Tellima grandiflora - Fringecups
This is a common garden invader in woodland edges, often beside streams. In that it is similar to another invasive plant of woodland, Pick-a-back-plant Tolmiea menziesii.
Both are members of the Saxifrage family.
Tellima grandiflora has bigger heart-shaped, bluntly-toothed leaves. The flowers are only on one side of the stem with deeply-fringed petal lobes that start white-green and turn pinkish.