When I first saw a “Moon Cactus” as a youth, I was fascinated and perplexed at this almost artificial looking creation. I only knew that I wanted one and that was it. Over the years the “Moon Cactus” or “Neon Cactus” have remained a standard fare at almost every garden center as a curiosity and novel horticultural wonder. How did this succulent come into existence?
The origin story of the Moon cactus goes back to the late 1930’s/early 1940’s when a Japanese nurseryman grew a type of cactus called Gymnocalycium mihanovichii or chin cactus. Some had mutated to sport bright colors of yellow, orange, red, and pink. As these mutations had no chlorophyll, they could not exist on their own roots and had to be grafted onto a host cactus. This host cactus – Hylocerus undatus – is the triangle shaped, green “trunk” that you see as the stock. This union of the scion – the top colorful cactus, with the green root stock, offers a compatible combination that works where the green portion supplies the chlorophyll-lacking, colorful topknot. So, while “manmade”, it solved a survival problem in a unique horticultural manner. There are about sixteen color variations recognized. Interestingly enough, a majority of Moon cactus production comes from South Korea.
While many succulents and cacti like full sun locations, the Moon cactus prefers bright, indirect light – full sun will actually cause sunburn. Keep Moon cactus in any well-drained cactus soil mix and let it dry out between waterings. Like other succulents, keep these plants on the dry side during winter months and bring them indoors if the temperatures drop below fifty degrees F. Water and feed your Moon cactus with dilute fertilizer during the growing season.
You will find that Moon cactus will develop numerous offsets as they grow which can be used to propagate new ones. As mentioned above, successful propagation involves grafting the Moon cactus offset onto a new rooted host most notably Hylocerus undatus. Without going into too much detail here – you can find plenty of how-to videos online – the top section scion base is cut to match and connect to the bottom rootstock portion so that the cut tissue comes together and is kept in place until the wounds seal and the tissues connect and seal up. I have seen various methods including the use of rubber bands and fishing weights crisscrossed over the top of the Moon cactus to gently, but firmly apply pressure to the two pieces until they are sealed and structurally sound. Grafting is an art and science, so you may have to practice this a bit.
Bottom-line, Moon cacti are colorful and interesting novelties that make great gifts for the gardener who has everything. They are normally readily available at most garden centers in colors sure to please. Enjoy Moon cactus – neon color, prickly nature! For more information on succulents, or to ask a question, you can also call the Master Gardener Volunteer Helpdesk on Mondays, Wednesdays, and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Ralph E. Mitchell is the Director/Horticulture Agent for UF/IFAS Extension Charlotte County. He can be reached at 941-764-4344 or ralph.mitchell@charlottecountyfl.gov. Connect with us on social media. Like us on Facebook @CharlotteCountyExtension and follow us on Instagram @ifascharco.
Resources:
Plant of the Week: Grafted Cactus, Neon Cacti, Moon Cactus, Hibotan Cactus (2024) The Cooperative Extension Service is part of the University of Arkansas System Division.
Gymnocalycium mihanovichii (2024) N.C. Cooperative Extension – North Carolina Extension Gardener Plant Toolbox.
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