Moon cactus
Gymnocalycium mihanovichii
Also called Ruby ball and Grafted cactus
Houseplant · Succulents & cactiTwo plants, not one. The coloured ball has no chlorophyll and cannot live alone — when the green stock below it goes, so does the top.
Care at a glance
- Ease
- Medium
- Water
- Every 16 daysSoak, then bone-dry — wait until the soil is dry right through — lift the pot, it tells you.
- Light
- Bright indirect, not harsh sun
- Feed
- Every 60 days
- Humidity
- Low
- Hardiness
- Indoors, or out in high summer RHS H1B, to 10°C
- Size
- 0.25 m tall · 0.1 m across
- Lifecycle
- Perennial
- Origin
- Grafted — Paraguay and Argentina
Is it safe for pets and people?
PetsNothing recorded against it
No animal-poison authority lists this plant either way.
PeopleNot checked yet
Nobody has checked this one against a source for us yet, so treat it as unknown rather than safe.
Checked against ASPCA and RHS on 2026-07-31. Where a source says nothing, we say nothing.
A guide, not veterinary or medical advice. If a pet or a person has eaten a plant and you are worried, call your vet or doctor now — don’t wait for signs to appear. Spotted a mistake? Tell us.
First signs of trouble
- The green stock below the join shrivels and goes corky while the coloured head above it still looks perfectly well.Graft failure · disorder