Managing Non-native Plant Species

A landscape photo with green ground cover, which looks lush, but is entirely a type of invasive species grass.
Japanese stiltgrass is an aggressive invader of forest lands throughout the eastern U.S. Infestations can impact the diversity of native species, reduce wildlife habitat, and disrupt important ecosystem functions [USDA].

NPS Photo.

The process of controlling non-native plants, especially locations that exhibit well-established populations, can be very challenging. Non-native plants can be found in large patches by themselves or found mixed within patches of native plants. Some of these non-native patches can be completely removed if the species is treated when the outbreak is still small. Others non-native species are so common and in such huge quantities, that simply managing what’s there to stop them from spreading, is the primary goal. Two methods exist for managing invasive species: mechanical and/or chemical treatment.

Mechanical treatment:
This treatment involves physically pulling or cutting the invasive plant. This method is the preferred method when it is possible, typically with smaller patches of non-native species. However, sometimes this method can stimulate new growth which then requires a more aggressive method of control.

Chemical treatments:
This treatment is more aggressive than mechanical treatment, and involves targeted spraying of chemicals, called herbicides, on highly infested non-native areas of the park.
 
A small cluster of white flowers, each with five, delicate-looking, heart-shaped petals.
As an invasive species here at First State NHP, native to eastern Asia, Multiflora rose forms dense thickets that invade pastures and crowd out native species.

NPS photo.

How You Can Help To Prevent the Spread of Non-native Plants:
The main way non-native plant species spread is through human activities, usually unintentionally. Here are six ways you can prevent the spread of invasive plant species:
  1. Clean your outdoor gear after each use, including but not limited to, shoes, clothing, backpacks and/or camping gear, boats and other water recreation items.
  2. Only collect and use firewood from the immediate area you are wishing to make a fire. Similarly, do not transport firewood or deadwood to far, new areas, because seeds can travel with that wood.
  3. Volunteer for events that help maintain native plant species.
  4. Select and plant native plants in your garden, rather than “pretty” non-native species.
  5. Learn about and be aware of the invasive species within your area, so you can identify them.
  6. Check your pet’s paws when traveling with them.

Last updated: June 26, 2020

Contact Info

Mailing Address:

First State National Historical Park
10 Market Street
New Castle, DE 19720

Phone:

302-317-3854
To speak to a park ranger, call the park Welcome Center (302-317-3854) and someone will return your call as soon as possible. For a more immediate response, please email the park at firststate@nps.gov.

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