Robert W. Freckmann Herbarium
University of Wisconsin - Stevens Point

Vascular Plants

Plants of Wisconsin


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Wisconsin's Potentially New Invasive Plants

The Wisconsin Department of Natural Resources and the Wisconsin State Herbarium have announced a new initiative.
Wisconsin Invasive Plants Reporting and Prevention Project
Prevent the spread of plants known to be newly invasive in Wisconsin or in nearby states.
Identify these population and control or destroy them before they can spread.
We hope the information presented here will assist in this effort.

Collecting & Reporting Guidelines

Invasive Plants of the Future

image of common teasel    

Invasives Home
Invasive Plants Targeted
Aquatic / Wetland
You Can Help
Collecting & Reporting Guidelines
Invasive Plant Report Form (pdf -Adobe® Reader®)

The following information has been supplied by the Wisconsin Dept. of Natural Resources to aid in this project.

When You Find a Suspected Target Plant   --- Here's what to do:

1. Collect Specimens or Take Pictures  (See Reporting Instructions below)
        (For plant experts, it may be enough to simply report the plant and its location. Please contact project staff.)

  A. Collect, press and dry a complete sample.  See website instructions for making and using a plant press.  This method is best because a plant expert can examine the specimen (which might end up in a state herbarium, with your name listed as collector).
    Or --
  B. Collect a fresh sample and mail right away.  Enclose in a plastic bag with a moist paper towel. 
    Or --
  C. Take detailed photos -- digital or film – and mail or email them. 
Regardless of method used, provide as much evidence as possible.  Try to include flowers, seeds or fruit, buds, full leaves, stems roots and other distinctive features.  In photos, place a coin, pencil, ruler or hand for scale.  If you can send a specimen and take photo, all the better. 

2. Note Location

   (Provide one or more of the following)
  -- Latitude & Longitude
  -- UTM (Universal Transverse Mercator) coordinates
  -- County, Township, Range, Section, Part-section
  -- Precise written site description, noting nearest city & road names, landmarks, local topography 

If possible, give the exact geographic location using a GPS (global positioning system) unit, topographic map, or the Wisconsin Gazetteer map book and Town Range Section Quarter.  If using a map, include a photocopy with a dot showing the spot.  On the Internet, you can use to find the precise location on a digital topographic map.  Click the cursor on the exact collection site and note the coordinates (choose UTM or Latitude/Longitude).  

3. Send Specimen (or Photo) & Reporting Form

Use the REPORTING FORM (pdf -Adobe® Reader®) on this website or create your own.  Please provide this essential data:
  -- Collection date & county
  -- Your name, address, phone, email
  -- Exact location (Latitude/Longitude or UTM preferred, AND Township/Range/Section)
  -- Plant name (common or scientific, best guess upon collecting)
  -- Land ownership (if known)
  -- Population description (estimate number of plants, area covered)
  -- Habitat type(s) where found (forest, field, prairie, wetland, open water)

Mail specimen (or photo) with its data form to: 
   Invasive Plants Project, UW Herbarium, 430 Lincoln Dr., Madison, WI 53706

4. Help Control the Population

Once these invaders are found and reported, containment and eradication is next.  For some plants -- and depending on the time of year – control efforts will be needed immediately.  See the control information provided for each species.  In general, any hand-pulling, mowing or chemical treatment strategy should be timed or designed to prevent seed development and further plant dispersal.   

NOTE  –  Even if you are unable to attempt any control work, it is still important to let us know about ALL target plant discoveries – especially the species that have not been documented in Wisconsin or have limited ranges.  We need to know where the invaders are – so we find someone to contain them and monitor the site over several years.      

Reporting Instructions 

Check photos, descriptions on this website or use the Wisconsin Plants Identification Guides to help narrow the possibilities for plant identity.  Be sure to include notes about site location & description, population size and control actions taken.   

Print out (or copy to a word-processing document) and complete the Invasive Plant Report form (pdf -Adobe® Reader®)-- to report occurrences of suspected target invasive plants growing in Wisconsin or near state borders. (See Target Plant List )  Please use one form for each sample.   

Enclose form with your ID Evidence: photographs, pressed plant specimens, or fresh specimens. (guidelines on each method.)   

Send to the Wisconsin State Herbarium.   (Use address on form.)  Botanists will confirm each plant's identity and will tell you the name via email, letter or phone.  

"ID REQUIRED"    --- Evidence-Collecting Guidelines 

Most of the 15 Target Plants have look-alikes (both native and non-native) which can make identity uncertain, especially before flowering.  At least one form of evidence will be required to establish plant identity.  Use the following as a guide to the evidence preferred.   


Photographs.  Use either film or digital camera, and try to capture maximum details.  Focus on flowers, leaf shape, leaf & stem arrangement, fruits, For a size scale, be sure to include a pencil, dollar bill, coin, human hand or other familiar object.  For giant hogweed, have a person stand near (but not touching) the plant.  Send by email or US mail (address below).   

Fresh Specimens.   Diagnostic samples of the plant – especially flowers, fruits, stem section with leaves, or whole plants – can be sent by US mail.  Package with a moist paper towel in a sealed plastic bag.  Keep cool until mailing and send ASAP.   

Pressed & Dried Specimens. To make pressed specimens, see Voucher-Making instructions.  If you have a plant press or can make one, press plants providing as many details as possible.  Enclose the specimens – each in a newspaper sleeve -- between two stiff cardboard sheets and send by US mail.   

Evidence Requirements / Preferences for specific target plants 

1. Photos OK  (try to take several, with a coin, pencil or hand included for scale)
   -- Giant hogweed  (leaves, stem closeup)
   -- Japanese hops  (leaves, leaves with twining stems)
   -- Water chestnut  (floating rosette)
   -- Flowering rush  (when in flower)
   -- Teasel [both species]  (flower heads, stem & leaf nodes, leaf undersides closeup)
   -- Frog-bit  (when in flower)
   -- Swallow-wort [both species]  (show flowers, or twining stems with pods)
2. Specimen preferred
   -- Hedge-parsley [both species]  (flower umbels, stem with leaves)
   -- Wineberry  (stem tops, especially new growth with prickly hairs),
   -- Swallow-wort  (flowers, leaves & vines)

3. Specimen required:
   -- Hydrilla  (leafy stems, fresh or dried)
   -- Stilt-grass  (leaves with stem, flower spikes) 
   -- Flowering rush (if leaves only)
4. BOTH photo and specimen.
   -- For all plants: Having both forms of evidence is best, if possible.   

Note:  If you don't have a specimen or photo, but know the location of a target plant, fill out and send the Reporting Form (pdf -Adobe® Reader®) and contact the coordinator.   

Use the Voucher-Making Instructions for guidance on making and using a plant press.  

Remember to include a completed Reporting Form (pdf -Adobe® Reader®) with each specimen.  Send to:

   Invasive Plants Project, UW Herbarium
   430 Lincoln Dr.,  Madison, WI 53706

Vascular Plants

Plants of Wisconsin


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