Why Your Moon Cactus is Losing Color?


Moon cactus is composed of a spherical cactus in various vibrant hues, commonly in red, pink, yellow, orange, and sometimes purplish-black, sitting on the top of another green base cactus. These bright color ball-shaped cacti can sometimes surprise you by changing their color.

Moon cactus lose their color when their growing condition is not ideal. There are four reasons why moon cactus change their color over time: 1) light exposure, 2) insufficient nutrients, 3) overwatering, and 4) old age. These factors may cause death to the plant if left unsolved.

Unlike other cacti, the pure variegated moon cactus spherical head is short-lived and has to be grafted onto another cactus to survive. Although they need little attention, giving them proper care will save you from future problems like fading or losing color. Let’s look deeper and know more about the reasons behind their color change.

Why Do Moon Cactus Lose Their Color?

Gymnocalycium mihanovichii, also known as ‘Hibotan’ or ‘Ruby Ball,’ is the top graft section of a moon cactus. This is a mutant plant with almost no chlorophyll, a green pigment responsible for the absorption of energy from sunlight needed by plants to make their food through photosynthesis. This mutant plant cannot survive on its own.

The first cultured cultivar is called ‘Hibotan’ with an orange to red hue. E. Watanabe, a nursery keeper in Japan, discovered this cactus. ‘Hibotan’ has some specks of green in their body. Since it is a mutant cultivar, many clones were obtained, including pure neon pink, dark purple, orange, yellow, and sometimes two-toned yellow and red.

Moon cactus is a combination of two different cacti grafted together. The top cactus or the ‘scion’ is the ‘Hibotan’ cactus, while the bottom cactus or the ‘rootstock’ is any cactus species. A Hylocereus species is the common rootstock used. The diameter of the cactus ball on top usually measures 3-6 centimeters. They have 8 – 10 noticeable ribs around their body with narrow edges.

The top cactus is dependent on the cactus it sits upon because the rootstock is the source of nutrients it needs to survive. Technically, the term ‘moon cactus’ only refers to the orange and yellow clones. Moon cactus has the highest demand among the cactus available in the market. Korea has the largest grafting industry and imports over 10 million grafted cactus over a year.

The original vibrant color of Moon Cactus

4 Reasons That Affect Color Fading in Moon Cactus

Healthy moon cactus appears to have a vibrant scion color and a healthy green rootstock. A color change might not immediately pose a danger to your plant. Nonetheless, usually, color change in a moon cactus can be a sign of an underlying problem. There are several reasons associated with fading or color loss in the moon cactus.

Sometime during 2005, Korean scientists developed a new cultivar of moon cactus called ‘Hwangseon’. They cross-pollinate 2 different moon cactus cultivars, which are the ‘Geoseong’ and ‘Huhwang’, both orange colored. They made a series of selection trials and the final selection was obtained in 2009. The new cultivar was registered as ‘ Hwangseon’ in early 2010. The Gymnocalycium Mihanovichii cv. ‘Hwangseon’ has a bright yellow color and is flat round in shape.

Light Exposure

You noticed that your moon cactus is gradually losing its vibrant glow and becomes pale or have patches. Sun exposure can be a contributing factor to this problem. Although the top graft can tolerate low light and survive under a shade, the green rootstock needs ample sunlight to grow well and support both (itself and ball graft) their needs.

Keeping your plant in the shade for an extended period can weaken the rootstock, while over-exposure to the sun can damage the top cactus. Sudden, prolonged sun exposure can get your moon cactus a sunburn which appears to be brown patches on your plant. However, gradually introducing your cactus to direct sunlight will make them adaptive to the condition. The more they bask in the sun, the more they become vibrant. It is just a matter of adaptation.

Old Age

Moon cacti usually don’t last long. On average, a moon cactus can survive between 1-4 years maximum. However, there are some adept growers who went beyond that expected span of years. Moon Cactus have a shorter lifespan due to the top cactus outgrowing the rootstock and sucking all the nutrients until the bottom cactus cannot provide anymore. When the old rootstock becomes too weak and thin, chances are it cannot transport sufficient nutrients to the ball graft, leaving it pale and unhealthy.

The best way to save the top graft is to remove it from the dying rootstock and re-graft it to another healthy cactus to continue its life span. Another problem with the aging moon cactus is corking. It is a natural phenomenon that occurs as the moon cactus ages. The plant will develop brown colored patches of skin that are hard to touch.

Over Watering

Like other cacti, the moon cactus is also drought-resistant and requires a minimal amount of water to thrive. Overwatering your moon cactus will result in root rot, where it becomes mushy and yellow and can spread upwards, damaging the top cactus.

Insufficient Nutrients

Moon cactus do not need feeding often. But underfeeding them will deprive them of the nutrients that they need, resulting in unhealthy pale plants. Nutrient-rich, good quality, and gritty potting mix will work best for your moon cactus. Feeding them the nutrients they need during their active state can boost their chance of survival.

Moon Cactus Loosing Color – Infographic

How To Prevent The Moon Cactus From Fading: 3 Tips

Moon cactus is not very difficult to grow and requires little of your attention. Although the scion and the rootstock have different growth rates, providing them a balanced environment will keep them both thriving. They are low-maintenance plants that add beauty and color to your balcony or garden. You can maintain their vibrant colors for a longer time, given the proper care and cultivation needs. Read on to know more about moon cactus care.

Indirect Sunlight and No Cold

Moon cactus can thrive in warm temperatures but cannot survive cold drafts. Temperatures below 48.2°F (9°C) can be harmful to them. Moon cactus should never be left outdoors in winter, if not in a very mild climate.

The two cacti that make up a moon cactus have different light preferences. While the bottom green cactus loves direct sunlight, the colorful one on top cannot tolerate intense direct sunlight. To keep them both thriving and maintain their good appearance, make sure they can get enough sunlight their system needs. It is best to place them in a bright spot away from direct sunlight.

Soak and Dry Technique

The best method of watering your moon cactus is to soak and dry. Meaning, before you water your plant, make sure that the potting mix is almost dry. You can tell that your plant needs watering by simply lifting the pot. Lightweight pot indicates dry potting mix.

Pour enough water into the soil, soaking up the whole pot until the water drains out at the bottom. Let the potting mix dry out thoroughly before you water again. You can do this once a week or twice if it gets warmer in your area. The frequency of watering your cactus also depends on your potting mix. The ideal potting medium for cactus is gritty and well-draining. This way, you can avoid over/under watering your cactus.

No Feeding When Dormant

Feeding your moon cactus, especially during the growing season around April to December, is essential for healthier, vibrant colored plants. Skip feeding them during the dormant season.

Is My Moon Cactus Dying Because Of Color Change?

Moon cactus are resilient and can thrive with minimal care. A change of color in the moon cactus does not generally mean that it is dying. You need to observe the change and determine the conditions that might have triggered such a change. If your cactus turns yellow, soft to touch, and emits a foul odor, then you should take immediate steps to save it from dying. But if the plant appears to be all healthy and in good condition despite the color change, then you should not worry too much.

Sometimes a change of color in a moon cactus can be a sign of good health. Let us say that you gradually exposed your plant to intense light, and it gets even more vibrant and healthier, then it’s a good sign that your plant has adapted to the condition. However, suppose the case of your moon cactus is severe discoloration (yellow and brown) accompanied by mushy tissues and rot root caused by overwatering. In that case, it is a sign of a dying cactus.

You can however save the part that is not affected by discoloration. Suppose the rootstock turns brown at the base, you can save the remaining plant by cutting off the damaged part. Wait till the cut is calloused and healed before replanting.

Discolored moon cactus can recover depending on the severity of the damage. Moon cactus scion that is severely scorched has no way of bouncing back. But the rootstock, that if it is still green, needs some saving by de-grafting or removing the sunburnt scion. Allow the top cut to heal and callous. Rootstock that is yellow and mushy from the base up to the scion cannot be redeemed. The scion however can be saved if it is not affected by rotting rootstock. It can be re-grafted to another new rootstock to extend its life span.

Other Factors Affecting Color Change in Moon Cactus

Color change in the moon cactus happens gradually. They don’t just happen overnight, and the last thing you know, the damage is already done. For moon cactus, too much and too little can harm them.

Moon cacti fading due to root rot and sunburn.

Sunburn

Sunlight is essential in photosynthesis that helps plants to make their food. Every plant has a limitation on how much sunlight they need. Over exposing a moon cactus to intense light that they cannot handle is not helpful for them. Instead, it will cause an adverse effect until you take action to save your moon cactus. Sunburn damages the skin of your plant, turning its color from pale to brown.

Lack Of Water

Dehydrated moon cactus tend to shrink and wrinkle, and the once vibrant color will turn dull or pale. They wither due to an insufficient supply of water in their system. Their appearance becomes dry because they have used up all the water they stored in their body.

Does The Texture of The Cactus Change?

When the top and the base cactus lose their color due to overexposure to sun and dehydration, their body becomes stiff and crisp. You can still save the plant, given this scenario. However, if the case involves over watering accompanied with root rot and fungal infection, the consistency of the affected part becomes tender, wobbly, and mushy. These are signs of a dying moon cactus.

Takeaways

  1. Moon cactus colors tend to change their color due to some contributing factors like sun exposure, water supply, aging, and fertilization.
  2. To save your plant from losing color or fading, give them their essential requirement, and they’ll reward you with vibrant colors to brighten your day.
  3. Though resilient and easy to grow, Moon cactus are still vulnerable to death if the condition is unsuitable.

Sources

“A History Of Grafting,” Ken Mudge, Dept. Of Horticulture, Cornell University

“Photosynthesis,”Estrella Mountain

Grafted Cactus, Neon Cacti, Moon Cactus, Hibotan Cactus, Division of Agriculture, University of Arkansas

“A New Grafted Cactus with Bright Yellow Color, ‘Hwangseon’, Korean Horticultural Science

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Esther

Esther is the self-proclaimed cactusholic :D of the team. She owns a cacti shop with hundreds of plants that she takes care of. Esther has many years of experience in growing and caring for drought-resistant plants like cacti and succulents.

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