Invasive Species

Monona Parks & Recreation Department places a high level of importance on invasive species control in all of the surrounding park areas. Budgets may dictate otherwise, but staff strives for invasive species control as much as possible.

The most common species encountered throughout our park areas are: Buckthorn, Honeysuckle, and Garlic Mustard. You can view the mapped locations of invasive species at Woodland Park here. Other invasive species found in the area may include: Canadian Thistle, Dame's Rocket, Multiflora Rose, Reed Canary Grass, Crown Vetch, and Yellow Sweet Clover. This list could continue on, and helps explain the need for invasive species control.

What is an Invasive?

An invasive species, simply put, is one that can out-compete and overtake another specie(s) in a given area resulting in a loss in diversity and a change or loss in habitat type. An exotic invasive is a species that is not native to the area (for example originates in Europe or Asia) and can very quickly dominate a landscape. The lack of native predators, diseases, or competitors give these species an added advantage as well. Many invasive species also exhibit traits that give them an advantage over the native species of an area: prolific seed production, early to sprout/late to drop leaves, grow in dense shade, inhibit other species from growing nearby.


Humans are the biggest factor in the spread of invasive species. Historically, immigrants brought some species with them from the old world to remind them of home or for cooking purposes. Today most species arrive as hitchhikers or for ornamental purposes. Seeds can hitch a ride in any kind of soil brought in, aquatic species can be transported in bilge water. Ornamental invasives end up being accidental, they were not originally thought to be invasive but end up being so (Norway Maple is a good example of this).

Besides a species being from a different continent or brought by humans, changes in the disturbance regime of an ecosystem can lead to invasive species. For example prairies and oak savanna ecosystems rely heavily on fire to maintain them. Species that normally grow in these areas have become fire tolerant and some even require fire for seed distribution and/or germination. Removal of fire not only inhibits these plants from surviving, but allows for others to move in. Any tree, shrub, grass, or flower that was not fire tolerant can now survive there. Over time this results in the loss of the prairie or oak savanna.

What can be done?

Knowledge of what the invasive species are in your area is very important. With that information you can stop invasive species before they even start by not planting them.
Look at seed contents for invasive species. Prairie seed mixes often contain seeds of invasive species in them.

In areas that already have invasive species in them, there are three main choices for removal/control:
  • Mechanical
  • Chemical
  • Biological

For mechanical removal methods and chemical needs for various invasive species, use the following links:

Midwest Invasive Plant Network Invasive Plant Control Database
Invasive Plants Association of Wisconsin
Wisconsin Department of Natural Resources - Invasive Species
The Nature Conservancy