CLIMATE CHANGE
Climate change is reshaping ecosystems worldwide, and Vermont is no exception. With warmer winters, longer growing seasons, and shifting precipitation patterns, the state’s native landscapes—and the gardens within them—are undergoing significant transformations. For gardeners, these changes present both challenges and opportunities because of the type of precipitation we receive. Rain, ice, freezing rain, snow.... they each influence how we garden.
Vermont’s gardening culture is a cherished tradition, providing beauty, food production, and a connection to the natural world. The downside however is that changing climate has made the state more hospitable to invasive plant species that thrive in longer, warmer seasons and survive the accompanying milder winters. These invasive plants, once held in check by Vermont’s historically cold, below zero-degree winters, are now spreading rapidly, outcompeting native plants and disrupting ecosystems. As I grew up in mid-state Woodstock, Vermont in the middle fifties on into the late 60s, winter temperatures were often -20° to -30° and those walks to and from the bus stop were formidable. We even saw it colder than that at times. Winter 2023 here in Marshfield had one -5° night all winter and I only plowed the driveway 4 times as snowfall was limited too.
Many gardeners remain unaware of the ecological damage caused by these new arrivals. Invasive species crowd out native plants that support pollinators, reduce biodiversity, and alter soil health, threatening the delicate balance of Vermont’s ecosystems. By understanding the impact of these changes and adopting thoughtful agricultural practices, both home gardeners, professionals, and all farmers can play a vital role in preserving Vermont’s agriculture.
Section II: The Impact of Warmer Winters and Longer Growing Seasons: Who else lives here now?
Vermont’s winters, traditionally long and harsh, once acted as a natural barrier to many invasive species. But as winters grew milder, species that couldn’t previously survive here are now thriving. Longer growing seasons give these invasives a head start, allowing them to spread aggressively and disrupt native communities. The invasives we see surviving now include plants, insects and animals.
Some of the most concerning plant species benefiting from Vermont’s changing climate include:
Buckthorn: Grows as a shrub or smaller tree with thorns and black fruit. (https://vtinvasives.org/news-events/news/spotlight-common-buckthorn)
Burning Bush/Winged Euonymous: Introduced as an easily shaped shrub with colorful red-orange, pink and yellow fruit that is popular with birds, hence invasive due to widespread seed distribution and growth. (https://vtinvasives.org/invasive/burning-bush-or-winged-euonymus)
Common Reed: A vigorous reed to 9 feet tall, prominent in roadside ditches, stream and river beds, and other damp to wet areas. Spreads quickly by abundant seeds that travel easily by wind. ( https://vtinvasives.org/invasive/common-reed)
Common Thistle:(https://www.invasivespeciesinfo.gov/terrestrial/plants/canada-thistle) (https://youtu.be/TOvcv3esV4g) A wonderful pollinator plant that is regularly adorned with varieties of butterflies and wild bees. The stems are covered in prickers that make hand pulling difficult.
Garlic Mustard: Capable of surviving Vermont’s mild winters, this invasive crowds out native wildflowers such as trilliums and produces chemicals that inhibit the growth of surrounding plants. (https://vtinvasives.org/invasive/garlic-mustard)
Goutweed/Bishop’s Weed/Snow on the Mountain: Originally introduced as a garden groundcover, the green and white variegated leaves being the most popular however all plants are seriously invasive as one ¼" piece will regenerate. Now found growing through old pastures and along forest lines. Accepts shade in its now expanded territory. (https://vtinvasives.org/invasive/goutweed-or-bishops-weed)
Asiatic Bittersweet: A fast-growing vine that smothers trees and shrubs, damaging forest ecosystems. In the past century it has spread from New Jersey-New York-Pennsylvania northward to Canada. Seeds are dispensed by birds so it is often found growing in old apple orchards which over time it will kill. The vines are often harvested in the fall and made into wreaths but that very popular process contributes to the spread of the vines. (https://vtinvasives.org/invasive/bittersweet-asiatic)
Japanese Knotweed: A tenacious plant that thrives in disturbed soils, displacing native vegetation including wildflowers along waterways and roadsides. Climate change has brought more flooding so this vigorous grower is distributed far and wide and seeds of pieces as small as 1/8” root and grow. This has become a disaster for organic farmers who often grow food plants along rivers where one flood can destroy the organic potential of the land. (https://vtinvasives.org/invasive/knotweed-japanese)
Japanese Barberry: The most vigorous of all the barberries. Popular with birds so it can be found spreading across abandoned farmland, hillsides, along waterways, and in residential settings. The bushes are covered in thorns which keep humans and domestic and farm animals away. This provides a protective opportunity for mice, voles and moles to thrive. Such rodents are critical to the life cycle of Lyme Disease which requires the Blacklegged Deer Tick. (https://vtinvasives.org/invasive/barberry-japanese)
Purple Loosestrife: Noticeable in North America in the early 1800s and now an obvious plant, growing to 3 feet tall with purple blooms. Grows in ditches, damp fields, marshes and along ponds. Confused with Common Liatris found in many flower gardens. (https://vtinvasives.org/invasive/loosestrife-purple)
As invasive plants take root, they displace native plants such as milkweed, goldenrod, and aster—critical sources of food and habitat for pollinators such as bees, butterflies, and hummingbirds. They crowd out trout lilies, wild ginger, trillium, rattlesnake plantain, and wild orchids. The loss of these plants directly contributes to declining pollinator populations, which affects not only individual ecosystems but also crop yields for fruits, vegetables, and flowers.
Section III. The Impact of Invasives on Native Plants and Pollinators.
Invasive insects are another significant consequence of Vermont’s warming climate. Milder winters enable species that once couldn’t survive here to establish themselves, causing extensive damage to forests, gardens, and agriculture.
Here are some examples of insects fairly new to this part of New England which have already shown their destructive capabilities over short periods of time.
Emerald Ash Borer (Agrilus planipennis) (https://www.aphis.usda.gov/plant-pests-diseases/eab): This beetle, previously restricted by Vermont’s cold winters, now poses a severe threat to ash trees statewide. Its larvae burrow into trees, disrupting nutrient flow and eventually killing the trees. Ash trees are important to Vermont’s economy via its use as lumber and firewood. Historically the bark of the brown ash was critical to indigenous peoples for making baskets, and buckets for maple syrup production. Finally, the loss of ash trees due to the emerald ash borer disrupts forest canopies, exposing understories to invasive plants such as knotweed and bittersweet.
Spotted Lanternfly (Lycorma delicatula)(https://www.aphis.usda.gov/plant-pests-diseases/slf): A recent invader, this colorful insect targets a wide range of plants, including grapevines, maples, orchard fruits, and ornamentals. It weakens them and leaves them susceptible to disease. The fruit and maple syrup industries represent a large part of Vermont’s economy. Spotted lanternflies can quickly devastate vineyards, fields and orchards, creating economic and ecological challenges for both gardeners and farmers.
Hemlock Woolly Adelgid (Adelges tsugae)(https://www.invasivespeciesinfo.gov/terrestrial/invertebrates/hemlock-woolly-adelgid): Warmer winters have allowed this pest to spread across Vermont’s hemlock forests, leading to tree mortality and ecosystem collapse in affected areas. Hemlock declines changes soil and water conditions, making it easier for invasive plants to spread in these newly vulnerable areas. Historically hemlocks have provided very useful lumber for projects such as docks, walkways and bridges
in, on or near water.
Beech bark disease is caused by the wooly beech scale or felted beech scale in conjuction with one or two Neocentrix fungi. The tiny scale make holes in the bark so the fungi can enter and over a few years the bark begins to crack and the tree begins to die. Beech trees are a valuable wood for the furniture industry and the wood is also a high BTU firewood. The wood becomes punky and useless as firewood after it has been infected over only a couple years. (https://www.invasivespeciesinfo.gov/terrestrial/pathogens-and-diseases/beech-bark-disease)
Asian Longhorn Beetle, Anoplophora glabripennis, is another wood boring beetle that seeks out hardwood trees including maples, birch, elm, chestnut and willows. In recent years, detection has not determined any beetles in the area of Marshfield where we live but beetles have been located in Massachusetts, and southern and western New Hampshire. Vermont produces more maple syrup and related maple products than any other state in the US. (https://www.invasivespeciesinfo.gov/terrestrial/invertebrates/asian-long-horned-beetle)
Spongy Moth. The caterpillars (Lymantria dispar dispar) continue serious outbreaks in various portions of Vermont. Estimates of 50,000 acres of defoliation occurred in 2021 and in 2022, and have been noticeable in lesser ammounts in 2023 and 2024 perhaps due to wet spring weather in the latter two years. The caterpillars have a a big impact on oak trees but also prefer maples and poplars but will attack spruce and hemlock which are not preferred unless other foliage declines. (https://www.aphis.usda.gov/plant-pests-diseases/spongy-moth)
Animal Changes Two noteworthy changes in the past 8-9 years involve Oppossums (https://en.wikipedia.org/wiki/Opossum) and Jumping Worms (https://www.invasivespeciesinfo.gov/terrestrial/invertebrates/asian-jumping-worm) . Warmer winters have encouraged possums to move northward and I have seen them as far north as St Albans, Vermont in the west, and St Johnsbury, Vermont here on the more eastern side of the state. They have been obvious here at our home which borders Groton State Forest off Route 232 that runs north to south off Route 2 in Marshfield. One of a possum’s interesting and positive behaviors is that they eat ticks. Deer mice and the Blacklegged deer tick are part of the life cycle of Lyme Disease which has become a serious human health hazard for which there still is no immunization.
Jumping Worms, Crazy Snake Works, Alabama Jumpers are some of the names for the same night crawler-sized worm that came to us from Asia. This worm get it various names because when disturbed, it rolls around with great speed and might appear to jump. In the fall of each year the mature worms lay egg cases and then dies over the winter. Come spring the eggs hatch and the worms quickly grow. The speed with which they mature is amazing but is caused by the fact that they eat all the organic material on the forest floor. They are so successful eating all the leaves and composting soil on the forest floor that they devour all the seeds and seedlings of wildflowers, trees and shrubs. This is especially concerning to maple syrup producers since forest floor compost in a sugar orchard is critical to the health of the maturing and sap producing trees, and the seedlings that will become the future’s syrup producers.
Section IV. Big Ecological and Gardening Impacts: What Can We Do?
The dual threat of invasive plants and insects compound each other. Vermont loggers, farmers of all persuasions, and home gardeners can take the following steps:
Learn to Identify and Monitor Invasives
Familiarize yourself with local invasive plants and insects. The Vermont Invasives website (https://vtinvasives.org/) offers excellent resources for identification and reporting.
Regularly inspect your garden and surrounding areas for signs of invasive species. Early detection is key to preventing their spread.
Plant Native and Climate-Resilient Species
Choose native plants such as milkweed, bee balm, asters, and goldenrod to support pollinators.
Incorporate climate-resilient varieties that can thrive in Vermont’s changing conditions, reducing the risk of invasives gaining a foothold.
Manage Invasive Plants and Pests Responsibly
Remove invasive plants carefully, ensuring roots are fully extracted and disposed of to prevent regrowth.
Use traps, barriers, or biological controls to manage invasive insects instead of chemical pesticides, which can harm beneficial insects.
Support Community Efforts
Join local conservation groups or garden clubs working to combat invasive species.
Report sightings of invasive insects like the spotted lanternfly or emerald ash borer, or invasive plants to Vermont’s Department of Agriculture or Forest Service.
Share what you see and what you learn with other gardeners and farmers.
Call to Action
Gardening is more than a hobby; it’s an opportunity to protect Vermont’s ecosystems and biodiversity. By taking proactive steps to combat invasive species, and planting for the future, gardeners can be powerful allies in the fight against climate change.
Join the movement to protect Vermont’s gardens and landscapes! Visit other gardens, nurseries, orchards and fruit, vegetable and flower farms.
Teach your children what you have learned and teach them to be good gardeners too
