Old Man Cactus Care – Growing Cephalocereus Senilis [HOW TO]

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 – planted 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 this interesting tall thin cactus and share growing and care information for it. Read on to learn more.

Old Man Cactus Care Quick Growing Guide:

Uses: Enjoy all year round as a houseplant or outdoors in USDA hardiness zone 11 for xeriscaping.

Lifespan: Up to 200 years in the wild.

Height: Up to 50 feet.

Difficulty: Easy to grow with ample light and heat and tend to neglect watering.

Water: During the growing season, allow the soil to dry thoroughly and then drench the plant and soil. Water very little or not at all during the winter.

Soil: Use very porous, well-draining cactus potting soil rich in nourishment and minerals.

Fertilizer: The potting medium should provide enough nourishment for your hairy cactus. However, you can provide a very weak solution of fertilizer one or two times during the summer months.

Growth Rate: This is a very slow growing fluffy cactus. Kept as a potted plant, it will only put on about half an inch annually. It is unlikely to grow taller than two feet high.

Flowering: Rare, but if it happens it will be early in the spring and at night!

Propagation: Seed planting is preferred. Sow your seeds during the month of May.

Grooming: You don’t need to prune the Old Man, but an occasional shampoo and comb out may be needed. Combing between shampoos is optional.

Why Is Cephalocereus Senilis Called The Old Man Cactus?

Not only does this furry cactus look like an Old Man, 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 fifty feet high.

Cactus experts say the main reason they are able to live so long 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.

You may also hear this cactus referred to by some of its other common names:

  • White Persian Cat Cactus
  • Old Man of Mexico
  • Bunny Cactus

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.

Related Reading: 

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 this 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]

Old Man Cactus Care – Relatively High Maintenance

Unlike many other types of cactus, the Old Man needs a bit of special care. This does not mean the “old man” 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.

These cacti like 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 “Old Man” 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.

Related: 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 fairly 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]