Interestingly enough, these unique plants don’t produce their own chlorophyll, and they have to be “grafted” onto another plant to survive. So when you spot a moon cactus in the store, it’s actually two plants in one. Whether you’ve purchased a moon cactus or you’re looking to grow one yourself, here’s everything you need to know. It’s a grafted cactus, which, according to Debra Lee Baldwin, author of Succulents Simplified, means a plant that has been attached to a host plant. The top part of a moon plant is unable to photosynthesize, aka make energy from sunlight, due to a lack of chlorophyll. “Grafting enables its vascular system to obtain nutrients from a host plant,” Baldwin explains, adding that “grafted cactuses tend to be less hardy than those that grow on their own roots, but sometimes grafting is the only way to keep a desirable specimen going.” Because these plants have a hard time living on their own, Baldwin notes they typically last for only six months to a year—if you’re lucky. “It’s sort of set up for failure,” she tells mbg. “The green part, which looks like a stem, needs sunlight. The top part can’t tolerate direct sun because it lacks protective pigment.” “Keep in bright shade with one or two hours of slanted sunlight (morning or afternoon) daily, depending on where you live,” Baldwin suggests. If you live somewhere with intense sunlight, she adds, you’ll need to make sure your moon cactus doesn’t get sunburn—yes, really. If your plant is showing beige patches, it’s likely sunburned. The lighting factor can be tricky since the top part is sensitive to light, while the host cactus still requires it. Moon cactuses also don’t do well in the cold, as you’d probably imagine, and need to be kept in a space that’s relatively warm and definitely protected from frost, Baldwin adds. And just as an FYI, even with all the right amounts of sunlight and water, “moon cactuses are not known to grow much, if at all,” she says. During the winter months, your moon cactus may need to be watered even less frequently, especially if it’s over a year old. This succulent watering guide will tell you how to discern when your little guy is thirsty. As with all plants, it’s a good idea to put your moon cactus in a pot with drainage holes, to prevent moisture buildup and root rot. To do this, use a clean knife to cut off the top piece (or “scion”) you want to propagate, and then, using a healthy, rooted cactus (such as any of the aforementioned varieties), cut off the top so it’s only about a few inches tall. Set the offshoot on the top of your new rootstock where it was cut. From there, you can hold them together with rubber bands or string. Vertically wrap it all the way around your plant and pot to keep everything in place. In six to eight weeks, your plants should be growing together as one! Just be sure to keep an eye out for any rot or pests in that time. Nevertheless, they make a fun addition to any succulent collection, and if you’re looking for a pop of color, minimal watering requirements, and a unique “mutant” plant, a moon cactus might just be the perfect fit for you, albeit temporarily.
