Why do you re-plant the downtown planters and window boxes?

Why do we re-plant the downtown planters when the seasons change?

The downtown planters and window boxes are "Floral Displays". To keep them looking their best year-round it is necessary to replant them as the seasons change. Most of the plants are annuals which means that they grow and die in one season.

Annuals generally have the showiest blossoms that last a long time. Perennials and shrubs have a very short bloom period or don't bloom at all. Additionally, they have a very large root system that crowds out annuals.