March 15, 2019 at 11:45 am #893
What is the best way to manage invasive phragmites?Robert PennerParticipant@docbirdyApril 11, 2019 at 9:33 am #1010
I don’t know if this is the best way to manage, but it is what I have been doing on the Cheyenne Bottoms Preserve here in Central Kansas. We have been aerial spraying cattails for the past couple of years in order to recover our open water and shallow water habitat. We use the lowest amount of chemical required to kill cattail so as not to put excess chemical into the system. Chemical spraying is not a method that The Nature Conservancy implements without weighing all the options, but the landscape has changed dramatically, and we will need to make large scale and sometimes expensive decisions if we hope to maintain any resemblance of a true prairie marsh. Glyphosate labeled for over the water treatment binds tightly to soil. It can persist in soil for up to 6 months depending on the climate and the type of soil it is in. Glyphosate is broken down by bacteria in the soil. Glyphosate is not likely to get into groundwater because it binds tightly to soil. In one study, half the glyphosate in dead leaves broke down in 8 or 9 days. Pure glyphosate is low in toxicity to fish and wildlife. The amount used to control cattails in not strong enough to kill phragmites, so we retreat those stands the following year and this seems to be successful. Shorebird and waterfowl numbers have increased significantly as we have restored more open water and shallow water habitat.April 11, 2019 at 1:57 pm #1011
Thanks Robert! When is the best time to apply glyphosate to manage cattails in Kansas? And in what season do you retreat an area to target phragmites? Do you also use mechanical means for management?Robert PennerParticipant@docbirdyApril 11, 2019 at 2:46 pm #1012
We target cattail spraying between July 1st to September 20th when the cattails are actively growing. We retreat during the same time period the next season. We have done some mowing of cattail in the fall and winter after they have been treated. This seems to speed up the restoration to open water habitat by knocking down the dead plant material and thus exposing any remaining live cattail to retreatment the flowing year by hand spraying or aerial spraying. However, mechanical treatment is totally weather dependent as some of the marshes were dry two years ago but for the past nine months we have been too wet to even get off of the main road. After every site has been treated twice we feel that we can maintain the open and shallow water habitat with regular treatment of the small stands of cattail that will re-colonize in the coming years. It is a fair amount of work but there are significant benefits.Karin M KettenringParticipant@kett0044April 14, 2019 at 11:45 am #1013
Hello everyone — we have short 2 pager on phragmites management that we developed after a bunch of large-scale experiments we did with wetland managers in Great Salt Lake wetlands. I think the treatments are pretty applicable in other regions as well. (We recommend fall spraying.)
Karin Kettenring (Utah State University)
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