Opuntia and related species (= opuntiads) are unique cacti with unusual shapes and beautiful flowers. Common in parts of the United States and Mexico, they also occur throughout most of the Americas. There are over 90 species of Opuntia in the United States and many more in Mexico and the rest of the Americas. Opuntia Web describes opuntias of the United States. Cholla Web is our sister Website, and it describes other opuntiads of the USA.
Of the many opuntias in the United States, some have been forgotten by time, and other names have fallen by the wayside. Some opuntias look superficially alike and only close inspection can tell them apart. Thus, casual observation might indicate one species where there are actually two. We use historical records along with field studies to identify them, their differences, and their similarities. Moreover, there are still undescribed species, and we will add them to the Website as they are discovered and reported.
What We Do
We describe the various species, and we provide multiple photographs so you can see details. We try to take photos in habitat so that you can see how the plants grow and what they look like in different seasons. The goal is to describe them in easy-to-understand terms. A group of editors verifies all the information in this Website, and we strive to present accurate information. We traveled to many places to photograph Opuntia species, and we visited multiple libraries to find relevant printed information. But we are always happy to learn new things. Maybe you have new information or spotted an error or a typo. If you find an Opuntia, maybe we can help you identify it. Just write to us.
We generally do not described Opuntia hybrids though there are many beautiful plants in gardens. Hybrids are not the norm in Nature and we concentrate on species.
Why We Do It
Opuntias are unique and worth studying. One reason we study them is that they are so numerous in the warmer parts of the county, and three species even grow in Canada. Also, we study them because they are so confusing in the literature and on the Web. It is a fun detective story to find the original publications and match them with the plants. Opuntias make wonderful garden plants if you grow the ones suitable for your climate; they have beautiful late-spring flower displays. Through they are mostly desert species, there are species that will grow in the southeast, the northeast, and the upper Midwest. Many Opuntia species grow in climates without strong freezes, but some come from northern areas or high altitudes and fly through winters of exceptional cold. We like to grow Opuntia, and writing about them helps us and others understand the species and decide what to grow.