Light
Filtered Sun
Avoid harsh, direct sunlight; bright, filtered or indirect light is best.
Reference image 
Reference image Frailea schilinzkyana
Schilinzky's Frailea
Overview
Frailea schilinzkyana is a remarkably small-sized, usually solitary cactus species in the family Cactaceae. Known for its extremely compact growth and fascinating cleistogamous flowers, this miniature cactus is highly sought after by succulent collectors 1.
Taxonomy and Naming
The genus Frailea was named in honor of Albert Manuel Pratt Fraile, who was a curator of the United States Department of Agriculture's collections. The specific epithet 'schilinzkyana' commemorates Schilinzky, a notable cactus enthusiast 2. It belongs to a group of dwarf cacti adapted to shrinking into the soil during dry seasons.
Distribution and Habitat
This species is native to southern South America, including southern Brazil (Rio Grande do Sul), Paraguay, Uruguay, and northeastern Argentina 3. It thrives in subtropical grasslands, rocky outcrops, and shallow soils where it is often sheltered by surrounding vegetation.
Appearance
The stem is globose to depressed-globose, usually dark green to brownish-purple, and rarely exceeds 3-4 centimeters in diameter. It features 10 to 13 low, tuberculate ribs. Spines are short, fine, and pressed against the stem. The yellow flowers often produce seeds cleistogamically, meaning they self-pollinate without ever fully opening 12.
Cultivation
In cultivation, it requires an extremely porous, mineral-based substrate. Watering should be regular but careful during summer, and completely suspended in winter. Filtered sunlight or partial shade is crucial to prevent sunburn and to help maintain its beautiful, dark epidermis 3.
Common Mistakes
The most frequent error is overwatering combined with poorly draining soil, which rapidly leads to root and stem rot. Additionally, exposing the plant to intense, direct afternoon sun can cause irreversible scarring.
References
Watering
10-30 Days
Allow soil to dry fully between waterings; keep bone-dry in winter.
Soil
Slightly acidic, highly porous cactus mix rich in pumice and coarse sand
Use a highly gritty, fast-draining cactus mix with plenty of pumice.
Safety
Pet Friendly
Non-toxic and safe around cats, dogs, and children.
Difficulty
Moderate
Requires moderate care due to its miniature size and sensitivity to overwatering.
Native Habitat
South America
Naturally distributed across the subtropical grasslands, rocky ledges, and thin soils of southern Brazil, Paraguay, Uruguay, and northeastern Argentina.
Frequently Asked Questions
How large does Frailea schilinzkyana grow?
This species is miniature, with the stem diameter rarely exceeding 3-4 centimeters.
Is it toxic to pets?
No, Frailea schilinzkyana is non-toxic and completely safe for cats and dogs.
Why do the flowers produce seeds without opening?
This plant is cleistogamous, meaning it self-pollinates and produces seeds without the flowers ever having to open.
How often should I water it?
Water it only after the soil dries completely (about every 10 days in summer) and keep it dry during winter.
What kind of pot should I choose?
Since its root system is small, shallow pots with drainage holes at the bottom are highly recommended.
What temperature should it be kept at in winter?
During winter dormancy, it is ideal to keep it dry at temperatures between 5°C and 10°C.
Can direct sunlight harm it?
Yes, intense and direct summer sunlight can cause sunburn scars. Filtered light is recommended.
What type of soil does it need?
It needs a highly porous cactus mix rich in pumice, lava rock, and coarse sand for excellent drainage.
How fast does it grow?
It is a very slow-growing cactus, taking several years to reach its mature miniature size.
Is it easy to grow from seed?
Yes, the self-produced seeds are fresh and usually have a high germination rate in a proper cactus seed-starting mix.