The mission of the Invasive Plants Association of Wisconsin (IPAW) is "to promote better stewardship of the natural resources of Wisconsin by advancing the understanding of invasive plants and encouraging the control of their spread." A recognized
key to accomplishing this mission is to develop a working list of the
plants that are invasive in the natural plant communities and wild areas
of the state. A listing of the invasive plants of Wisconsin will serve
several useful functions. As stewards of the natural and wild areas of
the state, many of us have watched some plant species become established
and begin to spread at our sites long before we became aware that the
species was already known to act invasively in natural communities. A
list will provide a reference for species that we should consider managing
at an early stage of establishment while they can be effectively controlled.
This list will give IPAW a focus for our educational efforts. This working
list also represents a call for more information about the ecology, distribution and control of the listed species. Several species on the list are well
known to be seriously invasive, and there is a considerable amount of
information about the habitats they invade, their distribution in the
state, and methods for their control. Many other species on this working
list have been observed to be aggressive invaders somewhere within the
state, but little information has been compiled about just what native
plant communities are at risk or effective methods for management. IPAW
is committed to maintaining this list to reflect the most current information
available on the invasive plants of the state.
As more information is obtained some species will undoubtedly be added
to the IPAW list of known invasive plants. Other species may be removed
when it is revealed that they do not pose the threat currently thought
Our "Working List of the Invasive Plants
of Wisconsin" is presented here.
This list is not intended to include weeds, nor does it include plants
that are native to the state. A list of the worst agricultural weeds of
Wisconsin would be useful to some groups in the state, but the focus of
IPAW is plants that invade natural plant communities, and combining a
list of weeds with a list of invasive plants has the potential to create
considerable confusion. If a need is demonstrated for IPAW to catalogue
the weeds of the state, formation of that list will be a separate project.
There are of course some species that are both invasive plants and weeds
(e.g. Canada thistle, Cirsium arvense), and these are catalogued on this
working list. Those non-native species that are not known to be currently
invasive in Wisconsin, but that are invasive in similar ecoregions and
may have the potential to become invasive in the state, are presented
separately in the "IPAW Working List of the Potentially Invasive
Plants for Wisconsin."