Let’s start with a simple color wheel which is essentially the colors of the rainbow arranged around a circle. Note that on one side of the wheel are what we call warm colors -- yellows, oranges and reds.
Warm colors appear to come forward in the landscape, and seem closer than they really are. They make big spaces feel smaller. Use them to draw the eye toward features you want people to notice or away from eyesores. Here, your eye follows the yellow flowers to the trees in the background, de-emphasizing the buildings on either side.