First, the Potentilla palustris, aka march or purple cinquefoil. It is pretty, don't you think?
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According to a botanist friend, Potentilla palustris is an invasive pest, so removing it it a good thing. Check out this official website for more information:
Potentilla
Next, the fragrant water lily (white and pink). Yup, these babies belong in self-contained ponds, not our lakes. This website has some good information on them:
fragrant water lily
For identification of weeds, lists of plants or seeds that are prohibited in Washington, or any other weed into, check out the Washington State Noxious Weed Control Board website.
Instead of invasive plants, I'll leave you with a burst of positive sunshine, courtesy of a cosmos...
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~Aerie-el