Southeastern Wisconsin Invasive Species Consortium, Inc.


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Non-invasive choices for gardeners


While browsing through nurseries, retail garden centers, farmer's markets, and garden club plants sales, residents have the opportunity to purchase beautiful, new and exciting plants for their yards and patios.

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Our local nurseries and garden centers offer many beautiful and exciting native plants and non-invasive cultivars to please the esthetic preferences of Wisconsin gardeners.
The availability of invasive exotic plants by sellers has decreased dramatically since the implementation of Wisconsin's Invasive Species Rule (NR 40) in 2009. As a result, the public can feel much more comfortable about statewide efforts to control ecologically destructive invasive plant material.Non-invasive choices for gardeners 2

As with any new regulation, it takes a while for the information to reach all individuals who are impacted by the legislation, so while shopping this season, you may still find an occasional regulated species that should not be sold under NR 40.

SEWISC, along with other Wisconsin Cooperative Weed Management Areas and the Wisconsin Department of Natural Resources (WDNR) continually strive to educate private citizens, land managers, and landscape and nursery industry personnel about the list of plants that are now regulated statewide due to their invasive characteristics.

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Unfortunately, a few regulated species continue to be marketed to the public. Consistent education is essential to eliminating the sale and spread of these species.
Because the names of plants sometimes change, a list of the synonyms and common names for regulated plants and their cultivars has been created by the WDNR to help reduce confusion about which species are and are not legal to sell in Wisconsin.  This list can be found online at:

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), in partnership with WDNR, communicate with all licensed, regulated nurseries annually concerning NR 40 regulated species.  

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In partnership with Wisconsin Coastal Management Program, Wisconsin Energy Corporation Foundation, Natural Resources Consulting, Graef, The Sigma Group, Endeavor, Applied Ecological Services, JF New, and Bergner Associates, SEWISC recently offered NR-40 workshops to park, highway, railroad and utility right-of-way directors, managers and staff.
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There are nine DATCP Nursery Inspectors who each work within a region to inspect licensed nurseries for plant pests and diseases and are now also checking for regulated plants.  However, some venues that sell plants are not licensed nurseries.  Outreach efforts hope to fill this void in part by educating farmers’ market coordinators each season in English and Hmong.  Visits are also made to retailers offering aquatic plants for water gardeners.

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  A few regulated exotic invasive plants continue to be marketed to the public at farmer's markets and used in seasonal arrangements by garden clubs. Consistent education will help to eliminate this source of spread.

What can you do?  Perhaps the best way gardeners can participate is to help with education efforts.  If you spot a regulated species for sale while shopping at a nursery, farmer’s market or garden club event, please send a message to: or call Mindy Wilkinson, WDNR Invasive Species Coordinator at 608-266-6437.  The seller will be given information about the regulations specific to the unlawful species.  In most cases, the sellers simply are not aware of the new legal status of some plants.  According to Mindy, the cooperation that has been shown by plant enthusiasts, nursery owners and the public to help weed out regulated invasive plants marketed in Wisconsin has been very encouraging!

• Illustrated list of regulated plants
• Synonyms for regulated plants
• State Nursery Inspectors (map with phone numbers)


No welcome-wagon for this new neighbor:

Meet Japanese hedge parsley (Torilis japonica)

Here’s a relative newcomer to our area. It has been found in about 10 Wisconsin counties and is believed to be much more widespread in the state. You may have already spotted a population and confused it for another weedy species, such as wild chervil, caraway, poison hemlock, parsley or sweet cicely. Japanese hedge parsley differs from those species by its smaller leaves and more open-branched structure.  It can be controlled by pulling or mowing just before flowering.

Japanese hedge parsleyGlyphosate or triclopyr can knock it back when used early in the spring or upon re-sprouting after cutting.  Your first sighting of this species may be along a trail, where you might see a line of individual plants.  That’s because the tiny fruit on this invasive rascal has a Velcro-like hair that hooks onto humans or animals and then drops off elsewhere after hitching a ride.  It’s a problem because it will spread rapidly and crowd out native species in the understory of woodlands and savannas.

For more information visit: and/or:






Two new invaders found in Milwaukee County


The Milwaukee County Parks Natural Areas staff recently discovered small populations of two uncommon invasive plant species: lesser celandine (Ranunculus ficaria) and white-top (Cardia draba). Both are relatively new to Milwaukee County, which makes their correct identification and treatment important.

Two new invaders  1Lesser celandine is part of the buttercup family with a distinct yellow flower and shiny dark green leaves. It is a perennial, spring ephemeral that grows to approximately 4 to 12 inches in height. Growth characteristics are lateral through a cluster of tuberous roots, which form large mats in low open woods and floodplains. This particular patch was found in Lake Park which is located in the City of Milwaukee. There is a very narrow window when lesser celandine treatment is effective (early April to early May). A treatment of 2% Garlon 4 in bark oil is recommended to penetrate the waxy leaves. Manual control requires the removal of all bulblets and tubers. Be careful; the disturbance of the soil could invite other invasive species to colonize so manual removal is only appropriate on smaller infestations.Two new invaders  2

White-top, also known as hoary cress, belongs to the mustard family. It grows as a perennial forb with numerous white flowers giving the plant a flat-topped appearance. The species blooms from late April through June. If conditions are right, this aggressive plant will flower a second time and produce an additional crop of seeds later in the summer.

At maturity white-top can reach a height of two feet. This particular patch contained more than 300 stalks and was found in a disturbed area near State Highway 45, adjacent to the park-and-ride on the north side of Watertown Plank Road. Control of white-top is most successful when using a 2% treatment of Roundup. Hand pulling or digging is only useful on small infestations and requires complete removal of the plant every 2-4 years.

If you discover populations of lesser celandine or white-top in southeastern Wisconsin this season, please report the locations to the Wisconsin Department of Natural Resources at:



Citizen scientists wanted! Join the 2012 Roadside Invasive Species Survey

2012 Roadside Invasive Species Survey  1Join more than 150 volunteers this summer to map wild parsnip (Pastinaca sativa) along our southeastern Wisconsin roadways.

Wild parsnip is a tall perennial plant (up to 5 feet) that spreads quickly and is especially successful in taking over degraded habitats found along roadsides. The species has been steadily increasing its range throughout Wisconsin and is becoming common in ditches, roadsides, and along agricultural fields.

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2012 Roadside Invasive Species Survey  3Wild parsnip not only displaces our native species, but also threatens human well-being by causing phytophotodermatitis. If the plant juices come in contact with skin in the presence of sunlight, a rash and/or blistering can occur as well as skin discoloration that may last for months. Care should be taken to avoid direct skin contact with the juices of this plant. Proper clothing (gloves and a long-sleeved shirt) must be worn to prevent the phytophotodermatitic effects.

Volunteer surveyors are still needed for Sheboygan and Washington Counties. If you live, work and or play in these counties, you and a friend can take an active role in controlling this dangerous plant.

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And, the survey is just plain fun! To volunteer or for more information about the survey, please contact us at: and visit our website:




Our SEWISC 2011 Roadside Survey information goes national – check it out!

EDDMapS is a web-based mapping system for documenting invasive species distribution. Launched in 2005 by the Center for Invasive Species and Ecosystem Health at the University of Georgia, the goal is to maximize the effectiveness and accessibility of the immense number of invasive species observations recorded each year.

↓ Click on image to see 2011 SEWISC records of teasel in Mequon, Ozaukee County

SEWISC 2011 Roadside 1As of May 2012, EDDMapS has over 1.8 million records, and more than 2,000 of those records were collected by residents of southeastern Wisconsin during the 2011 SEWISC Invasive Species Roadside Survey.

EDDMapS combines data from other databases, organizations such as SEWISC, and from individual volunteer observations to create a national network of invasive species distribution data that is shared with educators, land managers, conservation biologists, and beyond.

Along with our 2011 distribution data for giant reed grass, teasel and Japanese knotweed, SEWISC's 2012 wild parsnip records will also be added to the database later this year. Visit the national database at:



Wisconsin’s seventh annual Invasive Species Awareness Month throughout June, 2012

"Slow the Spread by Boat and Tread"

In 2005 Governor James Doyle demonstrated a firm commitment to address the issue of invasive species in Wisconsin by creating the Wisconsin Council on Invasive Species and by declaring June of that year the first annual Invasive Species Awareness Month. For each of the past 7 years, that tradition has continued in an effort to raise awareness about non-native invasive plants and animals.

Click on image ↓


Grand Prize poster 2
Grand Prize poster design by SEWISC Region resident,
Clara Montes Grade 5, Kohler Elementary School, Sheboygan County

During Invasive Species Awareness Month, numerous field trips, workshops, presentations and work parties will be held throughout the state. The goal is to create a statewide alliance of non-profit conservation groups, land trusts, Native American agencies, educational institutions, botanical gardens, nature centers, forest industry groups, green industry groups, and county, state and federal agencies, who will work together to inundate Wisconsin citizens with the message "Invasive species is an important issue to confront!"

Each year the Council recognizes the efforts of outstanding individuals and organizations that have demonstrated exemplary work in combating the spread of invasive species. We are proud to report that SEWISC volunteers Martha Lunz, John Lunz and Eric Tarman-Ramcheck along with SEWISC Board of Directors Vice President, Jerry Ziegler each received a 2012 Invader Crusader Award for their dedicated work in southeastern Wisconsin!

This year, 4th and 5th grade students across our beautiful state had the opportunity to participate in a poster contest sponsored by the Council and the Wisconsin Department of Natural Resources. The goal of the contest was to increase awareness of shoreline and wetland invasive species and to teach people how to prevent the spread of invasive species in these habitats.


ISAM 2012 Awardees
Paul Schumacher, Chair of the Wisconsin Invasive Species Council (left) and James Reinartz, Council member and Treasurer of SEWISC Board of Directors (right) celebrate with 2012 ISAM Award Winners Jerry Ziegler (Professional Individual – Nonprofit), Martha and John Lunz (Volunteer Pair), and Eric Tarman-Ramcheck (Volunteer Individual) at the Olbrich Botanical Gardens in Madison.



Hmmmm….which invasives should I treat over the summer months? Here’s a suggestion

Beginning with this issue, we will routinely highlight one or more species that can be successfully treated during the season of each SEWISC e-newsletter release. More resources for controlling these and other invasive populations can be found on our website:

Common and cut-leaved Teasels (Dipsacus fullonum and D. laciniatus)

Hmmmm  1Common and cut-leaved teasels are monocarpic perennials native to Europe, introduced to North America in the 1700s. Teasel prefers to grow in open, sunny habitats and is commonly found in more disturbed areas such as roadside ditches. Teasel grows as a basal rosette the first year or two and sends up a flowering stalk thereafter. Both common and cut-leaved teasel have large taproots, making this species difficult to eradicate.

Hmmmm  2Cut-leaved teasel generally has white flowers and blooms July through September, while common teasel blooms June through October and typically displays purple flowers. The flowers of both cut-leaved and common teasel are arranged in dense oval-shaped heads. The stalks sometimes reach 6-7 feet in height. Teasel has opposite, oblong leaves, which are prickly along the midrib, and form cups that hold water where they meet the stem. Chemical control is the most efficient way to control this species. A 2% glyphosate mixture has been found to be quite effective when applied directly to the foliage and stems before flowering occurs. After teasel is in flower, cutting the plant just below the ground surface will kill it. If seed set has already begun when the plant is cut, the seed heads should be cut and bagged to prevent further spread.

Japanese Knotweed (Fallopia japonica)

Hmmmm  3Japanese knotweed is a 5-10 foot tall flowering perennial introduced to North America in the late 1800s. This invasive species can thrive in a variety of habitats, soil types, and moisture conditions with a tendency to grow in wetlands and along riverbanks. The stems of Japanese knotweed are hollow, bamboo-like in nature, and typically green with reddish speckles. Japanese knotweed typically spreads by extensive networks of underground rhizomes, which can reach up to 6 feet in depth and 60 feet in length. The blooming period for the cream-colored clusters of tiny flowers is typically June through August. Japanese knotweed should be cut after spring leaf out and a mixture of 5% glyphosate applied on re-sprouts April through August. It is very difficult to control and a single treatment is seldom, if ever, effective so plan on making repeated applications.