(Photograph = Opuntia basilaris x O. santa-rita hybrid, Chris Ginkel)
Introduction
Nature is pretty tough. She is strict. Typically, plants in one species will not breed with plants of a different species, but it does happen. In the hands of humans, in their gardens, the process is sometimes encouraged, and wonderful things can occur.
The Details
Opuntia basilaris is a cactus typically found in the Mojave Desert of California. It is blue-gray or green-gray and is short; it seldom has stems.
O. santa-rita forms a larger plant that often has pads that are tinged with pink or purple. Unlike O. basilaris, O. santa-rita has branches/stems; it grows in the Sonoran Desert.
The range of the two species seldom overlaps and hybrids are rare or nonexistent in Nature. However, two species form hybrids when they are encouraged to do so in gardens. The hybrid plants are created when pollen from one species is placed on the flower of the other species. It doesn’t work 100% of the time, but it works sometimes.
The hybrids are larger than O. basilaris and shorter than O. santa-rita. The color of the pads is spectacular, and the hybrid has other characteristics that are from both parents.
Additional Reading: Patterns of Hybridization in Plants