Invasive Plants – Michigan Association of Conservation Districts

A small but significant number of landscape plants commonly “escape” from planted gardens and invade and destructively alter our natural areas. These species axe dispersed by birds, wind or water. Since people have little or no control of these things, the spread of these plants is very difficult to stop. Once established in the landscape, they crowd out many native plants. These invasive often do extremely well in very broad growing conditions— wet to dry and sunny to shady— making them popular within the nursery trade. An example of a very successful invasive, autumn olive often produces leaves several weeks before the surrounding native plants and keeps these leaves several weeks longer in the fall. This enables it to extend its growing season, an important factor in the plant’s success. When invasives are so successful, they often exclude or crowd out native vegetation. Controlling the invasives is difficult and expensive, and often requires the use of herbicides.

For these reasons, we recommend not using these plants and their varieties and cultivars in your landscape:
 
 

Be wary of “sterile” varieties - we have seen no proof of these claims. In fact, we know that pollen from “sterile” purple loosestrife will fertilize wild purple loosestrife plants.
 
 
 

Appendix E
Problem Prone Plants
Selecting Ornamental Plants – MSU Extension Service

Michigan’s Lower Peninsula Weeds

USFS – Hiawatha National Forest, Conservation Districts, Michigan Association of Conservation Districts, Margaret Boyle.

Information on selected invasive species of the Eastern Region of the US Forest Service. This information has been compiled from various sources. Gleason and Cronquist’s “Manual of Vascular Plants of Northeastern United States and Adjacent Canada” provided information regarding taxonomic authority, common names, habitat and native range. Eastern Region (USFS) invasive plants, ranked by degree of invasiveness, are based on information from States. Voss’s “Michigan Flora” provided information on presence within Michigan’s Lower Peninsula. Degree of invasiveness varies with specific site conditions. Non-natives may be non-invasive in some situations and highly invasive in others. Exotic species that do not appear in this brochure have the potential to be highly invasive. Many species have escaped cultivation and should be monitored.

Categories:
1. Highly invasive
2. Moderately invasive
3. Widespread exotic (non-native)
 

Category I  Plants - Highly Invasive

These plants are all non-native, highly invasive p/ants which invade natural habitats and replace native species.
 
 

Category 2 - Plants - Moderately Invasive

These plants are less invasive than those in Category 1. If these species are significantly replacing native species, then they are doing so only in local areas.
 
 

Category 3 Plants - Widespread Non-native Species

These plants are often restricted to disturbed ground and are not especially invasive in undisturbed natural areas. Most of these species are found throughout much of our range.