Our maintenance crew works tirelessly hand pulling, weed whipping, and spraying weeds all season long to keep undesirable plants in native restorations under control. But are there some weeds that are worse than others and should take priority?  You might have heard of the word noxious being used when referring to certain weeds, but what does that really mean? Then, once you know what the noxious weeds are, how do you keep them from spreading?  

Noxious weeds are designated by the Minnesota State Department of Agriculture as a plant that has the potential to be harmful to humans, animals, crops, livestock, property, transportation, or the environment. For example, Poison Ivy is a noxious weed because it gives people who come in contact with it a rash. Another example is Garlic Mustard and Spotted Knapweed which both produce chemicals that change the soil and make it less habitable for native bugs and plants. Leafy Spurge is on the list because it is toxic to livestock. Efforts must be done to control the spread, dispersal, and maturation of propagating parts of plants found on the noxious control list. Here are some examples of weeds we see often and take priority in controlling because they are found on that list:  Canada Thistle, Garlic Mustard, Leafy Spurge, Purple Loosestrife, Spotted Knapweed, Common and Glossy Buckthorn, and Poison Ivy.

A dense Purple Loosestrife stand that chokes out rare or endangered wetland plants and creates habitat unsuitable for native wildlife

How does one stop the spread, dispersal, or maturation of propagating parts? There are several methods we use at Natural Shore Technologies, including both chemical and mechanical means of control. Because just one of these plants can potentially produce thousands of seeds in a year, preventing the plant from going to seed is the first goal. We do this by spraying the plant early with specific herbicides depending on the plant and site conditions. For example, we use a special type of herbicide safe for spraying near water. We also use another herbicide that will only kill plants with leaves and not harm native grasses. Another method of control involving herbicide is using a special concentration of chemical to spray on a cut stump of a noxious weed. Buckthorn and Purple Loosestrife are common victims of this method. 

Spraying Poison Ivy with a broadleaf specific herbicide.

Purple Loosestrife that has been cut at the base and sprayed with herbicide