or Sulfur Cinquefoil
Another “introduced species”, this tall flower of pastures, roadsides, and railroads has spread across the entire United States. In some states it is considered a noxious weed.
Sulfur cinquefoil flowers are usually soft yellow, but sometimes they are white. Each of the 5 petals is shaped like a little heart. The distinctive leaves are palmate, with 5 to 7 hairy and strongly toothed leaflets. See the photos below for more detail.
As far as I am concerned, weed or not, this is a beautiful little wildflower! Bloom time is summer.