In the Garden's many habitats are species from the High Sierra to the serpentine barrens of the Coast Ranges, and from the northern rain forests to the southern deserts. Flowers bloom every month of the year, reaching a spectacular peak in spring through midsummer. In the fall and winter, the Garden is decorated with the vibrant hues of ripening fruits, changing leaves, and colorful twigs. A year-round creek runs through the heart of the Garden, adding beauty, creating a riparian corridor, and providing additional habitat for the many birds, insects, and other animals that visit and live in the Garden.

The Garden's primary role is to create beautiful landscapes displaying California's diverse plant life. Its mission embraces not only aesthetics, but also native plant conservation, public education, and horticultural experimentation designed to bring new native plants into the nursery trade.

Since the Garden's establishment in 1940, its collection has grown to include thousands of plant species and varieties, many identified with interpretive labels. Notable among the specimens from all corners of the state are some of the broadest representations of California's unique plant groups. These include nearly all of California's conifers and oaks as well as collections of California manzanitas (Arctostaphylos), wild lilacs (Ceanothus), grasses, aquatic plants, and flowering bulbs that are among the most complete to be found anywhere.