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Invasive Plants: A Threat to Wisconsin's Landscapes

Updated: Jul 8

Have you ever noticed unfamiliar plants taking over natural areas? These are likely invasive species, and they pose a serious threat to Wisconsin's beautiful landscapes.

Non-native and invasive plant species are rewriting our Wisconsin Landscapes, and most of us don’t even realize they are there.

Non-native, invasive plant species are playing a significant role in drastic declines being reported for a wide variety of our Wisconsin birds, native insects (bees, butterflies, moths, beetles) and other wildlife.   

WHY are native vs non-native species so important? 

The easiest and most simple answer is: native plants support native wildlife; they have EVOLVED together over hundreds of million years and they need each other to survive. These plants provide habitat and food for wild life. They also regulate water flow, prevent erosion and provide oxygen while keeping our ecosystem in balance.

Like monarch butterflies, many of our native bees, moths and butterfly species are considered “specialist”. This means they require specific native plants to survive. Birds need caterpillars in the spring to feed their young (they can't feed their young birdseed). Fewer native plants equals fewer (or no) native bees, butterflies, caterpillars, beetles etc, which subsequently leads to a decrease population in birds and other wildlife that depend on them.

The delicate balance of our ecosystem is slowly becoming unstable and unsustainable.

Taking Action: Removing Invasive Species

The WCOLA Stewardship and Resources Committee wants to help fight back against invasive plants. We'll provide information on:

  • Identifying common invasive species in your area.

  • Safe and effective removal methods.

  • Native plant alternatives for landscaping.

How You Can Help:

  • Remove invasive plants from your property.

  • Participate in community restoration projects.

  • Learn more about native and invasive species: WCOLA Stewardship link: here

Below are three important invasive species that should be removed.

Note: the following information is taken from

Wisconsin DNR sites.

JAPANESE BARBARRY (Berberis thunbergii) native to China and Japan - brought to the US as an ornamental.

  • This plant is dangerously taking over our critical woodland understories.

  • It forms dense stands in natural habitats, dominating the forest understory by shading out native plants and changing the foraging habits of wildlife.

  • Research shows infested forests have higher rates of Lyme disease-carrying ticks.

  • White-tailed deer avoid browsing barberry due to the spines, preferring to feed on native plants, giving it a competitive advantage.

  • Very invasive and widespread across the eastern United States and the Midwest.

Mechanical control: Plants can be pulled out or dug up, they are most eccessible in early spring. Remove all roots and watch for resprouts. Cutting without herbicide will result in resprouting. Mow or cut larger plants before seed set if not able to remove the entire plant.

Consider planting Wisconsin native shrub -

Winterberry (Ilex Verticillata) instead of barbarry.



Garlic Mustard (Alliaria petiolata) -Brought from Europe in 1800s for herbal uses and erosion control and is highly invasive. This is a WDNR restricted invasive species, meaning that it is illegal to transport, transfer, and introduce the plant.

  • This plant invades high-quality upland, floodplain forests, savannas, and disturbed areas, such as yards and roadsides.

  • Emerges early in the spring taking sunlight, moisture and nutrition from native plants.

  • Garlic mustard exudes antifungal chemicals into the soil that disrupt associations between mycorrhizal fungi and native plants, suppressing native plant growth.

Mechanical control: You can hand pull in early spring before seed set. If plants are flowering, place them in plastic bags for trash disposal or burn. Cut plants at their base just after the flower stalks have elongated but before any flowers have opened; they may have to cut more than once during a growing season. Place pulled/cut plants in plastic bags for trash disposal.

Consider adding Wisconsin native: WILD GINGER when removing garlic mustard.


Yellow Flag Iris (Iris pseudacorus) -native plant of Eurasia, yellow flag iris introduced as an ornamental plant. This is a WDNR restricted invasive species, meaning that it is illegal to transport, transfer, and introduce the plant.

  • All parts of this plant are poisonous, which results in lowered wildlife food sources in areas where it dominates.

  • This species can escape water gardens and ponds and grow in controlled and natural environments. It can grow in wetlands, forests, bogs, swamps, marshes, lakes, streams and ponds.

  • Dense areas of this plant may alter hydrology by trapping sediment.

Mechanical control:

Small populations may be successfully removed using physical method. Use gloves as may cause skin irritation. All parts of the plant should be dug out – particularly rhizomes and disposed of in a landfill or by burning. Cutting the seed heads may help decrease the plant spreading.

Consider planting the lovely Wisconsin native: Blue Flag Iris (Iris versicolor)


These are just three invasive species important to manage in our landscapes.  Again, to learn much more about invasive plants in our area and how to manage them, please visit WCOLA Stewardship link HERE. Scroll down to INVASIVE PLANTS - RESOURCE GUIDE

The battle against invasive plants is not just about preserving our ecosystems; it's a call to action for each one of us to become stewards of our environment. By removing these invasive species, we pave the way for the environment around us to thrive, ensuring a balanced and resilient ecosystem for our children, grandchildren and generations to come.

Remember, every small effort counts. Whether you're pulling weeds in your backyard or participating in community restoration projects, your actions contribute to the greater cause of preservation.

Together, we can create a world where our native plants and wildlife flourish. Join the movement to remove invasive plants, and help cultivate Waupaca landscapes that are vibrant, diverse, and sustainable.

Nature and people are interconnected, and throughout history humans have shaped natural environments—sometimes for worse, sometimes for better. The Natures Conservatory


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Waupaca Chain O'Lakes Association

Stewardship and Resources Committee

Chair(s): Julie Mazzoleni, Fawn Johnson

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