Plant This, Not This: Alternatives to Invasive Plants

On By durhammastergardenersIn Uncategorized

By Karen Lauterbach, Master GardenerSM Volunteer

English ivy like the ‘Gold Heart’ cultivar pictured here can revert to green, more aggressive forms and pose real problems in the landscape. (Image credit: Joey Williamson, HGIC Clemson Extension)

I am still regretting some of my plant choices from 30 years ago, especially English ivy (Hedera helix ‘Gold Heart’). At some point, it reverted to the wild type and began spreading across our wooded lot and climbing trees. It has been a years-long battle to bring it under control, and I’m still not sure who will win in the end. It is a tenacious foe.

I wish I had heard the recent Durham Garden Forum talk years ago. Charlotte Glen reviewed common invasive plants in the North Carolina Piedmont and recommended alternatives: plants native to our area and non-natives that are not invasive. Glen is the state coordinator for the NC State Extension Master Gardener program. Glen said that woody invasives – trees, shrubs and vines – pose the most severe harm to our ecosystems. She noted that only a very small percent of introduced species become invasive. But when they do, they can replace native plants, create a monoculture, and change the whole function of an ecosystem. Glen said that by planting natives, gardeners can increase biodiversity and benefit the environment.

So, what are the invasive plants that gardeners in the NC Piedmont should avoid? Two of the top offenders are Bradford pears (Pyrus calleryana) and privet (Ligustrum sinesis and Ligustrum japonicum). What appeared to be the perfect landscape tree – the Bradford pear – has now become the number one tree to avoid. Instead, plant okame cherry (Prunus ‘Okame’), Cornelian cherry (Cornus mas ‘Spring Glow’) or trident maple (Acer buergerianum). Native options include redbud (Cercis canadensis), serviceberry (Amelanchier arborea or Amelanchier grandidfora), sweetbay (Magnolia virginiana) and two-winged silverbell (Halesia diptera). Still available in the nursery trade, privet (Ligustrum spp.) should be avoided. Instead plant cleyera (Ternstroemia gymnanthera), Distylium ‘Linebacker’, holly osmanthus (Osmanthus heteroplyllis), or dwarf burford holly (Ilex cornuta ‘Dwarf Burford’).

Bradford pears are common in our area. This time of year, the extent of their invasiveness is evident as you can easily spot their blooms in landscapes along wooded edges and highways. (Image credit: Jim Janke CC BY 4.0)
Closeup of leaves and flowers of the invasive privet which can either be a shrub or small tree. (Image credit: Megan Hansen CC-BY-SA 2.0)

Emerging invasive shrubs include nandina (Nandina domestica), leatherleaf mahonia (Berberis bealei), and barberry (Berberis thunbergii). For more about these shrubs and what to plant instead, view the PowerPoint slides from Glen’s presentation. 1

Some of the worst invasive vines–in addition to my foe, Hedera helix–are Japanese honeysuckle (Lonicera japonica), Japanese wisteria (Wisteria floribunda), Chinese wisteria (Wisteria senensis), and sweet autumn clematis (Clematis terniflora). Glen said that good alternatives for Piedmont NC gardeners are the following natives: coral honeysuckle (Lonicera sempervirens), Carolina jessamine (Gelsemium sempervirens), and climbing hydrangea (Hydrangea barbara).

Native coral honeysuckle is a pollinator magnet, a favorite for hummingbirds, and a larval host for the spring azure butterfly and the snowberry clearwing moth. (Image credit: Melinda Heigel)

Glen also demonstrated a new resource for North Carolinians: The NC Extension Gardener Plant Toolbox. The Plant Toolbox contains over 4,600 plants that grow in and around North Carolina. The toolbox is designed select plants that will thrive where they are planted. The link to the Plant Toolbox home page is https://plants.ces.ncsu.edu/find_a_plant/.

To join the Durham Garden Forum and have access to a video library of all presentations since 2021, fill out the membership form and mail it with a check for $25 to the address shown. You can find the membership form at https://durhammastergardeners.files.wordpress.com/2022/08/pdf-of-membership-form.pdf. Membership includes discounts at area garden centers (For Garden’s Sake and The Durham Garden Center). Upcoming presentations are listed below.

• March 21: “Propagation” with Sara Smith, Durham County Extension Master Gardener.
• April 18: “Landscape Design,” with Anne Spafford, Ph.D., Professor of Horticultural Science at NC State University.
• May 16: “Plant-to-Plant Interaction,” with Anita Simha, community ecologist and PhD candidate in Duke University’s Program in Ecology.
• June 20: “Bamboo: Uses in the Landscape and Effective Removal,” with David Benfield, founder of Brightside Bamboo. 
• July 18: “NC Native Herbal Plant Remedies,” with Arvis Boughman, a member of the Lumbee Tribe of North Carolina and the author of Herbal Remedies of the Lumbee Indians, and Robert RedHawk Eldridge, who is of Sappony decent and a storyteller. He travels across the country sharing stories about his ancestors and Native American culture.

Notes

1–Link to Glen’s presentation slides https://docs.google.com/presentation/d/e/2PACX-1vRaONT5LdPg6PhsjF2Dv4zw5Yt0ArAa_w5o4k4c0xNbbC3V4XZe1H6AayEL3H4ONsfKBwM1kuL1F-yq/pub?start=false&loop=false&delayms=3000&slide=id.p44

Resources and Additional Information

NC State Extension Gardener Handbook has an through chapter available online about native plants for NC.

https://content.ces.ncsu.edu/extension-gardener-handbook/12-native-plants

The NC Botanical Garden has a great list of native trees, shrubs and vines for your landscape as well as an illustrated online booklet about how to control invasive plants.

https://ncbg,unc.edu/wp-content/uploads/sites/963/2019/08/NativePlantsWoody.pdf

https://ncbg,unc.edu/wp-content/uploads/sites/963/2020/03/ControllingBooklet2020web.pdf

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