“Native plants give us a sense of where we are in this great land of ours. I want Texas to look like Texas and Vermont to look like Vermont.” — Lady Bird Johnson (First Lady of the United States as the wife of President Lyndon B. Johnson, 1963 – 1969).
Plants define the landscape. In California, besieged by the twin threats of drought and wildfire, the choice to grow native versus non-native plants is attracting more attention than ever before. What exactly are the merits of native compared to non-native plants, and how do gardeners make the best choice about what to grow in a home garden?
Native plants occur naturally in the area where they originally evolved. These plants have coevolved with wildlife, fungi, and microbes, and their interdependent relationships form the foundation of our native ecosystems (Native and Naturalized Plants for the Home Garden in Northern California, p. 1).
With this stunning variety of native plants, you might expect to see them growing on every corner and offered for sale in every nursery and home improvement store, yet this is not the case. In fact, according to the California Academy of Sciences, 75% of the original native plant habitat in California has been lost (Hotspot: California on the Edge, p. 2).
Since California natives are less commonly planted compared to non-native plants, you can become more familiar with them by visiting a local native plant garden such as the Butte County Master Gardeners Demonstration Garden at Patrick Ranch in Durham, the Alice B. Hecker Native Plant Garden at Chico Creek Nature Center, and the Native Plant Pollinator Garden at Gateway Science Museum in Chico.
But how do we know for sure that a plant really evolved in the local area? Botanical studies of the world's flora have been ongoing for many years, and the historical record includes many specimens and drawings of plants that were originally brought to America by European explorers and settlers. In addition, paleobotanists have been able to compare fossil records with modern plants to accurately identify which plants are native to an area (Native and Naturalized Plants for the Home Garden in Northern California, p. 2).
Another advantage to native plants is that once they are established, they normally need little watering beyond normal rainfall. With California experiencing an historic drought, native plants can help save significant amounts of water that would otherwise be soaked up by thirstier landscape plants. In general, native plants require less maintenance than non-native garden plants: less water, little or no fertilizer, less pruning, less of your time.
In addition, California native plants attract wildlife that use these plants as their natural habitat. For example, the many pollinators that flock to native plants can improve fruit set in your home orchard and yield in your vegetable garden. A variety of native insects and birds can reduce populations of mosquitos and plant-eating bugs. By using native plants, you support native wildlife and help preserve the balance of natural ecosystems (Benefits of California Native Plants).
“California has the greatest natural botanical diversity of any state in the United States. In addition to nearly 5,000 native plant species, there are about 1,500 non-native species that have become established in the state. About 250 to 300 of these are weeds of agricultural crops, turf, or gardens. The remaining 1,200 or so are naturalized plants of wildlands or disturbed non-crop areas, some of which are important invasive plants” (UC IPM Pest Notes: Invasive Plants).
Invasive plants can “disperse, establish and spread without human assistance,” and they cause disruption of natural ecosystems. The worst invasive species are called landscape transformers because they substantially alter the “character, condition, form and nature of the invaded habitat,” consuming resources needed for native plants to survive. When invasive plants replace native plants in the wild, wildlife that feed on the native plants suffer and may become endangered. (UC IPM Pest Notes: Invasive Plants, pp. 1-2).
Home gardeners may be surprised to learn that commonly available plants such as periwinkle (vinca major), or butterfly bush(Buddleja davidii), are listed on the California Invasive Plant Council Inventory, as are sweet alyssum (Lobularia maritima), and gazania daisy (gazania linearis). Periwinkle, English ivy, Himalayan blackberry, and Chinese pistache, among others, have invaded our own beloved Bidwell Park. You may be dismayed to realize that you are growing invasive plants in your own garden! The University of California's division of Agriculture and Natural Resources has information on how to determine whether a plant in your garden is safe to keep or should be removed (UC IPM Pest Notes: Invasive Plants, p. 7). The potential for a plant to spread from your garden to surrounding natural areas is a critical consideration in deciding whether to keep an invasive plant or destroy it.
When you shop for plants, “the key element is to know which horticultural plants are invasive in your area of the state. If a plant is listed as invasive in your region, it should be avoided for landscape use, especially for locations near natural areas. It may be safe to use in other regions, but sometimes the plant is not listed as invasive in an area merely because it has not yet become a presence” (UC IPM Pest Notes: Invasive Plants, 7).
Another fine resource for Butte County gardeners interested in planting responsibly is the list of Butte County All-Star Plants developed by the Master Gardeners and based on their experience at the Demonstration Garden at Patrick Ranch. These are plants that grow well in the local area. Almost all them are drought tolerant or require only moderate watering, and some are also California natives.
Gardeners interested in planting California native plants will appreciate the CalScape website where you can enter your address and search for plants that are native to your area. The search results are categorized in useful ways including low/very low water, butterfly hosts, very easy to grow, shade/part shade, annuals, perennials, and more. The information on each plant also details how the plant provides habitat for wildlife.
Clearly, home gardeners can support the health of natural ecosystems and conserve water in California by making wise choices about landscape plants. With non-native plants, make sure a plant is not invasive (or potentially invasive) before purchasing it, and be aware of its water requirements. Ultimately, California native plants are the best and most responsible choice, especially because of the ongoing drought and their diminishing natural habitat. The one drawback of native plants, perhaps, is that they can be harder to find; fortunately, the Butte County Master Gardeners program offers twice yearly plant sales featuring native plants at reasonable prices. One native plant at a time, home gardeners can help “California look like California” again in all its marvelous biodiversity.
Works Cited and References for Further Information
Benefits of California Native Plants, California Native Plant Society
California Invasive Plant Council Inventory, California Invasive Plant Council, 2006-2021.
CalScape, California Native Plant Society
Castillo, Dava, and Elkins, Rachel, Native and Naturalized Plants for the Home Garden in Northern California, The Regents of the University of California Agriculture and Natural Resources, 2009.
DiTomaso J.D., Bell C.E., Wilen C.A. 2017, UC IPM Pest Notes: Invasive Plants, ANR Publication 74139.
Hotspot: California on the Edge, California Academy of Sciences, 2005.
PlantRight, Plant California Alliance, 2019
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at email@example.com (preferred) or call (530) 538-7201.
By Laura Lukes, UC Master Gardener of Butte County, September 7, 2018
The beauty of evolution is its reliance on trial and error, or adaptation. What works, works very well, and allows life in many forms to exist in some of Earth's harshest environments. The climatic conditions of the planet's seven Mediterranean Zones include between five and seven months of zero precipitation, and many days in a row with high temperatures of over 100 degrees Fahrenheit. These are challenging circumstances for any living thing. Yet a wide variety of plants have evolved clever strategies to survive these long, dry, hot periods.
Generally speaking, there are three major strategies employed by plants to survive annual drought conditions: desiccation tolerance; drought avoidance; and drought tolerance. These strategies evolved through millions of years of adaptation, and are endlessly fascinating in their ingenuity. (Please note that the survival tactics described below, the result of complex chemical and molecular biological processes, are simplified for this article.)
Desiccation Tolerance: To desiccate something is to thoroughly dry it. Tolerance of desiccation gives a plant the remarkable ability to survive almost total dehydration. This strategy is employed by mosses and ferns. Briefly, plants in this category have developed the ability to enter into, and recover from, anhydrobiosis, the cessation of metabolic activity as a result of low intracellular water content. Next time you are hiking in Upper Park or the foothills during the dry months, you can see this phenomenon for yourself. Find a patch of rust colored, crunchy dry moss on a rock, and gently pour a small amount of water on it. In seconds, what appeared to be completely dead vegetation will turn green and supple.
Another form of drought avoidance is early leaf drop. A good example of this is the buckeye (Aesculus), which occupies a unique ecological niche by being one of the first shrubs to leaf out and flower in early spring, and also one of the first to lose its leaves, well before the onslaught of summer heat and drought. Leaves demand precious nutrients and energy, and without them the buckeye can conserve these resources. During years of drought, and during sustained periods of high temperatures, our valley oaks and blue oaks lighten their metabolic load by dropping some leaves earlier than usual.
Drought Tolerance: Lastly, there is this catch-all phrase. Plants in this category are just better at functioning during annual drought conditions, due to a number of creative adaptations. Such plants are also called xerophytes; literally “dry plants.” They remain green all year round, but manage to save or store water, often through structural (usually leaf) morphology. Common structural adaptations for water conservation are:
- Thick, leathery leaves with waxy cuticles, which perform dual functions of cutting down on water loss and reflecting heat away from the plant. Our native Ceanothus (California Lilac) is a prime example of this.
- Small, thin leaves, which effectively reduce the surface area from which water loss can occur. The tiny yet highly fragrant leaves of Santolina typify this adaptation.
- Sunken stomata pits, which trap moist air and reduce water loss rates. Pine needles employ this strategy (as well as being small and thin).
- Hairy leaves, like those found on Cyprus ironwort (Sideritis cypria) or Lamb's Ears (Stachys byzantina), which shade the stomata and reduce contact from hot air, protecting plants from extremes of light and temperature.
Redundancy is a hallmark strategy for species survival (think two kidneys in human beings); and most plants employ more than one method of beating the hot dry summers of the Mediterranean climate. Now that you know what to look for, see how many of these ingenious biological adaptations you can spot.
By Jeff Oster, UC Butte County Master Gardener, October 25, 2017.
Western Redbud, California Buckeye, Toyon, and California Flannelbush are all plants in this category that attract pollinators, provide interest over several seasons of the year, and can be grown in a number of different gardening environments. They are especially effective planted in groups for repetition of form, and can create informal hedges or provide a backdrop for smaller plants.
Western Redbud (Cercis occidentalis) is native on dry slopes of the coast ranges and Sierra Nevada foothills to 4500 feet and eastward to Utah (usually situated next to a spring or seasonal creek). It is a deciduous, multi-trunked shrub or small tree with a long life span, growing two to three feet per year and reaching to six to twenty feet over time. Magenta flowers appear in February to April before the leaves, and last for two to three weeks. The leaves are kidney-shaped and bluish-green; they can provide a lovely garden backdrop for summer-blooming plants, and turn yellow in fall. Reddish-purple seed pods hang from the branches in winter. The bushes are impressive in groups.
Western Redbud likes full sun, and will grow faster if given some summer water. It will tolerate clay soils and soils with lime or acid (pH levels 5.5 to 8). It can provide good stabilization along a ridge or bank. The roots perform the useful role of fixing nitrogen. A good winter chill is necessary for good flower set. The flowers and young pods are edible; the plants will self-seed.
Western Redbud attracts hummingbirds, goldfinches, butterflies, and bees (including leaf-cutter bees) to its flowers. It is deer resistant, and resistant to Oak Root Fungus. While generally pest-free, Western Redbud is susceptible to caterpillars and scales, and to crown and root rot.
California Buckeye will grow in conditions ranging from partial shade to full sun, and it is drought tolerant but needs regular water during the first few years. It will tolerate clay and serpentine soils (pH 4 to 8) and seasonal flooding, and is useful as a slope stabilizer. In the garden it will drop leaves early (going summer dormant) if it gets dry; otherwise leaves will drop in the fall.
The nectar of the California Buckeye attracts hummingbirds, native bees and butterflies.
California Buckeye is poisonous to livestock, Asian honey bees, and fish. Its seeds are toxic unless processed. It is deer-resistant.
While Toyon likes full sun, it can tolerate full shade, and will grow in a variety of soils (pH 5 to 8), and can help stabilize a ridge or bank. It is drought tolerant after a few years, but will tolerate some water if drainage is good.
Toyon attracts a wide range of pollinator insects including native bees, pollinator flies, and butterflies. Winter fruit attracts cedar waxwings, towhees, finches, flickers, grosbeaks, bluebirds, robins, thrushes, mockingbirds, quail, tanagers, warblers and sparrows. Often the ripe berries ferment before they are eaten, so birds may get a little tipsy. Mammals, including coyotes and bears, also eat and disperse the berries.
Toyon is susceptible to fire blight and root rot (if over-watered). Over time, it will become deer resistant.
California Flannelbush likes sun to part shade. It is drought tolerant and needs no summer water but must have good drainage, preferring well-drained (sandy) soils (pH 6 to 8) near natural drainage channels (placement along the top of a riverbank is ideal.
California Flannelbush attracts bees and butterflies, has few pest problems, and is deer resistant.
The following two charts refer to plants referenced in the three part series on native plants that thrive in Chico and Lindo Channel.