Weedy Update

This page will show pictures of plants that have been identified by Lincoln County UW-Extension Office.  If available, University Bulletins will accompany the pictures to provide more information regarding the plants.


Common Buckthorn

(Rhamnus cathartica)

Common Buckthorn 002

This plant is invasive. If found it is necessary to remove as soon as possible. It invades oak forests, riparian woods, savannas, prairies, old fields, road sides, and thrives in well drained soil. It can tolerate many environmental conditions and leaves out very early and retains leaves late into the season, longer then other vegetation. It is an allelopathic plant, this means it produces a chemical that stops the growth of over vegetation that may be trying to grow around it.  For control, small plants may be pulled. For larger plants you can girdle the tree by exposing the inner hardwood at a minimum of six inches, this can be done any time of the year. There are other options such as cut it down to a stump and treat it with glyphosate. Above is a picture of Common Buckthorn that was brought in. If you are not sure if what you have is common buckthorn you can bring it in to the office to be identified.


(Genus Hieraclum)

Hawkweed (genus Hieraclum)

Shown above is Hawkweed that was brought into the extension office. Hawkweed is most easily identifiable by it’s flower but before it starts to flower it can be harder to detect what type of weed it is. It can be fairly aggressive and take over lawns and gardens if not managed properly. Some of the better ways of managing the weed at this time is to apply herbicide. This is a problem for organic growers though. There are some preventative actions you can take such as mulching, to decrease the likely hood of the weed being a problem, or in some cases a vinegar spray has been helpful in killing off weeds. However it may not get the roots and the plant will come back. That is why it is important that you are being preventative. You are mulching your garden beds, fertilizing in the fall and watching for problem areas where there could be the potential for new weeds to grow.

Prostrate Knotweed

Prostrate Knotweed

(Polygonum arenastrum)

      Shown above is the Prostrate Knotweed. It is the earliest germinating of all the summer annual weeds. It favors compacted soil and will take over quite quickly before desirable grasses can grow. They will grow in moist light soil, but will do well in salty, infertile, hard soils that other plants can’t tolerate. You will notice them near walkways and driveway and where heavy foot traffic through the yard is. They are drought tolerant and produce chemical that will inhibit the growth of other plants. 2,4-D is a herbicide that will help after the plant has emerged. Some preventative planning such as aerating the lawn can help prevent the growth of Knotweed. The best time to aerate your lawn is between August 20th and September 15th.

Night shade

Common Nightshade (Deadly Nightshade)

( Solanaceae)

Pictured above is Common Nightshade or sometimes referred to as Deadly Nightshade. It prefers moist soil in full sun, but will tolerate dry to flooded conditions and some shade.  It is widely spread by birds when they consume the berries. It is a poisonous plant if it is  ingested by humans, livestock and poultry. The berries are edible to some wild birds. It is considered a noxious weed in the state of Wisconsin. It can be controlled through tilling. Small amounts of nightshade can be removed by digging or hand pulling the plant. If it’s not possible to remove by hand, mowing over it several times in a growing season may keep it in check. A chemical control that can be used is 2, 4-D, dicamba, or cutting it down and apply glyphosate are some options for controlling of nightshade. With all herbicides read the label for the safest and beneficial way of using it.  If it happens to be growing near a water source make sure to isolate where you are spraying because you may contaminate the water source.

Wild Grape Vine

Wild Grape Vine

(Vitus riparia)

The plant  pictured above is common and can be found in most forests. It can be considered an obnoxious plant if you don’t want it there. It’s fruit is edible and it likes well drained soil but can survive in drier conditions. It can climb up the trunks of trees making it harder to  find fruit/leaves to identify if it is wild grape. If you do want to get rid of it because it may be crowding more desirable plants, you can cut it down to stump and apply glysophate to the stump. This is best applied late August – September. With any chemical application it is important to read labels and are following all safety precautions.