Gymnocalycium

( jim - noh - kaly - LIS - ee - um )

At-A-Glance Information

Commonly called Chin Cactus, this genus of cacti includes species that are mostly native to South America. These are low-growing, with globular short stems. They are green and their surfaces are somewhat depressed in areas. They produce spines that curve back against the body, and are considered easy to flower. These cacti do well in bright, indirect sunlight with a preference for morning sun. Use these versatile succulents in rock gardens, containers, or as a low-growing border edge.

Gymnocalycium Species and Varietals

The genus Gymnocalycium includes 70 species of cacti, and is a member of the plant family Cactaceae. Species are closely related to those in the Echinopsis genus. The genus name is derived from the Greek term for 'naked calyx'. Gymnocalycium cacti grow best in USDA hardiness zones 9a-11b. To find your zone, click here: Zone Map.

Gymnocalycium amerhouseri (Chin Cactus)
Native to Argentina, this rare species of cacti is dark green to blue-green. Flowers are white with pinkish red centers, and spines are white. Fruits that follow flowers are egg-shaped and dark green. The species is named for Austrian cactus connoisseur Helmut Amerhauser. Very slow-growing.

Gymnocalycium mihanovichii (Moon Cactus, Chin Cactus, Plaid Cactus)
This species, native to South America, is most commonly seen in mutated variants which completely lack chlorophyll, exposing red, orange, or yellow pigmentation. These mutations, unable to survive on their own, are commonly grafted onto Dragon Fruit plants to survive.

'Black Widow'
With a reddish-black body.

'Friedrichii'
Also called Purple Moon Cactus, with deep purple-brown bodies.

'Hibotan'
This is the most common cultivar, and has a red, pink, or orange body.

'Nishiki'
Variegated form highlighting black and red.

Gymnocalycium mostii
This solitary cactus forms a dark green flattened spherical stem to up to 3 inches tall at maturity. Spines are long and recurved, and flowers are white with pink lines. Fruits that follow are egg-shaped and slate to blue-green. This species is native to Argentina.

Gymnocalycium quehlianum (Quehla Chin Cactus)
This species of cacti is native to northern Argentina and typically grows as a solitary stem but can form groups. They are green with recurved spines, and produce white flowers with red throats. Individual plants reach up to 6 inches tall when mature. These are typically cultivated in pots, and must be kept in a greenhouse or other sheltered space where temperatures fall below 50 degrees Fahrenheit.

Gymnocalycium saglionis (Giant Chin Cactus)
Endemic to northwestern Argentina, this species of cacti grows very slowly and has a preference for shaded conditions. It can range in color from dull green to blue-green, and reaches up to 35 inches tall and 16 inches wide when mature. Spines contrast well, and flowers are white to reddish.

Caring for Gymnocalycium

Plant Gymnocalycium, or Chin Cactus, in a space in the landscape that receives full sun to partial shade; ideally, they appreciate between 4 and 6 hours of sun each day for the best overall growth and plant health, and prefer morning light over afternoon sun. Ensure that soil is very well-draining and has a pH of between 6.0 and 7.0 (slightly acidic to neutral). Chin Cacti like a soil that is amended with plenty of sand and perlite to improve drainage. Apply a layer of rock mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention.

These Cacti appreciate a 'soak and dry' watering method. Water thoroughly when the soil is completely dried out during the growing season in spring and summertime (typically every 10 to 14 days). When plants are dormant in fall and winter, they should not be watered. These Cacti do not need to be fertilized, and rarely need pruning, as they are low-maintenance, slow-growing, and maintain their shape naturally; they typically thrive on neglect. Pruning is only necessary to remove dead or diseased sections due to root or crown rot. Damaged spines and spent flowers can be removed at any time during the growing season (spring or summertime). Avoid cutting into healthy, green flesh as this can damage the plant and invite insect and disease to take hold. Gymnocalycium plants are long-lived perennials, able to survive in the landscape for between 10 to 30 years before needing to be replaced. A notable exception are the chlorophyll-less mutations of Moon Cacti, or Gymnocalycium mihanovichii, which when grafted have a life expectancy of just 1 to 3 years.

Caring for Gymnocalycium in Containers
Chin Cacti are wonderful in the ground, but can also be grown in containers. This allows for growers in cooler climates to care for these warm-weather plants. Choose a pot that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a dry, very well-draining soil (peat amended with plenty of sand and perlite is typically sufficient), and top with a layer of rock mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Place the container in a space that receives partial sun. These cacti appreciate a 'soak and dry' watering method. Water thoroughly when the soil is completely dried out during the growing season in spring and summertime. When plants are dormant in fall and winter, they should not be watered.

They do not need to be fertilized, and rarely need pruning, as they are low-maintenance, slow-growing, and maintain their shape naturally. They typically thrive on neglect. Pruning is only necessary to remove dead or diseased sections due to root or crown rot. Damaged spines and spent flowers can be removed at any time during the growing season (spring or summertime). Avoid cutting into healthy, green flesh as this can damage the plant and invite insect and disease to take hold. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

There are two main ways to propagate Gymnocalycium: by offset and by seed. The easiest way is through offset because it requires little disruption to the parent plant and ensures that you will get an exact clone, which is something not guaranteed by the seed propagation method. Peruse the propagation methods for Chin Cacti below:

Propagating Gymnocalycium by Division
The easiest way to propagate Gymnocalycium is by identifying and removing offsets and replanting them. To propagate your these cacti by offset, you'll need a clean trowel and a pot filled with soil half amended with gritty sand (or filled with cactus/succulent mix). Once you've gathered your materials, follow these steps:

Loosen the soil around the bottom of the cacti where the offset has formed and locate its connection to the parent plant. Cut it from the parent plant with a sharp, clean trowel or knife. Take care to not damage the offset or the parent plant during this process.
Then, place the offset in a shaded, dry area that receives good ventilation for a few days until it forms a callous where it was cut from the parent plant.
Plant your offset in a pot filled with potting mix and lightly moisten the soil, ensuring that adequate drainage is occurring. Place the container in an area that receives bright light and stays relatively warm.
Water every time the top inch or two of soil dry out, but don't saturate the soil. After a few weeks of this watering schedule, the offset should be ready to be planted outside in its permanent home. Then, follow the instructions in the care section to grow your offset into an adult plant.

Propagating Gymnocalycium by Seed

Gather your materials and fill your pot with potting mix amended with plenty of sand and perlite (to increase drainage). Place the seeds on top of the soil about a centimeter apart, and cover them with a layer of coarse sand.
Water the seeds, being careful to not disturb their placement under the sand. Keep the seeds moist but not wet as they germinate, which should happen in 1 to 4 weeks' time. The pot or tray should be in an area that receives bright indirect light. It is important to attempt to germinate more than a few seeds, as it is likely that not all seeds will germinate successfully.
After most of the seeds have germinated, increase ventilation and provide the seedlings with good light, but not direct sunlight. About five weeks after germination, cut watering to about once a week, allowing the soil to dry out in between waterings. Do not provide water if the soil is still moist.
Harden off seedlings by placing them outdoors for increasing amounts of time over a few weeks so that they do not experience transplant shock when they are planted in their forever home outdoors. Once established in the landscape, return to regular care guidelines above.