What are "Invasive" Weeds?

Invasive plants are non-native species that have the potential to cause harm to ecosystems, the economy, and human and animal health. By competing with and displacing native plants, invasive plant infestations can alter plant community structure, nutrient cycling and hydrological processes; increase soil erosion and sedimentation; and reduce species diversity and ecosystem productivity.

Why should I care?

Due to its remoteness and intact ecosystems, Southeast Alaska has suffered fewer impacts from invasive plants than other states. However, invasive plants are becoming more prevalent in the region, and more than 30 species of invasive plants have been found in Juneau alone. Most invasive plants found within the City and Borough of Juneau (CBJ) occur primarily in developed areas and along roadways and trails. Unless action is taken to control and eliminate these invaders, these species will eventually invade Juneau’s intact wetland, forest, riparian, and coastal ecosystems. Unchecked, invasive plants could ultimately impact local fishing and tourism industries as well as diminish the quality of life in Juneau, Alaska.

What can I do?

You can help manage invasive weeds. But please keep in mind that many invasive plants have spines and/or toxic or irritating substances. Whether controlling weeds manually by hand pulling, or by applying herbicides, be sure to take appropriate precautions by wearing the appropriate protective clothing (gloves, boots, safety glasses, etc.). Before using herbicides, always read the label and follow instructions! Contact the JNU-CWMA for information regarding control options and possible assistance.

The key to effective invasive plant management is integration of all available options for a particular plant species, site, and situation. Take time to develop a long-term management program, focusing on four strategies: prevention, early detection, rapid response, and site rehabilitation.

1. Prevention
Prevention is the best approach to managing invasive species. It takes much less time and money to prevent an introduction than it does to manage one that has spread throughout a landscape. Prevention techniques include educating the public to identify and report invasive species of concern; implementing programs for invasive free straw, hay, and gravel pits; promoting weed-free products in construction and remediation; and working with greenhouses and nurseries to offer alternatives to popular invasive plant species.

Keeping weeds from becoming established should have the highest priority in management programs. Learn seven simple steps to stopping invasive plant infestation and spred in Juneau.

Early Detection
It is important to recognize invasive plants before they become established. In order to do this, it is important to be able to identify invasive plants in the seedling or immature stage in addition to the flowering or mature stage. Once a plant has set seed or become established, the amount of effort to manage the plant increases. Known infestations must be contained and prevented from spreading to uninfested areas. If you find a weed that appears to be invasive, please contact the Juneau CWMA at (907)586-6878 or info@juneauinvasives.org or report your finding to EDDMapS Alaska for action.

Rapid Response
When developing a management plan, emphasis must be placed on timely action. Rapid response to an invasive plant problem reduces the amount of time, energy, and funds required to keep populations in check. Management options will vary with each weed species. For example, annual and biennial weeds can sometimes be managed with timely cultivation (i.e., before seed set). Harvesting, hand-pulling, and tarping are also effective non-herbicidal treatments. As a last resort, herbicides registered for invasive plants have proven effective in certain situations.

Rehabilitation
Initial efforts to manage invasive plants prior to rehabilitation efforts may include the use of cultivation, herbicides, and/or biological techniques (check with the Department of Agriculture before using biological control techniques). Invasive plants often appear in disturbed soils, along roadsides, and after construction activity. If nothing is done to rehabilitate or enhance the infested site once invasive weeds are removed, another undesirable species can take the place of the weed that was removed. Site rehabilitation may entail reseeding an area, or it may simply involve enhancing the competitive ability of the desirable plants that are still viable on the site. An important part of rehabilitation involves considering the inherent production potential of the site itself (soils, precipitation levels, and topography, etc.).

For more information on site revegetation, refer to A Revegetation Manual for Alaska (Adobe .pdf, 4.87 MB) from the Alaska Plant Materials Center.

Invasive Plant Management List

JNU-CWMA Invasive Plants of Concern

After prevention, early detection and rapid response (EDRR) is the most cost-effective approach to managing non-native, invasive plant species.  EDRR involves constantly looking for invasives that are rare or that have yet to arrive in the CBJ.  When a population of rare or new invasives is found, JNU-CWMA and its partners will control that population to prevent its spread.  JNU-CWMA has developed a managment list to assist managers and concerned citizens in performing EDRR in the CBJ.