To make a garden work from Spring to fall you should always plant Perennials with beautiful fall foliage, so that when the Spring and Summer blooms are spent, the fall foliage can take up the slack. Another tip is to plant taller plants in the back but still keep in mind the theme of Spring to Fall.
Some Perennials with very pretty foliage are; ribbon grass, maiden grass, Japanese iris, hostas, lady's mantle, astilbe, and a variety of heather's.
Contemporary Landscape by Lincoln Landscape Architects & Landscape Designers Benjamin Vogt / Monarch Gardens
Traditional Landscape by Atlanta Landscape Architects & Landscape Designers Home & Garden Design, Atlanta - Danna Cain, ASLA