Appendix L
Maintenance Level Guidelines
although established plants can tolerate drier conditions. Purple loosestrife spreads mainly by seed, but it can also spread from root or stem segments. A single stalk can produce from 100,000 to 300,000 seeds per year. Seed survival is up to 60-70%, resulting in an extensive seed bank. The absence of natural predators, like European species of herbivorous beetles that feed on the plant's roots and leaves, also contributes to its proliferation in North America. The plant's ability to adjust to a wide range of environmental conditions gives it a competitive advantage; coupled with its reproductive strategy, purple loosestrife tends to create monotypic stands that reduce biotic diversity. Purple loosestrife displaces native wetland vegetation and degrades wildlife habitat. As native vegetation is displaced, rare plants are often the first species to disappear. Eventually, purple loosestrife can overrun wetlands thousands of acres in size, and almost entirely eliminate the open water habitat. The plant can also be detrimental to recreation by choking waterways. By law, purple loosestrife is a nuisance species in Wisconsin and Illinois. It is illegal to sell, distribute, or cultivate the plants or seeds, including any of its cultivars. Control The primary control season is mid-July through mid-August. Plants are treated with the herbicide Rodeo, with a concentration of active ingredient of 10% in water. (Rodeo is a form of the herbicide glyphosate that has been formulated for use in and around water.) The method preferred by the Wisconsin Department of Natural Resources is to traverse the wetland on foot. Once the target (Purple Loosestrife) is located, tear or cut off the inflorescence (flower cluster). If early enough in July, and the plants are not beginning to make seed, the inflorescence can be discarded on the ground. If seed production has already begun, the inflorescence must be bagged and removed from the site. With the paintbrush herbicide applicator, paint each stem of the loosestrife plant from the top down about 3 feet. Be careful to get as many of the stalks painted as possible. Applying herbicide with a paintbrush (instead of a spray bottle) ensures that the chemical is confined to the stem. It is important to recheck the eradication area again approximately two weeks later and treat any plants that were missed and are still alive. To make the Herbicide Applicator: A wood-handled paintbrush is affixed with a screw inside a wide- mouthed plastic water bottle (Nalgene). Cut the top of the paintbrush square and to a length so that it just reaches the bottom of the bottle. It is important to seal around the screw and washer with glue so that the herbicide cannot leak out. In use, hold the paintbrush containing herbicide by the plastic top and wipe off the excess liquid before painting the loosestrife stems.
- Contributed by Richard Staffen, Bureau of Endangered Resources, Wisconsin Dept. of Natural Resources
-http://www.ipaw.org/invaders/loosestrife/index.aspx
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470 Naperville Park District | 2023 MASTER PLAN
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