Confidence: I'm as sure as I can be.
Notes: To early for the Viburnum plicatum 'Mariesii'. This is Candytuft which is more of a sub shrub, thought I can't get it down to species level, could be either I. semperflorens or I. sempervirens. The four petals show it is in the Cruciferae family.(Brassicaceae).