Plate No. 31

Living Rock

Ariocarpus fissuratus

"A grey pebble that flowers in autumn"

Native to

Chihuahuan Desert of Texas and northern Mexico

Botanical illustration of Living Rock
Ariocarpus fissuratus — drawn from life
History

A brief account

So perfectly disguised as cracked limestone that even botanists have walked past it. The Tarahumara call it hikuli sunami and consider it sacred. In late autumn it opens a magenta or white flower from the woolly crown, entirely without warning.

How to care for

Living Rock (Ariocarpus fissuratus) grows best when its natural cycle of strong light, freely draining soil and measured watering is respected. Give it full sun. Water it according to its seasonal needs: almost none — a monthly light misting in summer; nothing else. Plant it in pure mineral: pumice, gravel and limestone chips. A container with an unobstructed drainage hole is essential, because moisture lingering around cactus roots can quickly lead to rot. Keep its temperature needs in mind: -5 to 40°c. cold-hardy when dry. During active growth, check the compost before watering rather than following a rigid calendar, since heat, light and pot size all change how quickly it dries. Reduce watering during cool or dormant periods, keep the plant well ventilated, and wait until the growing medium is dry before watering again.

How to propagate

From seed only. Growth is glacial. Sow fresh seed on the surface of a fine, sterile cactus mix and keep it warm, lightly humid and out of harsh direct sun until germination. Once seedlings are established, increase ventilation gradually and allow longer intervals between watering to reduce the risk of damping off. Young cacti are especially vulnerable to excess moisture. Use a small pot with excellent drainage, provide bright filtered light while roots establish, and move the new plant gradually into the light, temperature and watering conditions preferred by a mature Living Rock.
Cultivation

Quick tips for care & planting

Light
Full sun.
Water
Almost none — a monthly light misting in summer; nothing else.
Soil
Pure mineral: pumice, gravel and limestone chips.
Temperature
-5 to 40°C. Cold-hardy when dry.
Propagation
From seed only. Growth is glacial.