The thing on top of a moon cactus is actually the scion, which is the colorful and eye-catching part of the plant. The scion is typically red, orange, or yellow in color and is the result of grafting Gymnocalycium mihanovichii onto a green cactus host.
Grafting is a process where two different plants are joined together to create a new plant with desirable characteristics. In the case of the moon cactus, the scion is the desired part because of its vibrant colors, while the green cactus host serves as a rootstock to provide nutrients and support to the scion.
The scion, Gymnocalycium mihanovichii, is a small cactus native to South America. It has a distinctive globular shape and lacks spines or areoles, giving it a unique appearance. The scion is often referred to as the “moon cactus” or “ruby ball cactus” due to its round shape and bright colors reminiscent of a full moon or a precious gemstone.
The green cactus host that forms the lower part of the moon cactus can vary in species but is commonly a Hylocereus cactus. This cactus provides the necessary root system for the scion to grow and thrive. The green cactus host is typically taller and larger in size compared to the scion, serving as a stable base for the grafted plant.
The reason moon cacti are almost always grown as potted plants rather than garden specimens is because the scion, Gymnocalycium mihanovichii, is actually a mutant cactus that lacks the ability to produce chlorophyll. Chlorophyll is essential for photosynthesis, the process by which plants convert sunlight into energy. Without chlorophyll, the scion cannot survive on its own and relies on the green cactus host for sustenance.
Growing moon cacti in pots allows for easy control of their growing conditions, such as providing adequate sunlight and water. These plants thrive in bright, indirect light and require minimal watering. Overwatering can lead to root rot, while insufficient light can cause the scion to lose its vibrant colors.
In my personal experience, moon cacti make fantastic indoor plants, adding a pop of color and interest to any space. They are relatively low-maintenance and can be a great choice for those who may not have a green thumb. I have found that placing them near a sunny window or under a grow light helps maintain their colorful appearance.
To summarize, the thing on top of a moon cactus is the scion, which is a Gymnocalycium mihanovichii cactus grafted onto a green cactus host. The scion is the colorful part of the plant, while the green cactus host provides support and nutrients. Moon cacti are best grown as potted plants due to the scion’s inability to produce chlorophyll. With proper care, they can be a stunning addition to any indoor space.
