Here’s the top invasive plants to look out for in your Kentucky backyard this spring
From kudzu to your common backyard honeysuckle, invasive plant species are spreading unchecked across Kentucky, crowding out natives and throwing ecosystems out of balance.
If you’re not watchful, some of the more troublesome species, like poison hemlock, can take over your backyard.
We’ve rounded up some tips to help you identify and remove a few of these problematic plants this spring and get a handle on this seemingly never-ending battle.
What makes a species ‘invasive’ and how do they spread?
For a species to be considered “invasive,” it has to meet two major criteria: It must be non-native to the ecosystem it inhabits and it must cause harm.
That’s according to the National Wildlife Federation, which reports roughly 42% of threatened or endangered species on Earth are at risk because of invasives.
To be considered invasive, a species doesn’t have to come from some far-off country. Lake trout from the Great Lakes, for example, are considered invasive in Yellowstone in Wyoming because they compete with native trout. Without the presence of natural predators, parasites, diseases and competitors, invasive species can spread unchecked and crowd out the natives.
Generally speaking, any species that grows and reproduces quickly and spreads aggressively with the potential to cause harm is labeled as invasive.
The damage invasive species unleash extends beyond ecosystems, but to human health and economies as well, with the National Wildlife Federation putting the cost at billions of dollars each year. Healthy native ecosystems underpin many of our commercial agricultural and recreational activities.
Humans are instrumental in the spread of invasive species around the world.
Sometimes, it’s intentional, like the introduction of kudzu to the U.S. in the late 1800s. While they first came here as an ornamental plant, kudzu was later grown as a crop for livestock to forage and to stabilize the soil. Under the right conditions, it can grow 2 inches in a single day. Left unchecked, it can take over woodlands, stream banks and even old farmsteads.
What are the most invasive species in Kentucky?
The Kentucky Exotic Pest Plant Council has identified at least 145 invasive plants in the state and put an additional 35 on its watch list.
Here’s a look at some of the most recognizable invasive plant species, which the Kentucky Exotic Pest Plant Council calls “severe threats.”
As its name suggests, poison hemlock is fatal to humans and animals if ingested. A pretty plant with delicate white flowers that resemble Queen Anne’s Lace or wild carrots, it was the poison used to kill the Greek philosopher Socrates, and it’s spreading in Kentucky.
The stems of the plant have purple splotches, which can help with identifying it.
It exhibits fern-like leaves and its flowers come into bloom in early June. Queen Anne’s Lace, another invader, is similar but not as threatening. It’s sometimes called “chigger weed” for its ability to harbor itchy mites that can spread to your exposed skin upon contact with the plant.
Unlike poison hemlock, Queen Anne’s Lace has hair on its stems and petioles, the part of the plant that attach the leaf to the stem.
Mowing or cutting down poison hemlock is an option, but it should be done before it flowers and produces seed. Spraying is another alternative, and is best done in the spring and fall, when it grows in its rosette shape as a young plant.
Bush honeysuckle refers to several species, but the most common variety in Kentucky is the Amur honeysuckle, according to the University of Kentucky’s Department of Forestry and Natural Resources.
A native of northern China, Korea and parts of Japan, it was first introduced into the U.S. in 1897. Escapees from ornamental plantings were first recorded in the 1920s and promoted for conservation and wildlife uses in the 1960s and 70s.
Though it was once thought it could only tolerate Central Kentucky soil types, bush honeysuckle can actually grow under moderate light conditions and survive in many soil types. Amur honeysuckle is most common in Northern and Central Kentucky, though now it’s spreading across the state.
The Amur species flowers in June, and its white and yellow flowers can produce more than 1 million red seeds on mature (25-year-old) plants, which can grow to be 20 feet tall.
Removing the plant can be tough given the size it can grow to, and methods vary based on the height of the plant in question. Kentucky Woodlands Magazine has information on different approaches to removal, including necessary stump removal.
A native of Asia, this fast-growing tree has spread throughout the U.S. It puts out wind-blown seeds that can sprout and rapidly grow into a large tree.
According to Kentucky Woodlands magazine, Tree-of-Heaven has gray, smooth bark and can grow to a towering height of 80 feet tall if allowed to grow unchecked. Its leaves are pinnately compound and oval-shaped, resembling a tropical palm tree.
Because Tree-of-Heaven puts out root suckers, or small trees that rise from its roots, simply hacking down the trees or pulling them up by their roots may not remove them unless they’re quite small.
More about invasive plants in Kentucky and alternatives
The Kentucky Exotic Pest Plant Council has an extensive list of native alternatives to plant in your backyard instead of invasive plants. A few they recommend include:
Instead of the invasive Tree-of-Heaven, plant the native Kentucky Coffee Tree
Tear down that honeysuckle and plant a native dogwood tree in its place
Instead of English Ivy, plant Virginia Creeper
The University of Kentucky’s Department of Forestry and Environment also has resources to learn about and combat invasive plants in the state.
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