Weed Identification

Noxious Weeds?

In past newsletters, invasive plants have been highlighted. But there is a subset of these plants called “noxious weeds.” What is the difference? An invasive plant is any plant that tends to multiply quickly and crowd out other species. There are both native and alien invasive plants. A noxious weed is one of only three plant species named specifically in Wisconsin statutes as requiring control. These are Canada thistle (Cirsium arvense), field bindweed (Convolvulus arvensis) and leafy spurge (Euphorbia esula).

Section 66.0407 states “A person owning, occupying or controlling land shall destroy all noxious weeds on the land,” and “The chairperson of each town . . . may annually on or before May 15 publish a class 2 notice, under chapter 985, that every person is required by law to destroy all noxious weeds, as defined in this section, on lands in the municipality which the person owns, occupies or controls.” The town chairperson also has the right to appoint one or more Weed Commissioners, whose duties are to enforce the statute. A weed commissioner investigates reports of noxious weeds, informs landowners of the requirement to destroy these weeds, or if the landowner does not comply, the weed commissioner causes the weeds to be destroyed. Landowners are billed for the removal on their property taxes.

In addition to noxious weeds, there are two “nuisance weeds” named in Wisconsin statue 23.235: purple loosestrife (Lythrum) and multiflora rose (Rosa multiflora). For these plants “no person may sell, offer for sale, distribute, plant or cultivate any nuisance weed or seeds thereof. Violators are fined up to $100 per offence.
– Christine Molling July, 2009

For more detailed information about invasive plants: http://dnr.wi.gov/topic/Invasives/


Every person is required by law to destroy all of the following noxious weeds growing on land in the Town of Berry, owned, operated, or controlled by that person:

Canada thistle
Leafy spurge
Field bindweed (Creeping Jenny)


Other Invasive Plants

Buckthorn and Eurasian Honeysuckle(1st two are same article)
Dames Rocket
Garlic Mustard
Purple Loosestrife
Spotted Knapweed
Wild Parsnip


Canada Thistle

photo of Canada Thistle


For information about controlling thistle, see: Canada Thistle Fact Sheet - Wisconsin DNR







Leafy Spurge

Leafy Spurge - Photo: WDNR

Leafy Spurge

For information on control techniques, visit the Leafy spurge factsheet by University of Wisconsin-Extension.










Field Bindweed

Field Bindweed

Field bindweed is difficult to eradicate because the seeds remain viable in soil for up to 20 years. One plant can produce up to 500 seeds. The deep, extensive root system stores carbohydrates and proteins and allows it to sprout repeatedly from fragments and rhizomes following removal of aboveground growth.

For information about control techniques see theField Bindweed Fact Sheet USDA Forest Service






Buckthorn and Eurasian Honeysuckle

Pictures of Honeysuckel and Buckthorn berrys

Honeysuckle (left) and buckthorn (right). Photo: C. Molling

Two of the more pernicious invasive trees and shrubs in our area are Eurasian honeysuckle and buckthorn. Both of these non-native species crowd out native plants by leafing out early, losing leaves late, and having berries that birds eat, dispersing seeds in their droppings.

     Eurasian honeysuckles (several species) are multiple stemmed shrubs with oblong, paired leaflets along somewhat delicate arching branches. They bear white through pink fragrant flowers in spring, and yellow, orange or red ¼” berries in late summer.

Buckthorns (two species) are small to medium shrubs or trees, with dark green oval-elliptical leaves. Buckthorns are easily identified in fall by their shiny black ¼” berries.

     Fall is an ideal time to remove these invasives because their showy fruits and their tendency to keep their leaves late make identification easy. Also in fall, the plants draw nutrients back down from their leaves.

Control and treatment methods can be found at http://dnr.wi.gov/topic/invasives/fact/commonbuckthorn.html for common buckthorn and at http://dnr.wi.gov/topic/invasives/fact/amurhoneysuckle.html for Honeysuckle.

–Christine Molling, WI DNR Sept, 2009




Dames Rocket

Pretty Invasive

Photo: C. Molling

Have you seen all those pretty pink flowers blooming along the roadside in June? I always thought they were phlox. I was wrong! These flowers are an alien invader called dame’s rocket (Hesperis matronalis). These Eurasian members of the mustard family are spreading in Wisconsin’s woodlands and fields due to their prolific seed production. They spend their first year as a rosette of leaves and send up a 2-4 ft flower stalk in their 2nd or 3rd year. It’s easy to tell the difference between dame’s rocket and phlox. Dame’s rocket has 4-petaled flowers and alternating toothed leaves, while phlox had 5-petaled flowers and opposite smooth leaves.

For information about removing and controlling Dame's Rocket, see: http://dnr.wi.gov/topic/invasives/fact/damesrocket.html

UW Extension, Christine Molling June, 2009




Garlic Mustard


photo of Garlic Mustard

The beauty of the Town of Berry and surrounding areas are being threatened by a European species of plant that is rapidly spreading in Wisconsin.

Now (Spring) is the time to stop it! This plant can consume woodlands in 1-3 years. It shades out the native wildflowers and eventually kills them. Devil’s Lake State Park and the Baraboo Bluffs are covered with it. There are three patches on my land here in the Town of Berry. This is the best time to wipe it out before it gets to the flowering and seed producing stage.

Walk your land and look for large patches of small green plants that are present in early April before most plants are green. Crush a leaf and if it smells like garlic it is garlic mustard Alliaria petiolata.

The plant is a biennial. It will flower the second year. First-year plants appear as a rosette of rounded/kidney shaped green leaves close to the ground. Rosettes remain green through the winter and develop into mature flowering plants the following spring. Flowering plants of garlic mustard reach from 2 to 3-1/2 feet in height and produce buttonlike clusters of small white flowers, each with four petals in the shape of a cross.

My patches are in the first year and I will use a herbicide like Roundup to eliminate them. This may be used in spring or fall. If the stalk elongates and flower buds appear it is best to hand pull and bag them so the seeds do not spread. Prevent any plants from going to seed.

If you do find garlic mustard make sure to look outside the patch for loner plants. I even have one in my flower bed!

More information about controlling garlic mustard can be found at: http://dnr.wi.gov/topic/invasives/fact/garlicmustard.html.

-Mary Bauschelt May 2005 Newsletter




Purple Loosestrife

photo of purple loosestrife

(Lythrum salicaria, L. virgatum, and their hybrids)
Purple Loosestrife displaces native wetland vegetation, degrades wildlife habitat, displaces rare plants and animals, and chokes waterways. Prevention is the best way to stop purple loosestrife invasion. The following steps are recommended by the Department of Natural Resources (DNR):

  • Be on the lookout for pioneering plants or isolated small colonies and remove them immediately.
  • Rinse off equipment, boats and trailers, clothing, and footwear used in infested areas before moving into uninfested areas.
  • Remove and destroy purple loosestrife planted in lawns and gardens. It is illegal to cultivate purple loosestrife in Wisconsin.

For more information about purple loosestrife or control methods, contact the Purple Loosestrife Bio-Control Program at Brock.Woods@dnr.state.wi.us or WDNR Research Center at 221-6349 and visit the Wisconsin DNR Purple Loosestrife Fact Sheet

-Submitted by Mary Bauschelt August 2005 Newsletter




Spotted Knapweed

photo of spotted knapweed

Photo courtesy of the Nature Conservancy

Spotted knapweed (Centaurea maculosa) is a shrubby, wiry plant, whose narrow leaves and stems have a grayish blue color. The pink to purple 3/4 inch blooms resemble a soft thistle, with darker tipped comb-like fringes. The plant is often found along roadsides, railroad tracks, and parking lots, but is increasingly found in all sunny natural areas.

For more information about controlling spotted knapweed, visit the DNR website at http://dnr.wi.gov/topic/invasives/fact/spottedknapweed.html






photo of Teasel plant and pod

A relatively new plant invader to Wisconsin is teasel. Teasel is an aggressive exotic that chokes out native plants.

Common teasel (Dipsacus fullonum subsp. sylvestris) and cut-leaved teasel (Dipsacus laciniatus) were originally introduced from Europe for their pincushion-like seedheads. The seedheads were mounted on frames and stroked against wool cloth to raise the nap, creating a smooth, soft surface. Today, florists use the dried seedheads in decorative displays.

You will recognize teasels by the 2-7 foot dried stalks with spiny, egg-shaped seedheads from the previous year mingled among this year’s green plants. First year plants form a basal rosette of leaves. Older plants form prickly stalks, with paired prickly leaves joined at their bases along the stalk, forming a cup. Do not confuse the native cup-plant with teasel – cup-plant has leaves without prickles and has a relatively smooth stem. Teasels bloom with hundreds of tiny white to lavender florets on each bud.

For information on how to control common teasel, visit the DNR website:http://dnr.wi.gov/topic/invasives/fact/commonteasel.html.

-Christine Molling, WI DNR July, 2008




Wild Parsnip

photo of wild parsnip

Wild parsnip (Pastinaca sativa) can be confused with prairie parsley (Polytaenia nuttallii), a native prairie species listed as threatened in Wisconsin. Its flowers and leaves resemble those of wild parsnip. Comparatively, flowers of the prairie parsley plant are light-yellow, sparse, and typically found at the end of the stem. The leaves are pinnately compound like those of the wild parsnip, but are oblong with few teeth.
The plant has a long, thick taproot, which is edible. Flowering plants produce a single, thick stem that contains hundreds of yellow umbellate flowers. The lateral flowers often overtop the terminal flowers. Depending on the habitat and growing conditions, individual flowering plants range to over four feet in height.
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 several months.
Wild parsnip slowly invades an area in waves following initial infestation. Once the population builds, it spreads rapidly. This species is an aggressive, Eurasian weed that frequently invades and modifies a variety of open habitats.

Controling Wild Parsnip --CAUTION: Care should be taken to avoid skin contact with the juices of this plant. Proper clothing (gloves and a long-sleeved shirt) must be worn to prevent the phytophotodermatitic effects.

For more Information on wild parsnip and how to control and safely remove it, see: http://dnr.wi.gov/topic/invasives/fact/wildparsnip.html

-Mary Bauschelt June 2005 Newsletter