Succulents vs. Cacti: What's the Difference?

What's the difference between a cactus and a succulent? Yes, they can look very different, but considering the fact that both flourish in dry climates and neither requires much water to survive, we shouldn't be surprised that they are related. But the two plants have much more in common than their drought tolerance and heat-loving nature.

Is a Cactus a Succulent?

Succulents are not their own distinct family, but can be found in around 60 families of plants. Cacti, in the Cactaceae family, make up one of these families. So all cacti are succulents, but not all succulents are cacti. Cacti are simply a subcategory within a group of plants, which are known collectively as succulents.

All succulents are defined as water-storing plants. The word "succulent" comes from Latin sucus, meaning juice or sap, and the modern word simply means "juicy." These plants can be found in dry, arid climates where rainfall is infrequent, so they rely heavily on dew and mist to survive in between.

The unique shapes and colors that have come to define succulents have made them a popular houseplant in recent years.

Succulent Plant Structure

Succulents feature thick, fleshy leaves that hold water and nutrients during times of drought. Their root structures are typically shallow and close to the surface or the soil to absorb as much moisture as possible. Many types of succulents are equipped with ribs, allowing them to expand in order to hold more water and also get smaller to reduce the surface area exposed to the sun. There are also a number of internal chemical processes that can help the plant retain water.

A defining feature of cacti is yet another way succulents can hold their moisture. A waxy, fuzzy, or spiny outer surface creates a micro-habitat of humidity that reduces air movement around the plant and helps it to stay cool and hydrated. (These spines are also a helpful tool to protect against predators.) The cactus's spines form in clusters on each areole, which is an often dark-colored bump on the surface of the plant. The areoles developed as a kind of branch from the main plant.

Test Garden Tip: It's worth noting that cacti produce spines derived from leaves, while other plants, like roses, produce thorns from their stems.

Some succulents are mistaken for cacti just because they have small thorns or spines. Plants can have these features without being cacti because they do not have areoles.

Cacti evolved 30 to 40 million years ago in the Americas, where today the native plants can be found stretching all the way from Patagonia to parts of western Canada. Succulents, on the other hand, are native to every continent on Earth except for Antarctica. The plants are highly adaptable, and can even be found as epiphytes, growing on other plants without touching the ground.

How to Take Care of Succulents

Succulents (including cacti) make excellent houseplants. When they're potted and cared for correctly (according to their family and variety), they require very little maintenance. In fact, over-watering and infections are the main cause of succulent death. Generally, they just like to be left alone, as long as they have adequate sunlight.

While specific care tips differ according to variety, the biggest rule of thumb when it comes to keeping your succulents alive and happy is to make sure the potting mix is completely dried out before watering. This usually equates to once per week, but that depends on the drainage, humidity, temperature, and sunlight that each plant is getting. If the leaves begin to feel soggy or mushy, your plant is likely being overwatered.

Most succulents and cacti love bright light, but not necessarily direct sunlight. If you are keeping them as indoor plans, be sure to have them near big, bright windows to get as much sunlight as possible. Move them around your home for a few weeks at a time to see how they adapt to different levels of sunlight. You can tell if your plants aren't getting enough sunlight if the leaves start to stretch or the flesh begins to pale.

A well-draining potting mix and container are also essential to the survival of any cactus or succulent. Sand, pumice, perlite, potting soil, or a mix of any of these are common media in which succulents can be planted. Consider filling the bottom of your container with rocks or gravel so water can drain away from the roots and soil.

Propagating Succulents and Cactus

Succulents, like other plants, can multiply via seeds. However, they have had to adapt as wind frequently carries the tiny seeds away from suitable growing areas. Propagation generally refers to a method of multiplying from a piece of the parent plant. There are a few different ways in which succulents can multiply, which can happen naturally or purposefully by a gardener looking to expand their garden's variety.

Vegetative propagation occurs when a stem or offshoot from a parent plant gets replanted and forms its own roots from the cut end after a couple of weeks. This can also happen with individual leaves, which can sprout roots without first being replanted in soil. Both of these methods require a period of healing (or callousing) of a few days in order to seal itself from possible infection from soil and water before the roots can form. Division, on the other hand, is a method of propagation whereby the parent plant produces a pup (also known as a plantlet or chick) near its base. The pup is an independent mini plant, which can be transplanted after two to three weeks of growth near the parent.