Invasive plants are naturally aggressive species that by mistake or through misguided human action are allowed to spread beyond their natural range. These species colonize areas where they are not native and degrade natural ecosystems. They reduce native biodiversity, impact agricultural ecosystems economically, destabilize existing trees, alter soil moisture, have deleterious effects on human health, and damage critical infrastructure. In addition to the damage they cause, invasive species do not perform the same ecological function as native plants in supporting co-evolved wildlife. Benefits of controlling invasive plants include protecting existing tree canopies, increasing native biodiversity, and saving on long-term maintenance costs.

When strategies are in place, personnel can maintain a high-quality landscape. Controlling and managing invasive species through sustainable and low-impact means represents an opportunity for eco-friendly action.

In order to successfully manage invasive plants, consider the following actions:

• Identify invasive species by consulting with local experts, referring to published information, or using online resources to learn the plant’s methods of reproduction and lifecycle (e.g., annual or perennial; broadleaf or grass; woody or herbaceous; cool season or warm season grower, etc.), and how to effectively target, control, and manage the problem.
• Consult a list of invasive species in the local area—in particular, regulated species that are illegal to import.
• Consult experts to develop individualized strategies to eradicate or at least control an invasive species. Experts may include local land managers or ecologists familiar with removal techniques, facility landscape architecture staff familiar with the region, or experts from another region with a similar climate.
• Determine whether site has adequate resources to completely eradicate the problem. Invasive species often thrive on disturbance, so partial or ineffective removal efforts can be worse than doing nothing at all. Some invasive species are best managed in place or contained, rather than partially eliminated.
• Minimize disturbance of existing soils and vegetation. Recently disturbed soils activate dormant seeds and encourage fast-establishing invasive species.
• Focus on eradicating new or young invasions before they become an established population.
• Excessively fertile soil is problematic because it increases competition, encourages fast-establishing species such as invasive plants, and can decrease the lifespan of many desirable native species that are adapted to leaner conditions. Keep organic matter content to less than five percent for all soils, and select species that have evolved with the existing native soils.
• Select a removal technique most appropriate for the target plant, and the budget. Effective techniques include smothering, spraying, hand weeding, brush hogging, string trimming, controlled burning, or seeding of desirable plants. Target actions at times when the invasive plants are most vulnerable and easiest to manage. Follow-up as necessary to prevent the growth of new seedlings.
• Know that invasive species are incredibly resilient. Tailor strategies to the site and consider using several management techniques in combination.
• Prioritize removal techniques that do not disturb the soil. Cut plants off by the stem rather than removing their roots, and spot treat the stump with an ecologically friendly herbicide.
• Herbicides may be necessary as a tool to combat invasive species. There are many types of herbicides, so work with a local ecologist or land manager to determine which are most effective for the target species (e.g., grass, broadleaf herb, or woody plant). Use herbicides only in non-aquatic habitats. Read and follow specifications completely. Use spot-spraying or wick-applicators rather than broadcast spraying, to minimize indirect applications.
• Invasive plants can be very resilient and return after early treatments. Adapt the technique, timing, and tactic to determine the most effective approach. Test various techniques on small plots to determine what works best.
• Consider using a temporary cover crop for large areas of bare soil that are not yet ready to be planted. Cover crops include annuals such as oats, and legumes such as winter peas or crimson clover. Cover crops are fast-establishing but not permanent, and will help to temporarily exclude invasive species from getting established.
• For a more permanent solution after an area has been cleared of an invasive species, replant the area with closely-spaced, fast-establishing, ground-covering native species to prevent the invasive species from getting reestablished.
• Always clean landscape maintenance equipment before moving from an infested area of the site to other areas, to ensure that invasive species are not transported.
• Monitor the site to see if eradication or control efforts are successful, and modify invasive species management tools and methods to improve their effectiveness, as required.