Ice plant (Carpobrotus edulis) is a succulent native to South Africa, but common in chaparral habitats around the world. Though it was once grown in California, Australia, the Mediterranean, and similar areas as a decorative plant, it has become an invasive species and a threat to native vegetation. This plant is hardy and quick to reproduce, easily growing into a thick ground cover that chokes out other plant life and depletes soil nutrients. The only reliable way to control ice plants are to uproot them physically.
An ice plant is attractive, with fleshy green leaves covered with small fibers, causing them to sparkle like ice in the sun. It also features bright yellow, pink, or white flowers and edible fruit that is made into jam in South Africa. The leaves sometimes turn red or yellow. This plant was first introduced to California in the early 20th century, when it was used to stabilize soil along railroad tracks. It also became a popular garden plant, and some continue to grow it for decorative purposes today.
Despite the beauty of ice plant, it has become an ecological nuisance in California and other areas in which it is not native. it has proliferated along California highways to the detriment of many native species. It dominates the areas where it grows, resulting in very low biodiversity and depriving other species of the resources they need to grow, such as soil and space. Ice plants reproduce both through fruit, which is produced year round, and through segmentation, meaning that any shoot can put down roots. A single shoot can grow 3 feet (about 1 meter) in a year.
A chemical herbicide is used in California to control ice plants, but it is not completely effective. Completely removing the plants, along with their root systems, is the best way to excise ice plant from an area, though it is labor intensive and time consuming. After all parts of the plant are removed, the soil must be mulched to prevent recolonization.
Though ice plant is an invasive species, it requires very specific conditions to grow and will not expand outside of chaparral areas. It tends not to grow above elevations of 500 feet (150 meters) and cannot tolerate frost.