Invasive phragmites is a non-native aggressive perennial grass that has quickly colonized many wetlands, roadside ditches and shoreline areas in Northeastern Wisconsin and has recently become a huge environmental concern.
Invasive phragmites is a non-native aggressive perennial grass that has quickly colonized many wetlands, roadside ditches and shoreline areas in Northeastern Wisconsin and has recently become a huge environmental concern. Phragmites can reach up to 15 inches tall, and its root can spread up to 60 inches laterally.
Small patches of phragmites can be controlled through a bundle, cut and chemical treatment method. In this technique, the canes are tightly bundled with twine at waist height, cut above the twine, and the surface of the cut ends is treated with an appropriate glyphosate product labeled for a site specific situation.
If the patches are in standing water or in a wet area at the time of treatment, use glyphosate products labeled for aquatic use (Rodeo), but make sure to get a permit from the Wisconsin DNR before treating the patch.
For dry land sites, terrestrial glyphosate products can be used and no permit is required. Herbicide solutions that are applied should contain at least 20 percent glyphosate to be effective. Always read the herbicide label before applying the product, and wait at least two weeks after the treatment to let the canes die.
The ideal time to implement this bundle, cut and chemical treatment technique is from late July until September before the first killing frost occurs. The dead canes can be mowed by using a small mower or weed whip. In wet sites you should wait until the ground is frozen. Bag the mowed plants in a clear garbage bag, label them as invasive plants, and dispose in a landfill.
Evaluate the treatment success in the following growing season. If there is any re-growth, treat with a foliar application of glyphosate. Studies have shown that constant mowing of the plant during the growing season is ineffective as the rhizomes can readily re-sprout and further increase their dense stand.
Land managers dealing with large stands of phragmites can contact Mary Gansberg, DNR Water Resources Management Specialist, at 920-662-5489 or Joe Henry, DNR Regional Ecologist, at 920-662-5194 for more information and permits.