What is Opuntia nicholii?
Opuntia nicholii is an uncommonly encountered prickly pear cactus occurring in isolated locations in far-north, central Arizona and adjacent southern Utah.
O. nicholii can be large and sprawling, stretching up to 2 m or more across but less than 30 cm high. Cladodes are obovate to narrowly obovate and 10-20 cm long. Major spines are 4-12 cm long and stout and generally occur in every areole. Spines (1-5 per areole) are down curved, ascending, and pink-gray or the lower portion gray to black.
Flowers are typically pink or magenta, 5-8 cm across, and showy. Fruits are 2-5 cm long, spiny, and dry at maturity. Like O. polyacantha, the fruits of O. nicholii are dry at maturity and the seeds are large.
O. nicholii is hexaploid.
The Flora of North America reports that O. nicholii grows in “barren areas with saltbush and ephedra, limestone or red, sandy soils,” around 4000 ft. Some plants of O. nicholii vary from typical spination, perhaps through introgression with other species.
Even though the plants are large, it was once proposed that O. nicholii was a variety of the smaller O. polyacantha rather than a distinct species. However, unlike the hexaploid O. nicholii, O. polyacantha is tetraploid.
Due to is spiny nature, magenta flowers, and large sprawling branches, this O. nicholii makes a great plant for large gardens.