You know about climate change, air and water pollution, and are most likely aware of a number of other environmental concerns. But do you know about the issue of invasive plants?
No walk in the woods or drive down a neighborhood street happens without encountering invasives. Despite the havoc they are wreaking, they aren’t on most people’s radar. Yet eminent biologist E. O. Wilson ranks them second on his list of the five primary threats to the diversity of life on earth. You can help stop this havoc.
Native plants are the plants that were here when Columbus landed. Nature imposes “checks and balances” on these natives so they don’t go rampantly out of control as non-natives can.
Invasive plants are those whose introduction can cause economic and/or environmental harm. Since Europeans began to colonize this land, many, many plants have been brought in from other parts of the world, accidentally and intentionally, and some have become a problem.
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The Brooklyn Botanic Garden describes the specific problem of invasive horticultural plants, those flowers and trees and shrubs and ground covers we buy to put in our yards, this way:
“Scores of prized horticultural plants brought to North America from other continents have jumped the garden gate and escaped into the natural landscape. These invasive weeds are driving out indigenous species, and in the worst cases are radically altering native ecosystems. Scientists consider them one of the top three threats to the biodiversity of wild lands.”
Invasives are easy-maintenance plants that spread rapidly by generous seed production, suckering or runners, and/or cuttings that root readily. They displace native vegetation, often alter light availability and change soil chemistry, and have other negative effects on the ecosystem.
Most Southerners are familiar with our most famous invasive, kudzu, and with Japanese honeysuckle. Let me introduce you to some others.
▪ Autumn olive (Eleagnus umbellata): spreads by suckers and seed dispersed by birds. (A large plant can produce 200,000 seeds a year.)
▪ Bradford pear (Pyrus calleryana): spreads by animal-dispersed seeds.
▪ Chinese and Japanese wisteria (Wisteria sinensis/floribunda): spreads by seeds and rooted runners; kills trees and shrubs by girdling them.
▪ English ivy (Hedera helix): spreads by runners; when mature forms branches that produce berries that are dispersed by birds. Creates an “ivy desert” where nothing else can grow.
▪ Lilyturf, monkey grass (Liriope muscari): spreads by underground stems and seed. Becoming a more serious threat than many invasive plant experts realize. I’ve seen it growing along the Little River in rural northern Durham County and I’m constantly digging it out of my yard, where it has sprouted from seed.
▪ Nandina (Nandina domestica): spreads by seed and, in some varieties, by underground runners.
▪ Periwinkle (Vinca major/minor): spreads by above-ground runners.
▪ Privet (Ligustrum sp.): spreads very rapidly by root suckers and seed dispersal.
Have any of these in your yard? If so, sever any emotional ties you have to them and get to work!
Besides being a genuine threat to the environment, it’s just not neighborly to harbor plants that leave your yard and invade other yards, parks, and natural areas — kind of like throwing litter out the car window, only the litter doesn’t take root.
Here are other steps you can take to stem the tide:
▪ Volunteer to remove invasives at a local park, land conservancy, or other outdoor space.
▪ Talk with nurseries about discontinuing sale of invasives.
▪ Encourage your friends and neighbors to make responsible choices of what to put in their yards.
▪ When buying plants, don’t rely on your supplier to identify which may be invasive. Use the North Carolina Native Plant Society’s invasives list: ncwildflower.org/plant_galleries/invasives_list . If a plant you’re considering is anywhere on the list, be on the safe side and don’t buy it.
▪ Enroll in North Carolina Botanical Garden classes including Weeds 101(11/7, 2-4 pm) or Gardening for Bioversity (11/17, 2-4), ncbg.unc.edu/adult-programs/ .
Great Britain’s Guardian newspaper states that the huge global biodiversity losses now becoming apparent represent a crisis equaling, or quite possibly surpassing, climate change. You may feel unprepared to make a real impact on big environmental issues, but this is one that each and every one of us can take concrete steps to combat. Please make a commitment now to preserving plant biodiversity on your land and in your community. Start eradicating!
Lynn Richardson lives in Durham.