This plant is quite iconic to the California Coast; along highways you see bright green carpets stretching wide next to the glistening ocean. You often see spots of hot pink, yellow or even purple as these flowers bloom. While the view may be lovely, their impact on our California dune ecosystems does not have the same effect.
Carpobrotus, otherwise known as ice plant, is essentially an extensive weed in our dunes. You can find it in many of our parks, often right up to the edge of cliffs. If you decided to get up close and personal with it, you would notice it has succulent leaves that point straight up into the air like little columns. Rather than growing like a bush, ice plant likes to grow low to the ground, with horizontal branches that intertwine themselves into large mats.
If ice plant grows well in California and looks so pretty, why is it even a problem? Plus, if you read my previous blog, it’s so difficult for plants to grow on dunes, so shouldn’t we be happy something is growing there? Well, as you may notice that in areas with ice plant, it is often the only plant there. This is because it is an invasive species.
Ice plant originates from South Africa, and was brought to California in the early 1900s. It was used to stabilize soil along railroad tracks, and now we see it along highways stabilizing soils there. As an invasive species, ice plant spread like wildfire into our dune plant communities. In areas where there could normally be up to 10 native species, we only see ice plant. This greatly reduces the diversity of our dunes and puts native plants at risk of losing their already scarce habitat.
Although ice plant is supposed to help stabilize the soil, it’s actually pretty bad at that as well. With shallow roots and branches climbing over each other, it can become very heavy. This causes large mats of the ice plant to fall off of steep surfaces at once, taking nutrients and topsoil along with it.
Ice plant has become a widespread problem in our local dunes and is very hard to control. When approaching the removal of an invasive species, or any species, you can use means of biological, manual or mechanical, and chemical control. There is currently no biological way to remove ice plant, and burning it is an ineffective method because of the plant’s high water content.
The most effective way to get rid of it is through manual or mechanical removal, which is literally pulling and removing the plant completely from the area. The plant can re-sprout from any segment, so all debris must be removed.
A chemical control herbicide called glyphosate has also been found to be effective, but one should always be weary of using chemical methods near native vegetation and water sources. Both methods will take years of monitoring and follow up removal to completely rid the area of ice plant.
The fight against ice plant has already begun, but we have a long way to go! If we work together, we can try to attempt to restore our beautiful native dunes.