The Cactus

Cacti are among the most amazing and durable plants in the world with an ability to store enough water to live for up to two years and live longer than most other plants on the planet… up to 200 years! Pictured are the iconic Saguaro Cacti surrounded by Teddy Bear Cholla Cacti at the Desert Botanical Garden in the northern fringe of Phoenix, Arizona, USA, in the Sonoran Desert. (Ecology Prime™ photo by Eric McLamb)


plural – Cacti or Cactuses, also Cactus.

Status: Endangered to Critically Endangered.

The Cactus plant is one of the most fascinating, heartiest and longest-living plants in the natural world.  There are over 1,800 different known species of cacti (exact numbers vary among botanists) which occur in wide-ranging shapes and sizes.  They are almost entirely indigenous to the desert regions of North and South America with a notable exception, the mistletoe cactus, which is native to eastern Africa and Sri Lanka in south Asia.

The Mistletoe Cactus, found in eastern Africa and south Asia. (Wikimedia Commons 3.0 photo by Frank Vincentz)

These flower producing plants survive some of the most extreme desert and arid climate environments due to their complex structure.  Despite extraordinarily harsh conditions, they can live as long as 200 years… longer than most other plants.  Perhaps the most unique survival feature of the cactus is its ability to collect, store and retain water for long periods of time… some up to two years!

Amazing Water Storage System

Cacti have shallow root systems that enable them to absorb as much water as possible, up to 200 gallons as is the case with the iconic Saguaro cactus.  Their roots are very shallow, only about a half-inch (1.3 cm) deep, which allows them to absorb any rainwater as soon as it hits the ground and before the rain can evaporate in the extremely dry conditions.  In fact, you can tell if it has rained recently in the desert by seeing how swollen the cacti appear.

But be cautioned… despite scenes from film and television showing people drinking the water stored by a cactus, it is not considered safe to consume.  Not only is cactus water thick and gooey, it is extremely acidic and can cause serious illness and vomiting.

Fishhook Barrel Cactus, Saguaro National Park, Arizona, USA (Sonoran Desert National Park Service)

Botanists have reported that there is one cactus you can drink water from, but it should only be consumed in very small amounts and only in extreme emergency or dire need.  It is the Fishhook Barrel Cactus which is scattered throughout the Sonoran Desert from northern Mexico to central Arizona in the United States.

Survival and Those Prickly Spines!

The most distinctive feature of the cactus is also essential to its survival… those prickly spines!   Amazingly, those wicked spines are actually highly adapted leaves that grow from extremely reduced branches called areoles.  It is from the areoles that flowers, more branches and leaves also will grow.

At first glance, the spines of a cactus protect it from predators that have the misfortune of coming into contact with them, from rodents, birds and insects to humans.  But their deeper functions are to provide shade to slow evaporation and by absorbing the slightest traces of water from the desert wind.

Beyond the rugged beauty of its spines is the cactus’ distinctive, discernable beauty presented through its flowers.  Every cactus produces flowers, and their blooms are among the most brilliant and fragrant of the flower-bearing plants.  They are produced by the cactus’ areoles, and it is only for a short period of time.  They will only blossom if enough water and nutrients are available, and only one flower will sprout from each areole during the lifetime of the cactus.  Only very few cactus species can produce multiple flowers from one areole.

Prickly Pear Cacti in the Swiss Alps (Twitter | Romain Boisset)

While the desert climate is where cacti flourish, they can also prosper in other climates from the lush tropics to snowy mountainsides.  The Prickly Pear Cactus, which is commonly found in the Grand Canyon in Arizona, USA, is also thriving in the Swiss Alps!  Made possible in large part due to the warming effects of climate change, Prickly Pear Cacti can survive temperatures as low as -15°C (5°F).  The Prickly Pear Cactus is not indigenous to the Alps, however, having been introduced to the Alpine ecology some 200 years ago by travelers from the Americas.  They are an invasive species to the Alps which are threatening many of the region’s native plants.


Given its complex and robust capability to survive and even thrive in the harshest of environments, it is no wonder that many cactus species can live up to 200 years.  And they have also been around for several millennia according to the archeological record. The cactus dates back to as long as 12,000 years ago when hunters and gatherers would collect wild cactus fruits as a source of food.

Endangered Status

Despite their extreme capabilities to adapt and survive, many cactus species are seriously endangered.  According to the International Union for Conservation of Nature’s Red List of Threatened Species (IUCN Red List) – which lists 1,502 species of cactus, 31% of all cacti are close to extinction, primarily caused by human activity from converting its habitat for farming and urban development to harvesting them for private use. 

Whether in the wild or cultivated for private use in home settings, the cactus plant amazes as much as it stuns with its distinctive beauty and remarkable, natural built-in adaptation and survival system.  But respect its prickly spines…. they are as rugged as their reputation! — Ecology Prime™

Cactus Fast Facts!

The blooms of Echinopsis Tubiflora – also called Hedgehog Cactus. It is native to Argentina, Southern Brazil and Mexico. (Pexels photo by Dillon Pena)
  • Also Known as:  New World Plant, Prickly Plant
  • Family: Cactaceae (Cactus)
  • Number of Species: 1,866 (numbers vary among botanists)
  • Type: Succulent perennial plants; angiosperms (flowering plants).
  • Colors: Green, Red, Yellow, White, Purple, Orange.
  • Size (fully grown): From less than one inch (2.5 cm) to over 60 feet (18.3 meters). Varies per species.
    The tallest cactus ever measured was an armless Saguaro cactus in Cave Creek, Arizona, USA, which perished in a windstorm in 1986. Located in the Sonoran Desert, it was 78 feet (23.8 meters) tall and estimated to be 150 years old. Standing 63.0 feet (19.2 meters) tall, the tallest reported living wild cactus is a specimen of the Mexican Giant Cardon in northwestern Mexico.
  • Range (native species): Primarily western North America from the Alberta and British Columbia provinces to the southern Patagonia desert region of Chile and Argentina in South America. One known indigenous species is native to eastern Africa and southern Asia. Mexico has the greatest concentration and variety of native cacti.
  • Life Span: From 10 to 200 years, depending on the species.
  • Predators: Rodents, birds, insects, other plants, humans.
  • Threat Status: Over 31% of cactus species are listed as Endangered to Critically Endangered, according to IUCN. Reasons are primarily attributed to human activity including farming, ranching and collection for private use.

Additional Readings about Cactuses

The Saguaro Cactus, Sonoran Desert outside Phoenix, Arizona, USA. (EP Photo by Eric McLamb)