Southeastern Wisconsin Invasive Species Consortium, Inc.


Shop Local


Composting Concerns

Is composting invasive plants a good idea?

compostNow is the time of year when many of us are removing unwanted invasive species or mulching to prevent new weeds from establishing in our yards. You may use your local municipal yard waste mulch piles or a home compost pile to help with this work. However, while using composting and mulching options for managing unwanted plants, it is critical to understand the potential impacts of composting invasive species, of using mulch from local brush dumps, and your local government’s policies, in order to reduce the spread of invasive plants via composting.  

In general, the best time to dispose of invasive plants is before plants flower and produce seed. After the fruits or seeds develop, make sure to minimize movement of the plants to prevent unnecessary dispersal. If possible, leave plants on site.  This will reduce the potential to spread invasive plants to un-invaded areas. If you choose to dispose of your plants at a municipal site, and your municipality allows it, it is helpful to understand the biology of the invasive you are composting. 

A recent study by Joe Van Rossum at the University of Wisconsin Stevens Point (unpublished) looks at assessing the ability of municipal compost piles to kill active seeds. Results of this study suggest that up to 99% of garlic mustard and common buckthorn seeds are killed at the temperatures reached by large scale composting. Plants such as garlic mustard, dame’s rocket, and common teasel spread by seed. Woody invasives like common buckthorn, multiflora rose, and autumn olive that lack seeds can be safely chipped.  These should be pulled and left with roots exposed until they have dried out. Once they are fully dead and dried they can be composted or left on site.  If there is any seed material it should be left on site or be placed in a large scale composting system and not simply a brush pile.

invasive-speciesContrary to woody plants and seed material, some species should never be composted because they have rhizomes or other parts that may survive in the compost and spread to new locations when the compost is distributed. Herbaceous plants that spread by rhizomes (horizontal, underground stems) such as Japanese knotweed (pictured at right), purple loosestrife, and reed canary grass should never be composted. The best options for disposing of these plants is landfilling in a clear, plastic bag labeled “invasive species” or burning in accordance with all federal, state, and local laws and ordinances.

If you plan to use your local brush dump or home composting site for your yard waste, it’s important to know the state and local laws regarding invasive species disposal.  It is illegal to dispose of yard waste in landfills in Wisconsin.  However, there is an exception for invasive species.  Wisconsin Administrative Code NR 40 allows invasive species yard waste that is bagged and properly labeled to be disposed of in a landfill.  Along with the State Statues some cities and towns have local policies to help prevent invasive species spread via yard waste disposal sites. You can learn more about what to do with your yard waste and invasive species and your municipality’s policy regarding public brush and composting sites by visiting their website. With a little bit of knowledge you can help clear your land and lawn of invasive species while helping to avoid their spread to distant sites.  Happy weeding!

For additional information on the proper disposal of invasive plants visit:

Compost with Care: How to dispose of invasive plants responsibly

Is That Carrot a Cow or a Hog?

Don’t confuse our native American cow parsnip with giant hogweed

There are all kinds of carrots.  As a matter of fact, the carrot plant family, Apiaceae, contains over 3,000 species, including native types such as American cow parsnip (Heracleum lanatum) and angelica (Angelica atropurpurea), along with non-native invasive species that can cause severe skin and eye irritation, painful blistering, permanent scarring and blindness like wild parsnip (Pastinaca sativa) and giant hogweed (Heracleum mantegazzianum).

Many plants are often misidentified as giant hogweed; the most common of those being our native American cow parsnip. Native cow parsnip is common in our region and provides nectar for butterflies & other beneficial insects. The cow parsnip flowers turn into attractive tan colored seed heads that smell faintly of anise and provide food for birds through the winter.  Only a few populations of the invasive giant hogweed have been found in three Wisconsin counties north of our region and those populations are aggressively managed and monitored.

Here are some tips to help you differentiate between these two species:

For great photographs and more information regarding the characteristics of American cow parsnip, giant hogweed and similar species, and for hogweed control methods, visit New York State Department of Environmental Conservation.  Also, check out this useful video which was created by the Invasive Species Council of Metro Vancouver to help people identify giant hogweed and to be better able to discern it from the native cow parsnip and Giant hogweed control methods from New York State Department of Environmental Conservation.

If you believe you may have giant hogweed growing in your area, contact the Wisconsin Department of Natural Resources.  And, if you happen across a patch of American cow parsnip, stop and appreciate the beauty of this massive native perennial!

SEWISC Assistance Program

2014 Awardees Announced

We are excited to announce that 25 excellent proposals were submitted for funding to the 2014 SEWISC Assistance Program, which was graciously sponsored by the We Energies Foundation.  Although a challenging task, the selection committee chose 5 extraordinary on-the-ground invasive species control projects which will be conducted in our region over the next few months. The projects are summarized  below:

SEWISC awarded $1,000 to the Friends of Lapham Peak for a buckthorn and honeysuckle removal project along the old Government Hill Road in Lapham Peak.  The project will focus on cutting, stacking and burning buckthorn and honeysuckle using volunteers known at the park as the “Buckthorn Busters”.  Funding will be used to purchase equipment and contracted chainsaw work needed to complete the project.  Several long-time partners including members of the Friends of Lapham Peak, the Ice Age Trail Alliance and local school groups such as Kettle Moraine High School will all lend a hand with invasive plant removal.

Riveredge Nature Center (RNC) was awarded $1,000 for a 5-acre vernal pond restoration project in the Riveredge Creek State Natural Area.  The project will focus on the removal and management of reed canary grass. This vernal pond serves as crucial breeding habitat for many reptiles and amphibians and is a hub for biological diversity and educational activities at RNC.  Our funds will be used to compensate RNC staff who will conduct the control efforts with the help of their dedicated volunteer base.


Riveredge Nature Center volunteer crew hand pulling reed canary grass from vernal pond.

A $1,488 award was given to the River Revitalization Foundation (RRF) for invasive species control in the Milwaukee River Greenway. Management efforts will be conducted on 26 riparian acres owned by RRF, as well on riparian land owned by partners, including Milwaukee County Department of Parks, Recreation & Culture, and the Milwaukee Area Technical College. This support will provide RRF with supplies and materials to effectively control common teasel, Japanese knotweed, buckthorn, honeysuckle, reed canary grass, thistle, garlic mustard, and burdock.  RRF works collaboratively with many student volunteers including the Cambridge Woods Neighborhood Association.

SEWISC awarded $1,150 to the Caledonia Conservancy Land Trust for invasive species control on approximately 200 acres of Caledonia Conservancy Lands.  The funds will be used to purchase herbicide and personal protective safety equipment.  This project will focus on eliminating woody invasive species using the Conservancy’s dedicated volunteer base which includes several high schools within the Racine Unified School District as well as the Prairie School and UW-Parkside. The Conservancy Land Trust will also continue to engage local schools by hosting the School to Nature Program at several sites throughout the year.

Last, but certainly not least, $766.50 was awarded to the Silver Lake Management District for a Eurasian watermilfoil control project using divers to eliminate the first small patch of the plant located in Silver Lake, Oconomowoc. The funds provided by SEWISC will be used to purchase SCUBA equipment. The Lake District will engage and educate volunteers through opportunities to help remove and bag the milfoil pulled by SCUBA divers during removal workdays.

Thank you to We Energies Foundation for supporting these vital efforts!we-energies

Wisconsin’s 10th Annual Invasive Species Awareness Month

Protect the Places Where You Play:

Keep Invasives Out!


The 10th Annual Wisconsin Invasive Species Awareness Month (ISAM) will be filled with events such as a video contest, the annual Invader Crusader Awards, the 3rd annual Invasive Species Education Summit, and more.  Click here to browse the statewide online event calendar.

Would you like to have an ISAM event this year?  Here is a Suggestions List that should help you come up with something for your audience and promote it by emailing the ISAM Coordinator to register your invasive species workday, workshop, or other event.  Then check out the Event Leader Resources  for tips on leading and publicizing events.

umiscUpper Midwest Invasive Species Conference

Plan to attend this third biennial conference

The 2014 Upper Midwest Invasive Species Conference (UMISC) will be held in scenic Duluth, Minnesota on October 20-22, 2014.  Attendees will exchange information and expertise on all invasive aquatic and terrestrial plant, animal, insect and pathogen species.

The goal of UMISC is to strengthen management of invasive species, especially prevention, control, and containment.  Expected audience includes: researchers, land managers, natural resource professionals, university personnel, landscape and nursery professionals, agriculture and forestry employees, environmental specialists, lake association members, land owners, government agencies, non-governmental organizations, and anyone interested in managing the spread of invasive species in the Upper Midwest.  Go to: UMISC 2014 for more information and to register.