volunteers into where plants would, if given a foothold, take over the state botanical garden.
Even in The Arboretum, with its staff and meticulously tended grounds, the invasive plants never give up.
Honeysuckle clings to the back borders of homes near the Arboretum Woods, a forest area. Invasive-plant fighters hate honeysuckle. They are similarly irked by wintercreeper, a type of Euonymus. And they have done battle recently with invasive pear trees, which have taken up residence in vacant fields across the Bluegrass.
Their tools are varied — loppers, hand pruners and weed wrenches — but more than that, extracting many of the invasive plants requires a strong set of arms and good knees, because there is a lot of kneeling.
Arboretum employee Laura Baird and Cameron Stribling, 15, a student from the STEAM Academy, tug at some garlic mustard plants. With their dainty white flowers, the plants look harmless, but they are invasive, so they have to go.
Why worry about the damage caused by invasive species? Rounsaville, the Arboretum’s native plant curator, says wintercreeper and other plants change the nutrient mix and soil moisture in an ecosystem, and they can make the area less hospitable for native plants.
Wintercreeper climbs trees, where it can kill a tree by strangling its host. Lexington’s urban forestry department recommends that vines such as wintercreeper, Virginia creeper, wild grape and English ivy be cut near the ground and treated with an herbicide to prevent new growth. Lexington’s street-tree ordinance prohibits vines growing on street trees.
A Chinese crabapple, another invasive plant, drapes itself over the sign proclaiming the area the woods section of the Arboretum.
Nearby, Rounsaville spots stalks of multiflora rose, another intruder. Once recommended for erosion control, hedges and wildlife habitat, the multiflora rose grows to become a shrub that chokes out other vegetation and, in shade, will grow up trees like a vine.
An ornamental cherry also ends its run in the woodland area, which is a bit of deep-forest throwback to what used to be common in this area.
Sometimes, the invasive plants are bagged and hauled away. If they aren’t carrying seeds, they can be left on the ground to decay and provide nitrogen for the soil.