Old Man Cactus: How To Grow and Care For Cephalocereus Senilis

The cactus Cephalocereus senilis (old man cactus) is an odd-looking plant that needs a place in every indoor cactus collection or in an outdoor cactus garden given the right climate.

Their unkempt cactus with white hair makes them a real standout in any setting. These interesting Mexican natives are fairly hardy and easy to grow, and it is endangered in its native habitat in eastern Mexico. [source]

Old Man Cactus - Botanicactus - Mallorca, Spain
Hairy Old Man Cactus Cephalocereus senilis – growing in full sun at Botanicactus – Mallorca, Spain
Image via Frank Vincentz from Wikimedia  CC 3.0

Cultivating them is a good way to preserve them.

In this article, we discuss the interesting tall thin old man cactus and share growing and care information for it. Read on to learn more.

Quick Old Man Cactus Care Growing Guide

  • Botanical Name: Cephalocereus senilis – (yoo-FOR-bee-uh) (try-GOH-nuh) {set-al-oh-SEER-ee-us) (se-NIL-us)
  • Common Name(s): Old Man cactus, hairy cactus, Old Man of the Andes cactus, hairy old man cactus, Old Man of Mexico, Bearded cactus
  • Family & Origin: Cactaceae – Mexico
  • Growability: Very easy to grow, slow growth rate
  • Grow Zone: USDA hardiness zone 11
  • Lifespan: Up to 200 years in the wild.
  • Size: Outdoors 20′ feet tall | Indoors 24″ inches tall
  • Flowering: Rarely, delightfully fragrant pink flowers opening at night, seldom flowers indoors
  • Light: Prefers bright light even full sun.
  • Temperature: Summer 65° to 90° degrees Fahrenheit | Winter maintain 50° to 65° degrees Fahrenheit
  • Water: Water only when the soil is thoroughly dry in summer. Water little or not at all during the winter. Do not overwater.
  • Fertilizer: Add a weak liquid cactus food to the water once or twice in the summer.
  • Soil:  Use very porous, well-draining cactus potting soil 
  • Pests & Diseases: Mealybug, Red Spider, root rot
  • Propagation: From seed planted in May
  • Grooming: No need to prune, but an occasional shampoo and comb out may be needed to clean dust and dirt.
  • Uses: Enjoy all year round as a houseplant

Why Is Cephalocereus Senilis Called The Old Man Cactus?

Not only does this furry cactus with white hairs look like an Old Man, but it is also incredibly long-lived.

When grown in the wild in their homeland, some of these cacti have been known to live as long as two-hundred years and grow to be 20′ feet tall.

Cactus experts say the main reason they are able to live for so many years is that their long, soft, white hair protects them from both heat and cold and helps them retain moisture.

Although the long white hairs on the top are soft, this cactus must still be handled with care. The shaggy hair covers very sharp yellow spines.

The scientific name of Old Man cactus is derived from both Greek and Latin. Cephalocereus comes from the Greek word, kephale, which means “head”, combined with the Latin word, cereus, which means “candle” or “wax taper”.

The name of the species is the Latin word, senilis, which means “Old Man”. Loosely translated, this cactus is a tall, thin Old Man with a head.

Does The Old Man Cactus Grow Better Indoors or Outdoors?

Old Man Cactus is a good looking addition to any indoor plant collection. With the right hot, dry sunny setting the “old man” makes for a stunning conversation piece in your outdoor cactus garden.

The Old Man of Mexico is a bit picky and has very specific requirements to survive and thrive.

If you can provide the right outdoor conditions, your plant will grow impressively large and will be more likely to flower. If not, keep it indoors where you can control its environment.

What Do The Cephalocereus Senilis Flowers Look Like?

In the wild, Old Man Cactus produces pretty pink, fragrant, night-blooming flowers early in the spring from the head of the plant.

When kept in an indoor setting, these cacti very rarely produce flowers.

Can You Grow Old Man Cactus From Seed?

It is actually best to grow this cactus from seed. Some experts say is the only way to grow them.

Trying to grow from cuttings or grafts can be a very tricky, and it’s easy to order seed online or purchase it from a cactus specialty nursery.

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Like succulents, to plant it, prepare a shallow tray or pot of good potting soil. Spread the seeds evenly over the surface of the soil and mist with a spray bottle.

Cover the soil lightly with plastic wrap to hold in moisture and place the tray in a warm place with plenty of bright, indirect light.

Mist as needed to keep the soil very slightly moist. It may take three months for your seeds to sprout.

Here is an alternate method for starting cactus seed in vermiculite and then transplanting the seedlings to a 50/50 sand and potting soil mixture.

Although growing the Old Man cactus from seed can be fun, it does take a very long time.

In addition to the three-month germination period, these are very slow growing cactus. It will be quite a while before you have a nice specimen to add to your collection.

For these reasons, you may decide that purchasing one is the best idea.

As with all cactus, when buying check the base of the plant carefully to be sure you are not getting a cactus with root rot.

Additionally, because Cephalocereus senilis is endangered in its natural environment, only purchase nursery-grown plants and not those “poached” in the wild. [source]

Hairy Cactus Care – Needs Some Extra TLC

Unlike many other types of cactus, the Old Man of the Andes needs a bit of special care. This does not mean the Cephalocereus senilis is hard to grow, just needs special attention.

It just requires It likes very specific soil and environmental conditions.

This, along with “cactus poaching” may explain why it is endangered in what has been its natural habitat.

The Cephalocereus senilis likes lots of bright light and heat. During the summertime, they should be kept in full sun in a window or setting with southern or western exposure.

It is important to allow the soil to dry completely and then drench the plant thoroughly. Light, frequent watering can cause rot.

Related: Growing The Prickly Pear Cactus

In the wintertime, keep your Old Man Cactus in a very bright, cool, dry setting. It prefers temperatures ranging from 50° to 60° degrees Fahrenheit and very little watering.

It is also very important to get the soil just right. A good quality cactus mix is fine, or you can make a cactus mix using regular potting mix and sand – 50/50.

The potting soil you use should have a high mineral content and provide plenty of nourishment.

Grower Tip: Plant your Cephalocereus senilis in an unglazed or terracotta pots to absorb excess moisture and keep the soil medium on the dry side.

Once potted, these cacti do not like to be disturbed. Only repot once every three-to-five years.

In addition to needing extra care in terms of temperature, sun exposure, and watering, Old Man Cactus may also need an occasional shampoo.

If the hair becomes dirty or discolored, you can wash it with a mild mixture of water and organic soap, such as a liquid castile soap.

Rinse the plant under the tap with clear water to remove all traces of soap, and comb the hair in an upward direction to dry.

Place the plant in a warm area with good air circulation to facilitate quick and thorough drying.

Does Old Man Cactus Have Pest And Disease Problems?

Overwatering is the main cause of problems for this cactus. Wet roots cause rot, and rot attracts pests.

Mildew can be a big problem because of the long, soft hair.

That’s why it is so important to water correctly and to make sure your Old Man dries out properly after a shampoo. If mildew sets in, it will spread very quickly and kill your plant.

A spider mite infestation or an outbreak of mealybugs (that white fuzz on the cactus) may hide in the cactus’ long hair. Check for them occasionally throughout the year and when you repot the plant.

If you see any of these pests, treat with a mild insecticide or insecticidal soap.

Check out this Recipe For Homemade Insecticidal Soap

Alternately, just give your plant a shampoo as described above with a insecticidal soap. Keep a sharp eye out for re-infestation.

Old Man Is A Personable Cactus!

This cactus is popular because of its interesting, long, silver hair that makes it look like a fairy tale troll or an Old Man.

These days, quite a few people have taken to calling it “The Bernie Sanders Cactus”! Curators at Liberty Hyde Bailey Conservatory at Cornell University recount hearing a visiting preschooler calling it just that. [source]

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