Yarrow has also become a popular garden plant, and has many horticultural varieties. Pink flowered plants are not unusual in the wild, including at Ives Preserve, where is image is from. Uh, oh!
There, I'm back. Had to take a puppy break. Now he's in the back yard and my toes are safe. North American yarrow are a mixture of native and introduced strains. They are impossible to sort out at this point, though many older botanical texts try. Boreal and alpine plants certainly present differently than ones from more moderate habitats. But plants of all kinds look different if growing in difficult environments.