Interested in learning more about how you can have a positive impact on pollinators when gardening in your own landscape? Join the Durham Garden Forum (DGF) on Tuesday, September 16, 2025 from 7:00 – 8:30 pm for an in-person lecture at the North Carolina School of Science and Mathematics in Durham, NC.
Event parking is free and accessed from the entrance on W. Club and Ninth Street.
This event is free to Durham Garden Forum members and $10 for non-members. Not a member?If you join now through the end of 2025, membership extends to the end of 2026.
2025 Keynote Presenter
Dr. Elizabeth D. Hilborn, writer, scientist, and veterinarian with expertise in honeybee medicine presents “Restoring Eden.“ Dr. Hilborn tells the true story of the sudden loss of insect life on her family farm in our part of North Carolina. An award-winning author and environmental epidemiologist for the US Environmental Protection Agency, she will introduce us to the hazards of systemic insecticides and review the best landscape management methods to support pollinator health.
DGF will raffle off three signed copies of Dr. Hilborn’s book ” Restoring Eden” at the end of the program.
Pre-Lecture Plant Swap
Prior to the keynote address, the DGF will host a participant Plant Swap from 6:00 – 7:00 pm.
Bring your divided plants or extra garden plants to share with DGF members. Please bring plants in some form of container, labeled if possible, and remove any plants not taken at the end of the swap. Be ready to connect with other plant-loving people.
If you have plants to drop off, you can drive up to the main entrance, bear to the left, drop off plants at the plant swap space, then go to the parking lot.
Upcoming DGF Events
The Durham Garden Forum (DGF)is an informal group that meets once a month to enrich gardening knowledge and skill. Meetings are on the third Tuesday of the month from 7:00 – 8:30 pm. Most meetings are via Zoom. Members have access to a video library of presentations, and they also receive discounts at Durham Garden Center, and For Garden’s Sake, and Deep Roots Natives.
Durham Garden Forum memberships cost $25 per year. You can access the membership form here (scroll down to bottom). If you are a DGF member, you will receive invitations to register for each month’s meeting. For new members joining now through the end of 2025, membership extends to the end of 2026.
Dates, topics, and presenters for upcoming DGF lectures include
October 26, 2025 “Using Native Plants In Design” with Laurel Babcock, Extension Master GardenerSM volunteer of Durham County
November 18, 2025 “Growing and Maintaining Camellias” with Brie Arthur, horticulturalist, teacher, and author
December 16, 2025 “The Light Eaters” with Zoë Schlanger, The Atlantic journalist covering science, health, and the environment
January 20, 2026 “Nature’s Action Guide” with Sarah F. Jayne, author, educator, and environmentalist
Questions? Contact durhamgardenforum@gmail.com
Edited by Melinda Heigel, NC State Extension Master Gardener SM volunteer of Durham County
By Jeannie Arnts , North Carolina Extension Master GardenerSM volunteer of Durham County
I have volunteered as a recorder for the New Hope Bird Alliance (formerly Audubon) Bird Friendly Habitat (BFH) team since 2018. The BFH team, consisting of a plant expert and a recorder, visits homeowners’ yards to identify native and invasive plants and make recommendations for improvements to achieve an ecologically beneficial habitat for birds, insects, and other wildlife. Since I have joined the group, plants previously recognized as non-native, non-invasive plants have been moved onto the “Watch List” or “Lesser Threat Invasive” list. Other plants previously considered lower threat have been moved to a higher threat category. The question arises, “What is it that changes a benign non-native into an invasive?
When is a Plant Determined to be Invasive?
Plants are categorized as invasive once they disrupt the ecology of intact, functioning eco-systems, leading to loss of biodiversity and habitat degradation. This results in huge economic damage valued in the billions of dollars to agriculture, forestry, and personal property. Invasive plants compete with our natives for critical and often limited resources like sunlight, water, nutrients, soil, and space. Anyone who has ridden the train at the Museum of Life and Science in Durham and seen the Russian olive shrubs (Elaeagnus sp) overtaking the landscape along the tracks or been on a hiking trail in many Triangle forests and seen the stiltgrass (Microstegium vimineum) engulfing the entire ground cover of the forest floor can easily see the impact of invasive species.
Russian olive shrubs (left) out-compete native plants and dominate riparian areas primarily in central and western USA. Japanese stiltgrass (right) was accidentally introduced into Tennessee around 1919 as a result of being used as packing material for porcelain from China. it has invaded many woodlands in North Carolina. (Image credit: NC State Cooperative Extension)
What Factors Influence a Plant to Become Invasive?
Biologists have been “vexed for decades” by the question of what causes some plants, once thought to be benign, non-invasive exotics, to become a risk to our eco-systems due to their invasive characteristics. The ecologist, Charles Elton, wrote the book, The Ecology of Invasions by Plants and Animals, in 1958 and, more than 100 years earlier, Charles Darwin pondered this question during his voyage on the Beagle (1831-1836). Johnny Randall, former Director of Conservation Programs at the NC Botanical Garden, noted that one reason plants become invasive is that in their new environment, they no longer have natural controls, such as pests, pathogens, and herbivores. This gives them an advantage over native plants that have been part of a region’s ecology for millennia; consequently, the invasives often out compete the natives.1
In addition, a plant’s propensity to become invasive is a function of the plant’s own biology, including a relatively short generational period, large seed production, its ability to reproduce asexually (without the need for fertilization), and having large fleshy fruits, such as those produced by Autumn or Russian olive trees (Elaeagnus sp), privet (Ligustrum sp.) and heavenly bamboo (Nandina sp.) With this latter trait, birds will eat the berries and deposit the seeds far from the original location of the plant.
A non-native, is especially prone to invasion when it sets its roots in a “matched habitat” similar from which it came, i.e., their native ranges tend to have similar temperature extremes, precipitation levels, and seasonal cycles. Stiltgrass (Microstegium vimineum) is an example of a plant that meets most of the criteria for becoming invasive. It is an annual that produces up to 1000 seeds per year, has no natural controls, reproduces asexually, and its seeds are distributed by the wind. In addition, the seed bank may take up to five years to germinate. Many gardeners who think they have eliminated stiltgrass on their property one year are befuddled to find a number of plants from the seed bank sprouting the next summer. The good news is that if you continue to manage the stiltgrass, you will have fewer plants each year.
Beloved Plants that Become Invasive
I think we can all agree that we want stiltgrass eliminated from our property, but there are non-native plants that have been beloved by gardeners for generations that are being added to the invasive lists, much to the consternation of gardeners. One example is the lenten rose (Helleborus orientalis).
Some hellebores have started to escape into woodland areas and are able to stifle our favorite native understory flowers. They prevent seedlings of other plants from getting established as dense mats of their offspring grow. (Image credit: NC Extension Toolbox, Bob Gutowski CC-BY-NC-SA-2.0; Jim Robbins CC-BY-NC-4.0).
There are many good reasons that hellebores are such a beloved plant: they bloom over the winter months when very few other plants are blooming; they require little care; they are deer and rabbit resistant; they tolerate a wide range of light conditions; including light shade; and they survive even deep frosts. Unfortunately, they meet many of the conditions that place them at risk to become invasive in our region: they have no natural pests or pathogens; they can successfully fertilize themselves (although bees will seek nectar and pollen from the plants); and they produce a multitude of fertile seeds. While there is not a perfect native substitute for hellebores, the gardener may consider planting a matrix of sedges (Carex species), coral bells (Heuchera americana), and ferns, many of which are host plants, to provide winter interest .
While not yet on the invasive lists in N.C, another beloved plant that is of concern is the crape myrtle (Lagerstroemai indica). Its spread is being tracked in Southern states by the Invasive Atlas of the United States and the plant’s spread is being watched with caution by conservationists in N.C. Each flower of the crape myrtle produces a prodigious number of seeds that are carried or blown far from the mother plant. I have had a crape myrtle in my yard for probably the past 40 years and it has only been recently that I have seen it sprouting up elsewhere in my yard and ¼ acre woods.
Crape myrtles are seen along roadways and in gardens in North Carolina but conservationists have raised concerns because it outcompetes many native plants (Image credit: NC Plant Toolbox, skdavidson)
Liriope (Liriope muscari and L. spicata), bugleweed (Ajuga reptens), Rose of Sharon (Hibiscus syriacus), and ox-eye daisy (Leucanthemum vulgare) are all common ornamental plants that have been added to the NC Invasive Plant list as “Low Threat” species. While they have the potential to harm our local ecology, they are not yet doing so.
Liriope (Liriope muscari), bugleweed (Ajuga reptens), Rose of Sharon (Hibiscus syriacus), and ox-eye daisy (Leucanthemum vulgare) are plants that many of us have in our garden. They are considered to be “Low Threat” to native plants of North Carolina. (Image credit: North Carolina Toobox, Manuel-CC-BY-2.0; Jim Robbins-CC-BY-NC-ND; Frank Mayfield, CC-BY-SA-2.0)
As gardeners, we can control the spread of potentially invasive plants in our own yards or we can choose to remove them and plant a native that supports our native ecology. A follow-up blog will suggest options to consider for replacing invasive plants with natives that power our ecosystems.
Notes
Personal communications Peter Schubert, NC Invasive Plant Council, October, 2024 and Johnny Randall, former Director of Conservation Programs, NC Botanical Garden, October 2024.
Grzędzicka, E., Assessment of Habitat Selection by Invasive Plants and Conditions with the Best Performance of Invasiveness Traits, February, 2023. https://www.mdpi.com/1424-2818/15/3/333
