Clients are sometimes surprised by how sparse a newly planted garden is. A properly planted garden IS sparse, and one hallmark of an amateur gardener is a lack of consideration for the final size of plants in the garden. Consider the two photographs below.
In the first photograph, newly planted Angel Hair Grass (a species that actually can be planted quite close together) combined with other perennials and a small white buckeye planted correctly yields large expanses of mulch and brown. The second photograph reveals plants that have filled in nicely. Crowded plants are no good in the garden.