While there's a difference between cacti and succulents, they're also closely related. "Cactus" denotes a botanical family. Succulents are a broader group referring to a type of plant included in several botanical families. While all cacti are considered to be succulents, there are succulents that are not cacti.
Cacti and Succulent Popularity
Cacti (the bigger ones, at least) are well known even to those who have little interest in horticulture, likely in part because Hollywood westerns turned cacti into iconic figures. Succulents have also increased in popularity due to their low-maintenance care, making them an ideal choice for first-time plant owners.
Differences Between Cacti and Succulents
Despite their close relationship, there are some important differences between cacti and succulents:
- Cactus plants generally have few or no leaves.
- Cacti are distinguished from the rest of the succulents by the rounded indentations along their stems. These are modified buds called "areoles." From the areoles spring the spines (usually) for which cacti are best known.
- A wide variety of non-cactus succulents are native to different regions across the world. By contrast, almost all kinds of cacti are native only to the New World.
Just as cacti stand out because of their areoles, once you're introduced to the non-cactus succulents, it's usually relatively easy to pick them out from other plants. Because they store water in their foliage and must be tough enough to survive challenging climates, most sport leaves or modified leaves that, while firm to the touch, have a swollen, juicy look (thus the name, "succulent") to them. Succulents range from the tiny "living stone" (Lithops) to the giant saguaro that grows up to 50 feet tall at maturity.
While people do not eat most types of succulents, there are a few varieties that are edible. You can use the tasty, nutritious leaves of purslane (a common lawn weed and succulent) to create salads. Additionally, some people drink the juice from the aloe vera plant.
Succulents that are not cacti include:
- Angelina stonecrop (Sedum rupestre Angelina)
- Autumn Joy stonecrop (Sedum Autumn Joy)
- Chocolate Drop stonecrop (Sedum Chocolate Drop)
- Purple ice plant (Delosperma cooperi)
- Hens and chicks (Sempervivum tectorum)
- Aloe vera (Aloe barbadensis)
- Agave (Agave americana)
- Moss rose (Portulaca grandiflora)
- Flaming Katy (Kalanchoe blossfeldiana)
Examples of Cacti
Cacti and succulents are associated with warm areas such as deserts, but some types are quite cold-hardy. The hens and chicks succulent grows in USDA plant hardiness zones 3 to 11. Among the cacti, 'prickly pear' (Opuntia humifusa) can thrive in a wide variety of climates within zones 4 to 10.
Prickly pear grows in clumps reaching up to 14-inches tall, with a width of almost twice that. As it matures, it becomes more prostrate in its growth habit and bears 3-inch yellow flowers. Depending on where you live, the plant may begin blooming in either summer or late spring. The fruit from which the plant derives its name is called a "tuna."
The flat, bluish-green vegetative parts are referred to as nopalitos or "pads." The pads resemble a bunch of spiny beaver tails stuck together. In fact, the Opuntia basilaris species is actually called the "beavertail cactus."
Other examples of cacti include:
Uses for Cacti and Succulents
These tough, diverse, sometimes beautiful plants might prove useful to you as:
- Xeriscape plants for use in sunny, dry areas
- Plants to grow in between garden stepping stones (in the case of short succulents such as Angelina stonecrop)
- Subjects for your terrarium
- Houseplants that freshen the atmosphere