California

The Garden is home to one of the largest species collections of California native plants in the world, including more than 200 plants that are on the California Native Plant Society’s list of rare and endangered species. Our conservation program includes propagation of many of these endangered species.

The great variety of plant communities in California has evolved in response to the state’s vast geological, topographical, and microclimate diversity. In this collection we group plants by these communities:

Alpine Fell-Field: Alpine fell-fields are rock-strewn habitats exposed to extreme weather and intense sunlight, such as high mountain elevations. These are challenging habitats: plants growing in these locations may be covered in snow from September through June or July, making for a shortened growing season.

Chaparral: Chaparral, a dense thicket of shrubs or dwarf trees, is the most common vegetation type in California. Its foliage has adapted to hot, dry conditions with thick, leathery leaves that conserve moisture. The word “chaparral” derives from the Spanish chaparro, meaning scrub oak (such as Quercus berberidifolia). Because chaparral is a fire-dependent biome, plants within this community have evolved ways of coping with periodic fire events.

Coastal Beach and Dune: Dune and coastal plants must tolerate difficult and highly variable conditions such as shifting, sandy soil that is low in nutrients; high winds; and cool, foggy weather alternating with harsh sunshine. Observe how many of our dune plants, such as the coast buckwheat (Eriogonum latifolium), hug the ground and exhibit light gray and silver colors to reflect the sunlight.

Desert: California deserts include Mojave and Sonoran communities. This collection shows plants with broad distribution.

Oak Woodland and Pine Forests: Much of California’s terrain is occupied by woodlands and forests, which vary in flora depending on the climatic and edaphic (soil) conditions of the region. These woodlands and forest communities typically feature multiple layers, with shade tolerant shrubs, herbaceous plants, and vines growing under the tree canopies. California boasts the world’s tallest tree coast redwood, (Sequoia sempervirens), largest tree, giant sequoia (Sequoiadendron giganteum), and oldest tree, bristlecone pine (Pinus longaeva). Coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum) are on display here at the Garden.

Pygmy Forest: In a few isolated places along the Northern California coast, unique geological forces over the past 500,000 years have produced a sort of ecological staircase: terraces in the coastal scrub and forest—each about 100 feet higher and 100,000 years older than the one below it. These terraces are underlain by a clay hardpan and very thin, acidic soils have developed, resulting in a pygmy forest of stunted trees and shrubs.

Redwood Forest: The majestic redwood (Sequoia sempervirens) occupies a narrow strip along the Pacific Coast, from central California to southern Oregon. Fog is essential for sustaining redwood forests through the dry, summer months, keeping these trees close to the coast. Though few plants can grow in the deep shade of a redwood forest, redwood sorrel (Oxalis oregana) and wild ginger (Asarum caudatum) create a lush carpet.

Riparian: The term “riparian” refers to plant communities growing adjacent to rivers and streams. Plants often grow quickly with ample moisture, and have often adapted to flooding and the deposit of debris and sediment. Willows (Salix ), cottonwood (Populus), and alder (Alnus) may create a lovely tree canopy, while plants like spicebush (Calycanthus occidentalis) and dogwood (Cornus) might form an understory thicket.

Serpentine: Serpentine refers to a unique type of rock serpentinite formed deep within the earth and thrust to the soil surface by colliding tectonic plates. Their unique geology causes serpentine soils to be very low in important plant nutrients, while high in certain toxic metals. Found scattered throughout the coastal range and a few areas in the Sierra Nevada, serpentine plant communities make up about 1% of California’s land area. The Garden’s serpentine display was created from rock and soil from serpentine sites, and features unique species of manzanita (Arctostaphylos), Ceanothus, leather oak (Quercus durata), and cypress (Hesperocyparis).

Freshwater Marsh: Before European settlement, freshwater marshes covered much of the Great Central Valley. Freshwater marshes are tremendously important for many migrating birds and other wildlife, but today the vast majority of these wetlands have been drained for agriculture and development.

Vernal Pool: Typically occurring within grassland ecosystems, vernal pools result from the seasonal ponding of winter rains in depressions with an impermeable soil or rock layer. The vernal pool environment is flooded for too much of the year for upland species to grow, yet it is too dry in the summer for wetland plants. A unique vernal pool plant community has evolved, made up of annual grasses and wildflowers that germinate, grow, bloom, and produce seeds sequentially as the pond waters recede in the spring, often producing concentric rings of plants. Our vernal pool is planted each winter with plants started from seeds in the Garden’s nursery.

Grassland: Historically, grasslands have occupied at least 10% of California’s land area, especially in and around the Central Valley and larger Coast Range valleys. Grasslands are particularly well suited to areas of high temperature and low rainfall where trees and shrubs are less abundant. California’s state grass, the purple needlegrass (Stipa pulchra), may grow roots down to 5 meters (16 ft) and live for more than 100 years.