Managing Invasive Plants

Maplewood's Approach

Maplewood addresses invasive plant problems on several fronts:
  • Early Detection and Rapid Response. Maplewood’s priority for invasive plants is to find new, incoming species (early detection) and to quickly eradicate them while patches are still small (rapid response). This method has had the most success and is less expensive than trying to remove species that are widespread. In 2011, Maplewood partnered with RCCWMA (see below) to develop a pilot program for an early detection program for volunteers - the Invasive Plant Patrol. This group of citizen monitors looks for new invasives at parks and natural areas and reports them.
  • Manage widespread species. Some invasive plants, such as garlic mustard and buckthorn are already common in our area. Because they are widespread, it is not feasible to eradicate all patches of these. On city land, Maplewood prioritizes management of common invasive plants based on ecological quality of site, size of infestation, and other factors.
  • Support for residents. The city helps support homeowners’ efforts to manage invasive plants through education, demonstrations, and other programs. The Maplewood Buckthorn Program, for example, provides curb-side pick-up on a specified day each year for residents that remove buckthorn on their site (see link below for more information).
  • Partnerships:
    • Maplewood is one of the founding partners of the Ramsey County Cooperative Weed Management Area (RCCWMA). Cooperative Weed Management Areas are local level organizations that enlist agencies, businesses and citizens to work together to combat invasive plants. RCCWMA’s priority is Early Detection and Rapid Response. Partners map new invasions, notify and educate land owners of species on their properties, share resources and knowledge, help educate and train citizens and staff and offer assistance to residents and businesses.
    • Maplewood has partnered with Century College Biology classes for several years. Students have helped clear buckthorn from large areas and remove small patches of garlic mustard, wild parsnip and Oriental bittersweet.
    • The city also has partnered with local businesses for buckthorn herbicide savings for our residents.

Management Methods

Many methods are used to manage invasive plants and management strategies differ for each species. Using multiple methods - integrated pest management - is usually is more successful than using a single method. The best methods to use depend on the species present, size of the infestation, site conditions, local regulation and time of year.
  • Mechanical control methods. This includes prescribed burns, pulling, digging, mowing, cutting and removing seed heads.
  • Chemical control using herbicides. The type of herbicide, time of year to apply and application method is tailored to the species being managed, proximity to water, soil type and presence of nearby native plants.
  • Biological controls. Biological controls are living organisms which normally control plants in their country of origin, but did not come with the plant when it was brought to Minnesota. For example, several insects feed on purple loosestrife in Europe where it is native. These insects were not brought with loosestrife when it came to the U.S. The United States Department of Agriculture thoroughly tests biological controls to determine any adverse effect to native species. These organisms must only attack the target invasive species or they are not approved for use. Organisms may be insects, bacteria, fungi or viruses.
When determining what methods to use, we consider what’s most effective for a species and the particular situation as well as the environmental, ecological, and economic impacts of the treatment.

Maplewood usually uses multiple methods to manage invasive species on a public site. For example, spotted knapweed is a concern at some of our Neighborhood Preserves. We have pulled and dug plants, conducted prescribed burns, mowed prior to flowering and released two species of biocontrol beetles. Once beetle populations increase, we will be able to move them to additional areas with knapweed problems.

Documents & Links