Why Plant Natives?
A plant is considered native to the area where you live if it existed there naturally before the arrival of European immigrants to California and existed in that space for previous millennia, evolving with other insect and animal life in these local ecosystems. Inland meadows, wetlands, redwood forests, and coastal bluffs are among the many biomes that you can find in Sonoma County. Native plants can be found in each of these ecosystems, some plant species overlapping microclimates and others only thriving in certain conditions.
Green plants are the only organisms on the planet that can turn the energy of sunlight into the sustaining sugars and water that are the foundation of life for all insects and animals. Non-native plants are not nearly as efficient at converting that energy up the food chain. Many non-native plants in a well-suited environment may simply grow and multiply, frequently crowding out some native species, and thereby decreasing the food supply of native insects and other invertebrates; this in turn decreases the food supply for birds, reptiles, amphibians, and mammals. Native insects and other invertebrates use specific plant species for egg-laying, larval feeding, and in preparation for future generations. If the appropriate plant materials are not available, the population of a particular insect may decline dramatically or will move on to a more suitable location nearby. This, in turn, affects the populations of other wildlife. Each species in every habitat contributes to the overall health of an ecosystem.
Large swaths of natural habitat have been altered and/or destroyed across the continent in the past two centuries, and urban spread and infrastructure continue to fragment those remaining. But the home gardener can play an outsized role in the preservation of insect and wildlife populations by creating suitable pockets of habitat space in the suburban world. For additional reading and inspiration on this topic, Douglas Tallamy has written multiple books and articles on the subject. Bringing Nature Home (2008) includes the following statement: “Gardeners have become important players in the management of our nation’s wildlife”.
A discussion of habitat support would not be complete without highlighting that native plant selection is only one piece of the puzzle. In addition to choosing native plant species, the home gardener should consider food and water sources as well as providing shelter for habitat residents. All insects (and wildlife in general) need daily water in some form; plan for this in your garden space. Using large stones, discarded logs and snags, and clumps of native bunch grasses is also recommended for habitat support. Each addition has the potential to increase the biodiversity in your garden space. You may also consider avoiding heavy mulch covering all areas of your garden, as many native bees need exposed soil for nesting. The absence of pesticides and herbicides should also be considered a necessity for creating a vibrant habitat space.
Selecting which native plants to include in your garden may involve several decisions. What role will a particular shrub play in your garden? What food will it produce for wildlife (i.e. pollen, nectar, seeds, fruit)? Is this plant suitable for the area where you live? Plants that can be defined as native to California include species with quite diverse needs. A great source for native species requirements and attributes is calscape.org. This website, supported by the California Native Plant Society, can be a valuable tool in learning details about most every native species in the state.
Choose native species with varying bloom sizes and shapes. For optimum impact this would include a variety of species that will bloom throughout the entire calendar year. Making these choices wisely will increase the biodiversity in your garden, which is in fact, the primary goal for focusing on native species. Also select a variety of plants whose forms vary in shape and size. A mixture of ground covers, perennials, small shrubs, and trees will create three dimensions of diverse wildlife support.