Planting perennials as the core of your landscaping and filling in with annuals based on the season can be a cost-effective way to ensure interest and color all year long. In my front bed (shown above), the perennials are already well-established and consist mostly of shrubs and groundcover.
Since I was on a tighter budget this year but still craving that burst of color for spring/summer, I got resourceful and divided two large mounds of perennial white Mexican petunias into 12 smaller clusters and spread them throughout the front of the bed in a checkerboard pattern. Then I purchased 24 dark purple salvia plants and four 1-gallon snapdragon mixes to fill in the gaps (shown below).
Like icing on a cake, you don't want to skip the mulch! It not only provides vital nutrients to the soil and captures moisture for the plants, but you can't deny it's aesthetic value. When I put down a fresh layer of mulch, it makes everything look new even though only a few of the plants have changed.
All in all, I spent $21 on flowers and $6 on mulch for the front bed that should last me until the fall. Not a bad price for instant curb appeal!