Cactus closeup with water

When cared for properly, cacti can last decades. And the good news is, taking care of them doesn't require too much work and attention.

Cacti come in a wide range of shapes and sizes. These unusual plants can survive in harsh, arid environments like the Atacama Desert in Chile, one of the driest places on earth.


San Pedro de Atacama, Antofagasta, Chile shot by Thulio Philipe via Unsplash
The Atcama Desert shot by Thulio Philipe on Unsplash


Cacti make great houseplants in Canada because they can go long periods of time without water in the winter. Since they're used to living in areas subject to drought, you won't have to worry about watering them if you go away for a month or two. Just be sure to put them in the brightest room in your house. 

Most cacti are native to the Americas and can be found from Patagonia to Canada. Today, cacti are found worldwide as a popular component of modern landscape architecture and interior design.

Some cacti are resilient enough to live outside in Canada during the winter. Opuntia fragilis, The Prickly Pear Cactus, has adapted to live outside in Canada in sub-zero temperatures.

A close relative to the succulent family, Euphorbias, commonly referred to as cacti, are native to the Middle East and Africa. These plants share many similarities in terms of hardiness and drought tolerance, but technically they fall into a different scientific category.


The Desert Candle Cactus is a Euphorbia This Peruvian Cactus is a true cactus

Ways Cacti Make Your Environment Healthier

  1. Air Purifying: Like many plants, cacti absorbs carbon dioxide at night to release oxygen. Putting cacti in the room helps sleep and supplement oxygen.

  2. Absorbing Radiation: Cacti can absorb radioactive waves (according to NASA). From cell phone towers to your phone, it's interesting to think of these living and breathing organisms with the power to protect you against radioactive waves.


How to keep your cactus alive in Canada

A lot can be learned about caring for plants by studying their natural environment. Cacti are native to the desert, where rain is minimal, and the sun is plentiful. They like it hot, dry and store a tonne of water naturally, so make sure to treat them the way nature treats them.

  1. Give your cactus lots of sunshine
  2. Keep your cactus in a warm dry place
  3. Water a cactus rarely in the winter and sparingly in the summer


The four types and varieties of cacti

Cacti are grouped into four major categories based on how they grow. There are three common types; Arborescent cacti, Columnar cacti, and Globular cacti. The fourth category is a catchall of “Other Forms.”

the four different types of cacity - promise supply

1. Arborescent cacti are tree-like cacti. Some of these may not be recognizable cacti. The Prickly Pear cactus that can survive a winter would be a member of this family as well as one of our personal favourites, The Peruvian Cactus (Cerus repandus).

2. Columnar cacti may or may not branch; they tend to grow into a form that is similar to shrubs rather than trees. Some can get quite tall when older, but in general, they tend to grow wider. Some will even grow horizontally. If you’re looking to get a small cactus, Columnar cacti are commonly available anywhere from here at Promise Supply to your grocery store plant section.

3. Globular Cacti are the shortest of the bunch. They grow both horizontally and vertically and often resemble a prickly ball. Mother-in-laws seat, Echinocactus grusonii, is a Mexican native that grows in this pattern.

4. Other Forms of Cacti include some of the strange varieties that round out the family. Many of these will grow on top of other plants and are known as Ephythetic plants. Some of these can include popular forms of cacti such as Schlumbergera, The Christmas Cactus and Rhipsalis, The Mistletoe Cactus.


What makes a cactus prickly

Most species don’t have leaves and only grow spines. Spines evolved from leaves over time. These spines protect against animals who might eat these plants. Spines, like almost every other adaption, are also related to water conservation. They help prevent water loss by reducing airflow close to the cactus and providing some shade.

Why Cacti Don’t Have Leaves

Most Cacti don't have leaves. In some edge cases, they might, but Cacti do not have any thin leaves for the most part. Like most things, this has a lot to do with conserving enough water to last months without rainfall.

Cacti have Areoles instead of Leaves

Cut Cerus, Areola example

Cacti contain a structure called an areole. Areoles set cacti apart from all other plants. The areoles bloom flowers, new branches, and all different kinds of spines. They typically appear as woolly or hairy areas on the stems where the spines emerge. Cephalocereus senilis: The "Old Man" cactus shows off this idea of woolly areoles more than any other cactus we carry at Promise Supply.  (Shop Here)

Cacti Can Perform Photosynthesis in the Stem instead of Leaves

Photosynthesis takes place in the stem. If trees did this, it would be the trunk taking in light, carbon dioxide and sucking up water to create energy. The stem of a Cactus is green, unlike trees, because it has chlorophyll, just like leaves. These green stems mean that the entire organism can perform photosynthesis instead of just having leaves create energy.How Cacti Develop Their Flowers

All cacti flower these flowers allow them to create seeds and reproduce. The type of flowers ranges greatly. Some, such as the Dragon Fruit Cactus and Peruvian Cactus, produce edible fruit. Cacti flowers can add colour to your home in ways that other hardy tropical plants rarely would.
Mammillaria: Globe Cactus (Shop Now)

How Cacti store water to survive in the desert

Cacti roots allow them to take in a lot of water really quickly

Cacti have adapted to take advantage of even the lightest of rainfall by having roots close to the surface, they can often expand outward instead of downward in order to pull in as much water from their surrounding area as possible.

A fully grown saguaro, Carnegiea gigantea, is able to absorb as much as 760 litres of water during a rainstorm. Their ability to absorb water quickly through their stem and hold it in their stem is one of the reasons why most people kill their cacti from overwatering it.

Water is quickly collected by the Cacti roots and stored in thick, expandable stems for the long summer drought. 

The Shape and Structure of a Cactus Helps collect and retain more water

A cactus with water on it

Many smaller cacti have globe-shaped stems, combining the highest possible volume for water storage, with the lowest possible surface area for water loss when they are taking in carbon dioxide and releasing eater and oxygen for transpiration.

When water is no longer available in the summer, many desert shrubs drop their leaves and become dormant. Cactus continue to photosynthesize because they have fixed spines instead of leaves. The green stems produce the plant's energy but lose less water than leaves because of their sunken pores and a waxy coating on the surface of the stem. The pores close during the heat of the day and open at night to release a small amount of moisture.

Many cacti have ridges and other unique shapes that allow them to direct more water towards their root system. For example, the barrel cactus's fleshy stems are pleated like an accordion and shrink as moisture is used up. These pleats also channel water to the base of the plant during rain showers.

The dense network of spines shades the stems, keeping them cooler than the surrounding air. Many barrel cactus lean to the south so that a minimum of body surface is exposed to the drying effect of the midday sun.

Releasing Oxygen at Night Helps a Cactus Save Water

Most succulent plants employ a special mechanism called "crassulacean acid metabolism" (CAM) as part of photosynthesis. They take in carbon dioxide and release oxygen at night, this process is called transpiration, and most plants do this during the day while they are using sunlight to create energy through photosynthesis. When plants transpire, it takes in carbon dioxide and releases water and oxygen. Cacti can conserve more water than other plants by doing this at night when it is colder.

Transpiration, during which carbon dioxide enters the plant and water escapes, does not take place during the day at the same time as photosynthesis but instead occurs at night.

Why Cacti Grow Slowly

A Cactus pays the price for its water-saving adaptations -- slow growth. Growth may be as little as 1/4 inch per year in the barrel cactus, and most young sprouts never reach maturity.

Their ability to stay alive through harsh times directly correlates to their inclination to take growth slowly. Combine that with dormancy during the winter, and you have a tiny window for growth. A 6-foot tall Peruvian cactus is the result of 3 to 4 years of growth under ideal conditions. This is one reason why we get so excited when we see extra-large cacti like the ones we found PS0001: The Desert Collection.

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