irwin was quoted as saying that the central garden "is a sculpture in the form of a garden, which aims to be art." water plays a major role in the garden. a fountain near the restaurant flows toward the garden and appears to fall into a grotto on the north garden wall. the resulting stream then flows down the hillside into the azalea pool. the designers placed rocks and boulders of varying size in the stream bed to vary the sounds from the flowing water. a tree-lined stream descends to a plaza, while the walkway criss-crosses the stream, which continues through the plaza, and goes over a stone waterfall into a round pool. a maze of azaleas floats in the pool, around which is a series of specialty gardens. more than 500 varieties of plant material are used for the central garden, but the selection is "always changing, never twice the same".