All cacti are succulents, but not all succulents are cacti. Cactus plants — native to the Americas — store water inside the plant for use later. Both indoor cactus houseplants — such as the Christmas or Easter cactus — and outdoor cactus are hardy plants and relatively simple to care for, and can survive for generations.
Cutting off part of a cactus allows you to not only remove any unsightly growth or diseased portions, but it allows you to alleviate stress from the plant by removing parts of a plant that have grown to large or too quick. You can also keep the legacy of your favorite cactus alive by taking a cutting and giving it to a family member to propagate a new plant.
Use a sterilized sharp knife to cut the cactus stem near the soil line, below the joint. Set the cutting aside for about two weeks to let the fresh cut dry out and form a scab. Replant the cutting by setting it on moist soil and propping it up against the edge of a pot for support. The cutting should begin to produce root and after a few weeks.
Prune your indoor holiday cactus after it blooms to encourage branching out. Since holiday cactus are named for when they bloom, you’ll prune Christmas cactus in the late winter and Easter cactus in the late spring. You don’t have to use a knife to prune the cactus; you can also use your fingers to pinch off the stems.
A plant such as the cow’s horn cactus (Euphorbia grandicornis), looks similar to a cactus, but doesn’t have areoles, and is actually a euphorbia. If you’re unsure if you have a cactus or a euphorbia, make a small cut in an discreet place and inspect the sap; cactus sap is clear and watery, euphorbia sap looks milky white and is sticky.