Invasive Species

Invasive Plant Species
Think of invasive species as “bullies”—they don’t play nice with others. An invasive plant species is one that is usually non-native to an area and spreads rapidly, choking out other flora in the battle for survival. These “exotics” may be pretty, but they can also be devastating to our unique local ecosystems.

See a list of the most invasive trees and shrubs...


Norway maples are a good illustration. These attractive shade trees have been a staple in garden centers for years because they grow well in many conditions. Unfortunately, despite its good looks and hardiness, it releases chemicals to discourage undergrowth. If you have a Norway maple, you may have noticed a muddy spot under it. Likewise in natural settings, Norway maple seeds can propagate in a wide variety of conditions and quickly choke out the native undergrowth plants that help prevent erosion. There is plenty of evidence of this at the Indiana dunes, where Norway maples are popping up all over, threatening to convert the various unique habitats found only at the dunes into stands of Norway maple with deep shade and little else.

Because Norway maples have been so popular, the city too has many planted in public areas. However recent awareness of the damage they cause to fragile ecosystems has led to Norway maples' exclusion from any new city planting projects since the early 90s. With such a wide variety of native and non-invasive species more readily available for landscaping, homeowners too can help keep Norway maples out of our urban forest where they can spread to natural settings. What's more, these native species look better during our hot summers than the Norway maple, whose leaves tend to curl and look crispy.

See a complete list of recommended trees…