By Lauren Lewis
If you’re someone who notices the plants around you (you know it if you are!), you’ve probably noticed that people love their succulents. These fleshy desert plants have become hugely popular for landscaping, indoor plant collections, party favors, etc over the last couple decades. And with good reason because they are hardy plants, drought-tolerant, and visually eclectic and striking. Several interesting adaptations have made succulents a strong candidate for the increasingly-dry California garden.
If you were to describe the look of a succulent, the primary adjective might be something like plump, or fleshy; essentially, full of water. Succulents store water to a much greater extent than other plants because they evolved in dry environments- storing more water when it is available means they can survive through dry periods on the stored water. In addition to storing water they also need to minimize water loss, so they use a form of photosynthesis called CAM (Crassulacean acid metabolism), which is not used by all the flatter-leafed plants.
Here’s how it works: the plant keeps its stomata (holes to the outside) closed during the day to minimize lost water from transpiration, but opens them at night, when it’s cooler. Carbon dioxide is therefore only absorbed at night, through the open stomata, and is converted into a storable form and stored in the vacuoles (the water storage part of a plant cell). Then during the day, when the plant is receiving sunlight, the plant uses the stored CO2 and water to perform photosynthesis. A non-CAM plant could absorb CO2 and perform photosynthesis all at once, during the day, but a CAM plant doesn’t have that luxury due to the high heat outside.
So succulents have evolved extra complicated chemical pathways, as well as various other water-focused adaptations I haven’t mentioned, that make them very useful for gardening in an increasingly hot and dry environment. But that’s not all! They are also especially easy to propagate. When we visit our gardens for routine care, we routinely take cuttings of all sizes from mature succulents, and plant the cuttings right away another place in the garden. The cuttings almost always establish themselves easily, and we’re filling out the garden without buying new plants. If you look around online, succulent propagation guides recommend letting the cuttings (which can be as small as a single leaf) dry out before planting, so they don’t absorb too much water when planted, but we’ve had success both ways.