Succulents vs Cacti – What is the Difference?
The terms ‘succulent’ and ‘cacti’ are often used interchangeably, but there is a difference between succulents and cacti.
The distinction between succulents and cacti can be easily summed up as follows: “All cacti are succulents, but not all succulents are cacti”.
From this, you may already sense the distinction that must be made between the two — cacti are essentially a succulent subgroup.
In short, cacti are part of the larger group of plants called succulents, which consists of many different plant varieties with the same characteristics related to water storage, photosynthesis and drought-resistance.
If you’re still confused, I’m going to simplify things further down below and help you distinguish cacti from the larger group of succulents and draw up a list of features that will help you understand these concepts even better.
Let’s start with understanding the characteristics of the larger plant group of succulents.
What are Succulents?
Succulents refer to a variety of plants that have the ability to store water in their root system, stems and leaves. This characteristic confers an increased drought-resistance to these plants that are otherwise low maintenance and quite popular in home gardening.
The leaves of succulents are usually thick and, if you were to dissect the leaves, you’d find that they contain a gelatinous substance inside. In fact, the Latin word that the name of succulents originated from — succulentus — means “full of juice”.
This juice is what confers these plants a better resistance to periods without precipitation compared to other houseplants that would easily wither away if you were to miss a watering.
Apart from their water-storing abilities and glutinous mucilage found within the leaves, there are some other characteristics of succulents that defines them:
- Succulents boast a leaf surface texture that has evolved to prevent the plant from losing water too quickly. The texture can range from a shiny waxy surface to hairs and spines.
- Succulents exhibit growth patterns consistent with water preservation — slow and compact growth consistent with energy preservation, spherical or columnar growth with limited surface area to avoid exposure and evaporation.
- Features such as ribs and grooves that allow the plant to shrink during droughts and swell with water when there’s precipitation are also quite representative of succulents.
- CAM (Crassulacean acid metabolism) photosynthesis, which evolved to allow the plant to open its pores only at night when it’s cooler to reduce loss of moisture and take in carbon dioxide needed for the photosynthesis that goes on during the day
- In some succulents, photosynthesis is conducted by their green stems.
- Root system is usually shallow to allow the plant to absorb moisture at the surface of the soil in periods of extreme drought
The agave plant is also among the non-cactus succulents that’s edible and used to make agave syrup and tequila.
Other non-cactus succulents include the moss rose, purple ice plant, Angelina stonecrop, Flaming Katy, and Chocolate Drop stonecrop.
Non-cactus succulents are native to multiple regions of the world, which is another thing that distinguishes them from cacti, which are almost exclusive to the Americas.
Succulents General Keeping Requirements
Succulents enjoy warmth and bright light but should not be blasted with prolonged direct sun exposure or excess warmth. Despite their tolerance to drought, they too can get leaf burn from too much sun exposure.
Pick a commercially available succulent mix soil that’s fast draining and pot your succulent in a terracotta or clay pot. Good drainage and aeration are essential to prevent excess water at the roots of the plant. Clay and terracotta pots will dry faster than plastic, so they’re preferable over plastic pots.
Overwatering is a sure-fire way to see your plant die because of root rot. That said, this doesn’t mean succulents shouldn’t be watered ever.
Many will wrongly believe that just because succulents can store water and have a good resistance to dryness and warmth, they don’t need any watering for extended periods.
Is the soil still moist? Hold off the water and check back in a few days. Is the soil dry? Go ahead and give your succulent a good watering making sure that you empty any excess water that pools in the saucer under the pot.
Keep your succulents away from frost, unless you have a succulent variety that can survive even if kept in more extreme temperatures.
What are Cacti?
So, we’ve established that cacti are succulents too. But what sets them apart from other succulents? Is it the spines or something else entirely?
Generally speaking, when we say cacti, we have a mental image of a plant without leaves or branches and full of spines. And yes, there are many cacti with spines. But there are also cacti without spines.
Turns out that when it comes to cacti, spines by themselves aren’t the most defining characteristic of this plant family. Areoles are.
An areole is a small bump on the surface of a cactus, which can be light or dark colored and serves as the site from which flowers, hair or spines grow out of.
Therefore, with areoles being the most defining feature of a cactus, it follows that a plant that has spines and looks like a cactus, but has no areoles, is not a cactus.
Therefore, if you don’t spot an areole on a plant that looks unmistakably like a cactus, you’re dealing with a non-cactus succulent.
Here are some further characteristics of cacti that helps you better identify them:
- Cacti don’t have leaves or branches, they’re usually a stem succulent that carry out photosynthesis and store water
- Some cacti stems look like pads or flattened segments (they look a lot like beaver tails) of stems such as those featured by prickly pears and Christmas cacti
- The water preservation features mentioned at succulents hold true for cacti too including the shallow root system, the grooved stems, slow growth and column-like or spherical growth
- Flowering and large, colorful flowers that produce fruit
Now that you know to look for areoles in cacti, you’ll be able to quickly tell the difference between a succulent and a cacti, especially that some succulents like those in the Euphorbia genus look a lot like cacti when it comes to their shapes. But without areoles, they remain succulents only.
Even though most cacti are native to arid deserts, there are a few varieties that have a better tolerance to cold such as the prickly pear cactus.
Cacti General Keeping Requirements
Cacti are the ultimate no-fuss plants that are a good match for the occasionally forgetful or the always-on-the-go amongst us.
Once the initial set-up required by cacti is done right, cacti don’t require too much maintenance except for periodical watering and the yearly fertilizing, which isn’t even compulsory.
While succulents should generally be kept away from direct sunlight, cacti will require it for around 4-6 hours per day.
In terms of soil, use a commercially available cacti mix that’s fast-draining and offers good aeration, which is essential to keep cacti healthy and to prevent excess moisture that will rot the root system.
During periods of active growth and blooming, cacti should be thoroughly watered and then allow the soil to dry out before the next watering. In winter, you should hold off the watering.
Keep your cacti in a dry location and warm temperature. Avoid exposing them to cold temperatures outside their tolerated range.
Why Is the Distinction Between Cacti and Succulents Important?
Knowing how to identify a cactus or a succulent will have implications for its keeping requirements even though differences aren’t as stark.
Another reason why it’s good to know what you’re getting is to avoid being tricked into buying something for more than it’s actually worth.
For example, cactus look-alike succulents include those in the Didiereaceae family or the Euphorbia genus, but there are several others that are a striking replica of cactus plants.
Another reason why you must know how to tell a cactus apart from a succulent has to do with blooming. Cacti have lavishly beautiful, large flowers that boast impressive colors. Imagine getting a cactus and hoping it blooms, only to find out it’s a mere succulent that doesn’t bloom at all.
Now that I’ve cleared up the differences and similarities between cacti and succulents, I hope you’re more confident in identifying which is which.
Remember, a succulent that looks a lot like a cactus in all other respects but lacks but its areoles is not a cactus, but merely a succulent that ‘poses’ as a cactus.
The keeping requirements of cacti and succulents are somewhat similar, although there are differences in tolerance of direct sunlight and water requirements.
Whether you have a succulent, a cactus, or both, make sure to familiarize yourself with the requirements specific to your variety to make sure you meet all their requirements.