My garden isn't red, white and blue. Today it is mostly blue and yellow. However, I was able to find these patriotic colors for you.
RED: I had to search for this color and then I remembered the beebalm on the shady side of the house. This picture could count as red and white if you include the powdery mildew and the artemesia. But I just ignore them and so should you.
WHITE: This spring I had lots of white flowers, but now the most distinctive white is the hydrangea next to the garden shed.
BLUE: So many blues from which to choose. I finally settled on blue larkspur and blue fescue. If you ever planted larkspur, you know that it freely self-seeds everywhere in the garden and the challenge is to edit it so it look like you may have planted it. I hadn't noticed this combination until I took my camera to the garden.