Most flower gardeners enjoy sequences of bloom in their beds. This can be achieved by having enough different varieties of perennials that there is always bloom in one bed by different plants at different times.
Or if one has a number of different beds, each can feature plants that bloom at different times so that the focus of attention moves from bed to bed across the growing season.
Additionally, if annuals are incorporated in the plantings, they can provide color in the foreground of beds that also contain taller perennials that bloom in complimentary colors at various times during the growing season.
For example, a bed might contain daffodils and other spring bulbs early on, and then their foliage is later concealed by day lilies that grow up to hide the decaying bulb foliage.
Clumps of peonies and iris that bloom in late spring and early summer and clumps of asters and chrysanthemums for the fall display can also be included. For example, a garden with four beds where the focus shifts between them might have one bed of spring bulbs combined with perennials and cranesbill geraniums to come up as the bulbs die down. The next bed to bloom could be peonies and iris, and the next could be purple salvia and yellow achillea. The fourth could be made up of fall bloomers including perhaps some shrubs with berries.