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We bought a house in the winter and once the snow cleared and things started growing, we noticed this low laying plant covering large sections of our lawn. It is mostly in the very shady areas and completely takes over those areas.
It is nice to look at, and where it is there is so much shade I would need to plant a shade grass. I don't mind it, as long as it stays in place and doesn't try to take over the rest of the yard.
EDIT I live in Minnesota so I get lots of ice and snow (most winters).