Updated May 2021

Opuntias are the prickly pear cacti. There are over 90 species of Opuntia in the United States. We describe them here.  

Opuntias are unique cacti with unusual shapes and beautiful flowers.  They are part of the opuntiad supergroup of cacti. 

The “big three” states for opuntias are Texas, New Mexico, and Arizona. However, the East has a number of species too. Most states have at least one native prickly pear. The good news is that many western opuntias will grow in a variety of climates. So, you can grow them in your garden. 

Cholla Web is our sister website, and it describes other opuntiads of the USA (chollas and dog chollas).

The Details

Of the many prickly pear cacti in the United States, some have been forgotten by time, and many names have fallen by the wayside. Many species have multiple names because someone named a species in (for instance) New Mexico, whereas someone else named the species in Arizona. Some species look superficially alike, and only close inspection can tell them apart (e.g., O. humifusa and O. mesacantha).

Thus, casual observation might indicate one Opuntia type where there are actually two or more. 

What We Do

We describe the Opuntia species of the United States, and we provide multiple photographs so you can see details. We take photos in habitat so that you can see how the plants look and grow in different seasons. 

We use historical records, herbarium records, and current findings along with our own field studies to identify prickly pears, their differences, and their similarities. 

Our goal is to describe a prickly pear cactus in easy-to-understand terms so that you can find all of them in habitat.

A group of editors verifies all the information on this Website, and we strive for accuracy. But we are always happy to learn new things. Just write to us or leave a comment. If you have an Opuntia, maybe we can help you identify it. 

We generally do not describe Opuntia hybrids though there are many beautiful plants in gardens. Though prickly pear hybrids occur in Nature, they are not the norm. We concentrate on species. 

The Garden

This Website is not about gardening, but we agree that many Opuntia species are excellent garden plants. We like the following plants for gardens.  

What are the best small Opuntias for gardens? 

• O. cymochila
• O. fragilis
• O. humifusa
• O. macrorhiza
• O. phaeacantha
• O. polyacantha
• O. pusilla

These prickly pear cacti are small, easy to grow, mostly cold-hardy, and floriferous: excellent for any garden. They have the added benefit of growing in flower pots, and they are easily obtained too. 

Large, majestic prickly pear cacti are popular in gardens too. Though they require more room, they are worth it because they are amazing statement plants in, or out, of flower. Large plants are found in many southwestern gardens, but you can grow some in the lower Midwest or the Southeast. They are all good bloomers and one produces sweet fruit. 

What are the best large Opuntias for gardens? 

• O. alta
• O. cacanapa ‘Ellisiana’
• O. chlorotica varieties
• O. engelmannii
• O. ficus-indica (sweet fruit)
• O. lindheimeri

Through prickly pears are mostly desert plants, there are prickly pear species that will grow in the Southeast, the Northeast, and the upper Midwest. 

Many opuntias grow naturally in climates without strong freezes, but some come from northern areas or high altitudes that can fly through winters of exceptional cold. We like to grow opuntias, and writing about them helps us and others understand the various species and decide what to grow and photograph.

Conclusion

Opuntia species are part of the supergroup: opuntiads. They are the plants with flat stems also known as paddle cacti.

Their names are confusing and many species are difficult to tell apart. Some species have been forgotten and we try to match up the species we see with the descriptions written 100 (or more) years ago. 

This Website has descriptions of over 90 prickly pear species and over 1500 photographs of them. 

Prickly pear cacti are unique and worth studying because: 

• They are so numerous in the warmer parts of the county.
• They have numerous and incredible adaptations for drought and heat.
• They are important plants for desert wildlife.
• Their ecology is little known. 
• There is much yet to be learned about their basic biology.
• They have a plastic morphology. 
• There are lost or forgotten species to pair with the original descriptions.
• There is controversy about their taxonomy. 
• They have beautiful flowers and edible fruits.