^{(Photograph = Opuntia spinosibacca, Patrick Denker)}

Introduction

Cliffs and bluffs along rivers can be home to many cacti and succulents. Similarly, rocky soils at the base of the cliffs can make good homes.

The Details

Steep cliffs can be difficult for cacti to colonize, but they can also be safe havens, free from the pressures of browsing deer or cattle. Gentler slopes are easier to colonize.

Unlike popular belief, many cacti don’t prefer pure sand to grow in. They do better in rocky soils where there might be some sand and perhaps small amounts of organic matter; such areas ensure that water doesn’t stay around too long. These conditions abound along western rivers. An occasional flood can even wash cladodes away to colonize new sections areas. Of course seeds wash downstream too.

The West has many rivers with gentle or steep cliffs, many of them good for cactus growth. The Midwest and East support Opuntia species on fast-draining bluffs over rivers. Sometimes O. humifusa grows in the most unlikely rocky conditions above a river, even in New York state.

Steep slopes or their debris can be the home for many succulents around the world, not just the American West.

Additional Reading: Grand Canyon National Park Map