When NC Culture decided to do a post on invasive plants in the Piedmont of North Carolina, we had no idea of just how extensive this problem has become. It is massive, folks, and the subject is divided by regions, type of plants (trees, shrubs, etc), exotics or others, severity of threat, and the list goes on! Quite an eye-opener, so we have decided to do five of the more easily recognized invasives, and provide some links for those who would like to know more, as this is a subject that was much larger than we anticipated..
To start off, let us explain what an invasive is: the bottom line is that an invasive plant is an introduced plant that is not native, and is such a rapidly growing plant that it displaces or destroys the native habitat. For a state like North Carolina, with our three distinct regions, we offer a wide range of growing habitats, so are attractive to an equally wide variety of invasives.
Of course, one of our first invasives to mention had to be kudzu, often know as the plant that ate the South! We also picked a few others that might surprise you, such as mimosa? That lovely rather otherworldly tree with the gossamer blooms? Yep, that’s an invasive, too..and we also picked a type of wisteria, English ivy, and mile a minute vine, a plant that truly lives up to its’ name.
Look familiar, North Carolina? One of our worst invasives, the plant that “ate the south”, the lovely kudzu!
Kudzu is a twining perennial vine, and was introduced to the US in 1876 for aid in soil erosion. Unfortunately, the boll weevil infestation caused the plantings to be basically ignored, and kudzu got a toehold on our lovely state, and never let go. An extremely diverse plant, it is not particularly picky about much of (or lack of) anything, the type of soil, or a host of other situations, and can grow on just about anything, anywhere, as the tendrils are especially adept at finding that little teeny crevice and holding on for dear life.
Kudzu basically smothers other plants in its’ path, and the weight of it has been known to even topple trees. Like some ivy plants, everywhere it touches down on soil, it grows a root, making it extremely difficult to eradicate. With a growth rate that can be as much as a foot a day, you can see where it can quickly get out of control, covering buildings, power structures, cell towers, and the like, along with its’ smothering of the plants unfortunate enough to be in the way. Both drought resistant and stress resistant, the vine also has “photosynthetic productivity”, which means, like a sunflower, it moves with the sun in regards to growth.
Although kudzu does have some redeeming value, such as its use as a livestock food, and the starch that is popular in Japan for cooking, there is not much call for it here in the US. All sites that we visited for this post refer to the difficulty of stopping its’ spread or removing it from areas, and the rapid growth has become a major issue in some of our state parks here in NC.
For more information, please visit the kudzu section of NC State University
Mimosas, also known as Persian silk trees, or pink silk trees, are native to Asia. It’s a smallish tree, which adds to the attraction, along with the fragile pink blooms. The blooms actually have no petals, but are produced by many stamens. The tree is highly attractive to hummingbirds, bees, and butterflies, another attractive quality for home gardens.
However, these trees are prolific, and anyone who has seen the seed pods can understand why. Almost like a locust, each pod contains several seeds, and they germinate with little encouragement. The seeds are also viable for quite a while, so a seed dropped one year may not germinate immediately, but it does still have the potential, and once established, the roots can make it a stubborn plant to eradicate. Basically, the problem is that, due to the prolific germination, they just flat choke out any other plant in the vicinity, and take over, and they are not picky about the soil, although they do prefer a dry area.
After reading over several sites, there are a few things we’d like to note if you are still considering planting a mimosa: 1: the mimosa is highly susceptible to wilt, specifically mimosa vascular wilt. They also are known for weak limbs, not a good thing in our storm prone Piedmont. One site that we explored mentioned that folks might want to consider Eastern Redbud or red buckeye as an alternative to mimosa.
For more information on mimosas, please check the mimosa section of the NC State University
Wisteria sure is lovely, isn’t it? However, this IS an invasive…
Thick wisteria vines show in winter at Coker Arboretum in Chapel Hill..Please note: NC Culture is not sure of what variety this is, and we used this particular photo just to illustrate how massive the vine can become.
Chinese wisteria is one of those plants that you just hate to tell folks is an invasive, but it certainly is. Lovely to look at, and it has an aroma of grapes to add to the allure. But if you are considering it for an addition to the garden, please think about a couple of things. For one, wisteria contains wisterin, which has a range of symptoms if ingested, such as nausea, vomiting, diarrhea. The lovely blooms you see here are only visible when the individual plant is changing from a juvenile to an adult plant, however, this stage can take many, many years, as the plant itself can live for over one hundred years. Like the other plants so far mentioned, wisteria basically weakens other plants and trees with its’ weight, and has a smothering quality, destroying the natural habitat for songbirds, etc. One site that provided some solid information was the Piedmont Gardener, and they strongly suggest that, instead of using the Chinese variety, folks consider using American Wisteria, and after looking at the pictures, we could see why..to the untrained eye, there is basically no difference, and yet the American wisteria only grows approximately 2/3s of the size of the Chinese variety, it will cover an arbor with lovely draping blooms, and yet will not cover the nearby woodlands. It does, like the Chinese, need sun to bloom, although it is considered shade tolerant.
We shared two pictures for English ivy, as we wanted to show what can happen when it is unchecked. Having had a little personal experience with English ivy, I can attest to the rapid spread, and have to admit, I am very sorry I ever planted that little teeny plant way back when! I can no longer access two of my water faucets, and snakes have become a problem, as it overgrows very quickly.
The very aspects of English ivy that made it attractive in the beginning as a yard plant are now what also makes it an invasive. It requires little care, can cling via a sticky substance to just about anything, is cold tolerant, and is vigorous! Noted as both a groundcover and a climbing vine, like the kudzu, the weight and lack of light from smothering eventually becomes too much for the plant it is covering, and it weakens and dies. Limbs tend to go first, another problem for storm prone NC.
We would like to also note this: “English ivy also serves as a reservoir for Bacterial Leaf Scorch (Xylella fastidiosa), a plant pathogen that is harmful to elms, oaks, maples and other native plants.”
As alternatives, we also found this..please note that the wisteria suggested in this list is NOT Chinese or Japanese Wisteria, but is “native wisteria“, also known as “American wisteria”, mentioned above.
SUGGESTED ALTERNATIVE PLANTS
A wide variety of attractive and ecologically adapted and beneficial native plants can be substituted for English ivy. Select plants adapted to the level of light available on the site (i.e., full sun, shade, part-shade). Plants that will eventually spread to cover an area of ground include flowering plants like eastern prickly pear cactus (Opuntia humifusa), blue phlox (Phlox divaricata), wild ginger (Asarum canadense), Allegheny spurge (Pachysandra procumbens), and green and gold (Chrysogonum virginianum); ferns like Christmas fern (Polystichum acrostichoides), northern maidenhair fern (Adiantum pedatum), northern lady fern (Athyrium filix-femina), sensitive fern (Onoclea sensibilis), and cinnamon fern (Osmunda cinnamomea); grasses like red fescue (Festuca rubra), wild oats (Chasmanthium latifolium), bottlebrush grass (Elymus hystrix) and switch grass (Panicum virgatum); and sedges like Pennsylvania sedge (Carex pennsylvanica) and tussock sedge (Carex stricta). Native vines that are good replacements for English ivy include trumpet creeper (Campsis radicans), Virginia creeper (Parthenocissus quinquefolia), passionflower vine (Passiflora lutea), Dutchman’s pipe (Aristolochia macrophylla), and native wisteria (Wisteria frutescens)*.
We would especially like to thank the government site for the quotes and suggestions above. You can easily read more by viewing the Plant Conservation Alliance’s Alien Plant Working Group page.
An unusual leaf shape, small white blossoms, and a stongly blue-hued fruit characterize the Mile a Minute vine, also sometimes called the “tearthumb” vine (the tearthumb reference is due to the barb this plant carries). Several sites has information on this particular invasive, and although its’ effect is not particularly funny, we also saw it referred to as a “bio-bully”. As you can guess from the name, it is an extremely vigorous plant, and can quickly smother other native plants, reducing their exposure to light (necessary for photosynthesis), and is of particular concern to Christmas tree farms, etc. Although an annual, it loves to drop fruit to spread.
I do have to say that when researching this particular plant, it was interesting to note that some sites deny its’ presence in our state, and yet other sites report it in Alleghany and also in Wake, to name a couple. To learn more about this stubborn plant, please check this link to our NC Department of Agriculture: Mile a minute.
Please note that these are only invasives that NC Culture felt many would recognize, and by no means touches on the very long list of problem plants. We counted 27 total on only one list: exotics on the severe threat list! So not only do you have the nursery stock that may suddenly colonize that you felt would be a marvelous addition to the yard or garden, but you also have the out of control introduced plants that are costing NC thousands upon thousands of dollars to either eradicate or at the least, keep in check. We are going to include a few links you may find helpful if you have any questions as to the advisability of planting that particular plant..sure wish this admin had read a few of these before I transported some little seedlings from the woods to my yard!
This first link from the North Carolina Native Plant Society had one of the best lists for reference that NC Culture came across…very clearly put, and listed in level of threat, etc. Would highly recommend trying this, especially if you are unsure of the scientific name, and only know the common name. Plus, the highlighted plants on their list have an information link associated with the plant, so you can quickly find out more.
Another page we’d like to mention is the North Carolina Exotic Pest Plant Council. This page had a printable brochure, with lots of information and links on it.
To report invasives, please call 1-800 206 9333 (WEED), or email email@example.com