Water Pennywort (Hydrocotyle umbellata) is a very common perennial aquatic weed that will form dense mats that creep along shorelines of ponds, lakes and marshes. It has bright green round leaves that alternate on a long stem. These circular leaves are typically the size of a half dollar. Long stems are attached at center of each leaf. Water Pennywort has delicate clusters of tiny 5-petaled white flowers. It reproduces from seed or roots. There is no known biological method of control.
1) Physical removal is an option for seed and root reduction. This method can be difficult because new weeds can sprout from seeds and root fragments left behind.
2) Aquacide Pellets are a systemic aquatic herbicide that is best applied early spring as new growth begins to appear. Repeat treatment 3-5 weeks after the first application may be needed to kill the entire root system.
3) Aqua Neat Liquid and Shore-Klear Liquid are a second systemic option best applied mid-season when all the weeds are above the water surface and in full bloom. Again, repeat treatment 3-5 weeks after the first application may be needed to kill the entire root system.
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