Carpobrotus edulis is an invasive plant species in California commonly known as the iceplant. Originally from the coastal habitats of South Africa, iceplants are commonly used today in California landscaping for their low-maintenance and beautiful, succulent features. One of many reasons iceplants are an invasive species in California is exactly because of this. In fact, they are so widely used that there are 8 different varieties of iceplants found just in Orange County.
Invasive species are non-native species that harm the native biodiversity of an environment. In the case of iceplants, their adaptations have allowed the plant species to thrive in California’s climate and ultimately outcompete native plant species, alter soil compositions, and even offer shelter for other non-native species like the black rat. Iceplants have a fibrous root system, which means that their roots branch out from the plant’s stem. Their roots allow for the plant to spread quickly and create mats over the ground, which prevents other plants from growing. The domination of one particular plant over a large area can be problematic when plants like invasive species offer little to no beneficial services to the ecosystem. Moreover, the leaves of iceplants can secrete large quantities of salt that fall into the soil, which can prevent other plants from being able to grow near it, allowing it to spread even further.
When they were introduced to California in the early 1900s, iceplants were used to address soil erosion, specifically alongside railroad tracks across the state. Because of how aggressive their roots are, iceplants are able to stabilize soils and dunes and prevent erosion incredibly well. They performed so well that the California Department of Transportation company Caltrans decided to plant thousands of acres of iceplants along roadsides and highways throughout the state until the 1970s. The plant became so associated with the company that it was even named the CalTrans plant at one point. This is also why iceplants are called highway plants! While the plant itself does an incredible job at preventing soil erosion and stabilizing soils, it harms coastal dune habitats in California’s beaches by creating giant slopes of sand, which prevents native coastal dune plants from growing on sand. The absence of native plant species on sand dunes is problematic because these plants are at the base of the ecosystem, offering food and shelter to important pollinators and animals.
Different varieties of iceplant can be more common in different habitats. Below are 8 different varieties of iceplants found in Orange County.
Pictured above is Carpobrotus edulis, also known as the iceplant, the hottentot fig, or the highway plant. This variety can have yellow or pink flowers, and succulent green leaves that are typically hairless.
Pictured above is Carpobrotus chilensis, also known as iceplant or sea fig. This variety is often confused with Carpobrotus edulis and is commonly found in coastal scrub habitats, dunes and beaches. This variety has pink leaves with succulent green leaves. This variety also breeds with Carpobrotus edulis to make hybrids.
Carpobrotus chilensis can be distinguished from Carpobrotus edulis through its leaves, which are completely smooth. Carpobrotus edulis has slightly serrated edges on its leaves. Carpobrotus chilensis also does not have a stem on its flower, while Carpobrotus edulis has a very short stem.
Pictured above is Mesembryanthemum crystallinum, also known as crystalline iceplant or the common iceplant. This variety blooms white flowers and has crystalline vesicles over its red and green leaves and stems that accumulate salt, preventing other plants from growing near it.
Pictured above is Drosanthemum floribundum, also known as the Rodondo creeper, or iceplant. This variety has silver-gray leaves with pink flowers and crystalline vesicles on its leaves and stems.
Pictured above is Malephora crocea, also known as coppery Mesembyrnthemum, or red iceplant. This variety has red flowers and narrow green leaves.
Pictured above is Malephora luteola, also known as the Rocky Point iceplant, or the yellow iceplant. This variety has yellow flowers and shorter succulent leaves.
Picture above is Mesembryanthemum nodiforum, also known as the slenderleaf iceplant, or the small flowered iceplant. This variety has white and yellow flowers with short and narrow red and green leaves, more commonly found in wetlands and dunes.
Pictured above is Aptenia cordifolia, also known as red apple, baby sun rose, dew plant, and heartleaf iceplant. This variety has small, heart-shaped green leaves with small red, pink, or purple flowers.
While iceplants do not offer many ecosystem services, they are edible! Both the leaves and stems are edible, and according to Edible Wild Food, the leaves of iceplants can even be pickled.
One easy way to prevent the spread of this invasive species is to not buy iceplants from nurseries. These are commonly used plants in landscaping throughout the entire county, and humans have proven to be helpful in expanding this plant’s distribution. According to the California Department of Fish and Wildlife, planting native plants, such as purple sage, as an alternative to iceplant is also an effective way to promote native biodiversity while preventing soil erosion and maintaining beautiful gardens and landscapes in Orange County. Another way to address this invasive species is by manually removing them. Because of their shallow roots, iceplants are easy to hand pull, and there are many volunteer opportunities to remove this invasive species that anyone can sign up for. OC Habitats holds ecological restoration events that involve iceplant removal, and if you’d like to have a hand in doing incredible work for your environment, you can sign up on our EventBrite page!