Invasive Species Control

Effective vegetation removal techniques

Herbicide application

Works for large sites or sites with little or no native vegetation. Selective use of herbicide is especially effective for aggressive non-natives. The number of treatments depends upon site conditions, species present, and the presence of a seed bank within the soil. Repeat applications may be required for persistent perennial weeds.

Smothering

Works for smaller sites when chemical use is not desirable. Landscaping fabric, dense compost, or grass clippings cover existing vegetation and is left in place for a full growing season.

Cultivation

Involves tilling an area regularly from spring to fall, to between four to five inches deep, to destroy weed root systems. Because it can also bring up weed seeds, cultivation needs to occur at regular intervals, between two to three weeks, to ensure undesirable perennials do not re-sprout. This has the highest risk of soil loss from erosion. Plants with deep root systems may need supplemental herbicide application.

Prescribed burning

Can be used to prepare a site, but it is most commonly used to maintain a prairie landscape. See the section on maintenance for more information on prescribed burning.

Stabilize erodible areas

Many native plant installations are located along streambanks, shorelines, and other sloped areas that have a tendency to erode. Before planting occurs on these sites, the surrounding soils need to be stabilized. Structures such as silt fences, erosion control blankets, straw mulch, and straw bale dams can be installed to control erosion and siltation. As a site becomes stable, seeding with permanent native species helps with optimal long-term erosion control. Cardno provides various bioengineering materials for erosion control.

Prepare planting and seedbeds

To prepare the soil and create optimal plant conditions, before disturbing any ground:

  • Check for any buried utilities
  • Clear area of debris that would interfere with planting
  • Mow any excess existing vegetation growth
  • Apply broad-spectrum or targeted herbicide, depending on species present
  • De-compact any areas of special concern
    • Lightly de-compact tilled or loose soil with a roller, cultipacker, or similar equipment. If using a no-till seed drill, tilling can usually be omitted.
    • If ground is wet, tilling should not occur until the soil dries enough to break apart when tilled.

Amend soils

For stormwater applications like rain gardens and bioswales, soil can be amended to create appropriate growing conditions for wetland plants and allow for drainage required to allow these features to function properly. These areas often have the native soil removed and have a combination of compost and sand applied to achieve this objective.

For a complete guide, please download our Installation and Maintenance Guidelines PDF document.