California Native Plants verses Mediterranean Adapted Plants
Native to Southern California, Matilija Poppies boast one of the happiest flowers, bringing cheer to any garden.
Many people are confused about what a California Native plant actually is. Even landscape professionals often talk about “native gardens,” when they are actually referring to Mediterranean-adapted gardens. These so-called “native gardens” sometimes include plants that are invasive species, which can have negative ecological impacts and threaten native plant populations in wild land spaces. So, what is a California Native plant, a Mediterranean adapted plant, and an invasive plant species and why is it important to understand the difference?
A California Native plant has evolved here in California over a long period of time without human influence. These plant species have co-evolved with native biota in the soil as well as native animals, creating the foundation of the local ecology. California Native plants are great options to include in a landscape design for many reasons, but let’s look at the two main reasons. The first is that California Natives are adapted perfectly to survive in our environment. Our soils are the soils these plants have adapted to thrive in, eliminating the need for fertilizer. California Native plants are also adapted to our weather patterns and precipitation rates— reducing and, in some cases, eliminating irrigation needs. Plants that have evolved in our region have adapted to thrive with minimal external inputs.
California poppies, Monkey flower, Abutilon palmeri and Penstemon azureus are all California native plants
The second reason to include California native plants when designing your garden is that they help support local fauna such as birds and insects. These birds and insects work to keep pest problems at bay and feed the soil. As native birds and insects’ flit from plant to plant they prey on problematic pests and spread pollen. While feeding, they deposit droppings onto the soil. These droppings serve as manure providing nutrients for the plants. Plant communities are the backbone of the food chain—when one link in that chain breaks it can have ripple effects. As more and more of our back country and open spaces become developed, it is our job to create spaces that allow us to co-exist with nature.
California is considered a biodiversity hot spot, boasting some of the greatest plant diversity in the world. With over 7,000 native plants—most of which are not found anywhere else in the world—we are provided a vast palate to work with. It is possible to create unique landscape designs to fit a variety of architectural styles while including California Native Plants.
Planting California native Toyon in your garden provides important forage for Cedar Waxwings.
Southern California has the Mediterranean climate. Mediterranean climates are found in west-facing coastlines located roughly 30 to 45 degrees north and south of the equator. In these regions, the climactic characteristic includes hot dry summers and mild, wet winters. Other Mediterranean regions include parts of Chile, the West coast of Australia, South Africa and of course the areas surrounding the Mediterranean Sea. Because these areas share a similar climate, their native plants have similar adaptations that allow them to thrive in our region as well. These plants are considered Mediterranean-adapted plants.
This garden is thriving on very little water, yet none of the plants with the exception of the oaks are California native. Instead these are Mediterranean adaptive plants.
I love these Mediterranean adapted plants and often use them in my planting plans. Because they are adapted to our climate, they tend to have low water requirements. The way nutrients cycle in these arid, “Mediterranean” regions worldwide makes these plants do well in California’s soils without a lot of extra inputs. However, there are a few aspects of these plants that fall sort of characteristics of California native plants. Firstly, Mediterranean-adapted plants have not co-evolved with our animal communities, even if many of these plants do provide forage for beneficial insects. If you ever listen to a rosemary hedge or lavender bush on a warm day, you can hear that in the buzzing of hundreds of bees, but California Native Plants provide nourishment to a greater variety of California native animals. It bears repeating that due to the extensive development of wild lands in California, we need to help preserve native species by including them in our landscapes.
This image features 3 different Salvias commonly known as sages and Stachys byzantina commonly know as Lamb’s-ear. Although there are a lot of California native sages and native Stachys the plants pictured here are not native.
Lastly, let’s look at the issue of invasive species. Many invasive plant species fall in the Mediterranean-adapted plants category. What are invasive plant species? Invasive plant species are plants that are introduced into an area through human activity, but spread and propagate in wild land areas. To an untrained eye, these plants may appear to be native because they are so prevalent in the wild lands of Southern California. Some of these plants are very attractive (which is why they were brought here in the first place), but these plants can cause a lot of problems. Invasive plants can out compete native species, leading to mono cultures that do not support local wildlife. Some invasive species carry higher fuel loads causing hotter, more- destructive wild fires. Invasive plants have the ability to reshape the land by effecting waterways, destabilizing hill sides, and increasing the possibilities of mudslides and flooding in winter storms.
Although you may have seen these plants on a recent hike these plants are not native. In fact they are incredibly invasive plants causing lots of trouble in out open spaces. Going clock wise Mexican feather grass (Nassella tenuissima), Vinca, Pampas grass (Cortaderia selloana), Ice plant (Carpobrotus edulis), Fountain grass( Pennisetum setaceum), and Shinus molle with is sometimes even called California pepper tree. Please do not plant therein your landscape.
If your landscape is adjacent to a wildland space, the impact of using invasive species is greater. But gardens in more urban and suburban settings also pose a threat when including invasive plant species in the landscape. Plants are spread by wind, carried by water after rains, and by birds and other creatures.
After hearing about the problems surrounding invasive plant species people often say, “Those plants should be illegal to sell.” However, plants’ potential for being invasive are so regionally specific, and new species with the potential for being invasive are constantly being introduced in the nursery trade. Therefore, it would be impossible to legislate again them. Moreover, there is very little consciousness and education in this department and nurseries are full of plants and seed that are, or have the potential of being, problematic invasive species.
I am not a native plant purist. I see value in including plants from around the world in our built environment, but it is important to consider each plant we plant—what purpose it severs and what effect it has on our local ecology. A beautiful garden is great, but a beautiful garden that grows in a harmony with nature is better. Understanding what plants are native, what plants work in our climate, and what plants can cause problems in our ecosystem is important. With this knowledge we can make better decisions in a landscape design, and these decisions can have huge effect on the safety and resilience of our communities.
To learn more check out
CAL-IPC, California Invasive Plant Council
California Native Plant Society website Calscape
Plant Right
Sweet Smiling Landscapes, Landscape Design
https://www.sweetsmilinglandscapes.com
Serving Santa Barbara including Goleta, Montecito, Carpinteria as well as Ventura and Ojai