Old man cactus

Old man cactus quick fact sheet

GENUSCephalocereus
FAMILYCactaceae
OTHER NAMESOld man cactus, Bunny cactus, White Persian cat cactus  
SUNLIGHTFull Sun
TEMPERATURE-1F Minimum
CLIMATEShrub-land Arid Tropical Dry
PROPAGATIONSeed propagated
HEIGHT15 meters
WATERStandard succulent watering schedule
OTHERSGrows well in spring/fall Non-toxic Prefers outdoors

What is old man cactus?

The Cephalocereus senilis is a succulent lover’s dream and a fan-favorite among the varied population of succulents.

old man cactus
Cephalocereus senilis @Amazon

Native to the arid regions of Mexico, the old man cactus is a spiky, tall, cylindrical cactus that can reach incredible heights of 10 to 15 meters or more. 

A statement succulent, the Cephalocereus senilis is unmistakable with its shaggy coat of long silver hair, which serves as the source of its nickname – old man cactus. It is reminiscent of an older man’s long unkempt hair.

Apart from giving the old man cactus its unique name and appearance, the long strands of “hair” serve another more critical, less superficial purpose – keeping the plant cool by providing shade from the sweltering sun.

These hairs are not just for decoration. They are a modified form of spines (thorns), and while they may not be sharp enough or hard enough to prick you, they hide a sinister secret.

Concealed below the layer of flowing white hairs are formidable yellow thorns (or spines), and these are sharp enough to draw blood.

Who would have guessed this harmless-looking old man succulent was capable of such trickery and defense?

The bunny cactus is a slow-growing succulent that grows well in pretty hot and arid locations. It is native to Mexico, after all, and last time we checked, Mexico isn’t known for its chilly winters.

Growth

When we say slow-growing, we mean just that. The old man cactus has lovely flowers that will take anywhere between 10 to 20 years to bloom.

However, if you’re patient enough and tend your Cephalocereus senilis for 10+ years, the succulent gods will reward you with beautiful deep red, brilliant white, or sunny yellow flowers that bloom fully at night.

Not many people get to see the Cephalocereus senilis flowers in full bloom, so count yourself blessed should you happen to be part of the lucky few.

Propagation

The old man cactus is a pretty easy succulent to propagate from seeds – a fact that saved it from extinction a few decades back.

Its ease of propagation and increase in cultivation by succulent lovers supplemented the otherwise depleted Cephalocereus senilis that had been growing(dying really) in the wild.

You can gather seeds from its fruit; however, it’s simpler and faster to buy the seeds from your local gardening store or a reputable online vendor due to this succulent’s slow rate of growth.

Soil

Like most succulents, Cephalocereus senilis will do well in a quick-drain soil mix with significant aeration and drainage properties.

Check your local gardening store for pre-mixed cactus or succulent soil; the cactus mix boasts excellent porous and drainage capabilities.

If you’re more of a “hands-on” kind of guy, you can make your soil mix from home, as detailed in this article by Succulent City’s in-house botanical experts:

Learn how to DIY your planting soil at home:

How To Make Your Succulent Soil At Home

Just like any other succulent, the old man cactus isn’t too fond of over-watering. After all, it is endemic to Mexico, and last we checked, Mexico doesn’t make the news for its lush green, rain-soaked plains.

Beginners usually make the mistake of watering their succulents daily. The result is always the same – over-watering leads to the dreaded root-rot, which ends up killing the poor succulent.

Read more about root-rot in this informative article by Succulent City:

What is root-rot? How to fix it.

Just like any other succulent, wait until the soil completely dries out before watering it through and through. When you finally water the old man cactus, soak it through but do not drown the poor guy or leave it sitting in stagnant water.

Succulent cultivation 101: Succulents despise stagnant water.

Learn more about watering your succulents:

Complete Guide to Watering Succulents

Cephalocereus senilis will appreciate growing in a region with full direct sunlight, similar to its native country of Mexico.

The old man cactus is an outdoor growing succulent.

Do not leave the old man cactus outside during winter as this particular cactus does not adapt well to freezing temperatures and tends to go dormant in the winter.

Planting and potting

Most succulent growers plant the old man cactus in a pot (preferably terracotta) and leave it outside during the summer and spring seasons where it can soak up its fill of sun.

When winter rolls back around, they carry the pot indoors and place the succulent under grow lights as a substitute for sunlight.

Sunlight stimulates the growth of Cephalocereus senilis’ long silver hair. The more sun it soaks up, the thicker and longer its silver hair gets.

Pests

The old man cactus is prone to the occasional nasty critter here and there because its long shaggy strands of white hair provide a perfect environment for these pests to hide and nestle in.

Something similar to how lice love to hide in long unkempt hair.

Look out for mealybugs, spider mites, and scale.

Re-potting

Re-potting this particular cactus shouldn’t be a concern, especially when you factor in its slow growth rate – the  Cephalocereus senilis grows even slower when potted indoors compared to out in the wild.

Common practice is to gently loosen the soil around the roots and slowly work the cactus out of the pot.

Inspect the root system – when you notice the roots wrapping themselves around the bottom of the root ball, then it is about time to move this succulent to a new, slightly larger pot.

Where to find Cephalocereus senilis ?

Ask the supervisor down at your local gardening store whether they stock  Cephalocereus senilis seeds.

Home Depot and Lowe’s pack an extensive range of succulents and cacti for sale.

Swap meets and flea markets remain our favorite places to go succulent shopping.

We highly recommend you visit these open-air markets. They are the perfect place to source obscure succulents of all kinds at pocket-friendly prices.

If you’re unable to leave the house for whatever reason (ahem, coronavirus, ahem), then you can opt for online shopping:

  • Buy the Cephalocereus senilis from Etsy for $22.36

or

Check out our Succulent City Facebook page and share pictures of your old man cactus with fellow succulent lovers from across the globe!

Cephalocereus Senilis

Cephalocereus senilis is an endangered cactus from Mexico. It is columnar in size that rarely can branch out, with prolonged growth. The cactus grows only about 4 inches per year. It reaches 3 feet in height raised in the home, and up to 40 feet if wild. They have spines in the form of gray hair that serves to protect them from the cold. Because of their curious appearance, they are called “Old Man’s Head.”. They produce large white flowers. These flowers only bloom at night, in mid-spring or early summer when the cactus is about ten years old. To properly develop their spines in the form of hair, the cactus should be exposed to sunlight. When they are young, Cephalocereus senilis does not withstand temperatures below 50ºF. When they are adults, they can stand even 40ºF.

Cephalocereus Senilis-SC
A picture of Cephalocereus Senilis @floratopia

This species of cactus can live for more than a century. Although this cactus presents its characteristic white hair from the first moment, it is still a prickly cactus. Its spines are yellow and are born just before its coat of fur. It is not recommended to touch them without caution.

Irrigation

The cactus can be grown both, indoors and outdoors. However, it is more common to see it out thanks to its need for abundant sunlight to grow and develop its hair optimally. When produced in a pot, it is advisable to fill it with a light substrate with good drainage; the pumice is an ideal option. But if you are one of those who like to prepare your substrate with a little fine gravel and black peat you can make an excellent substrate for your Cephalocereus senilis. If we want to plant it in our garden, the soil must be equally light. It must not accumulate waterlogging since the Old Man’s Head cactus will not be able to withstand a flood. To take the appropriate precautionary measures, you can dig the hole to plant it and fill it with a little substrate to ensure better soil drainage.

Regardless of the type of crop that we want to give our Cephalocereus senilis, we must consider that water drainage is the most crucial factor. No water must remain. We can use some other materials so that our substrate is safe. And it has adequate drainage which is coarse sand or washed river sand. Which are quite mineral and are not compact since they can rot at the root quickly.

Cephalocereus Senilis-Irrigation-SC
Image: IG@liliacacti_hossein_h

Weather Conditions

The solar explosion is essential for the “Old Man’s Head,” so it should ideally be outside. It would be best if you gave it sunlight, preferably direct sunlight, for long periods. If you are not used to directing exposure, it is best to acclimatize it little by little to avoid damage from burns. The importance of this intense and prolonged exposure is its characteristic hair. These hairs protect our cactus against harmful rays. Besides, the direct Sun helps them grow faster and more robust. The cultivation in totally shaded places can result in partial or even total paralysis in the growth of our Cephalocereus senilis.    

Despite being a cactus and needing direct and prolonged sunlight, the ideal temperature of the “Old Man’s Head” is not very high; it is around 59ºF, being able to withstand interior temperatures of up to 68ºF without significant problem. When the cold and winter seasons arrive, it would be convenient to keep it in a fresh and dry part inside the house. There are adult specimens in the wild capable of facing 32ºF during these freezing times, depending on their age and size. The cactus should not be exposed to such low temperatures or frost, during the first years.

Cephalocereus Senilis-Weather Conditions-SC
Image: IG@cheyennebotanic

Watering

Cephalocereus senilis is a too delicate specimen when it comes to irrigation. Its base is susceptible and prone to rotting if it is watered directly or remains wet for a long time. It does not withstand even high humidity for long periods. Its waterings must be highly moderate and sporadic. It is vital for our cactus that we hope that the earth is parched before thinking about watering it again. The frequency of irrigation will not be the same during the winter, being that in summer we watered little; in winter, it should receive almost no water. This plant should be moistened when the soil is arid, and even then, it is advisable to allow about two days to pass. The curious thing about these cacti is that they are also somewhat susceptible to drought when they are young. If we have them in a pot, we must be cautious in the summertime. To prevent it from dehydrating we must water the soil as soon as it is scorched.

Cephalocereus Senilis-Watering-SC
IG@grancactus

Fertilizing

The spring and early summer seasons are ideal for fertilizing our Cephalocereus senilis. We should provide him with a mineral fertilizer rich in lime or a standard cactus fertilizer to grow his characteristic “white hairs.” Still, it is essential to be careful not to overdose. Flowering occurs in older cacti with more than 15 years of age and usually occurs only outdoors; it is almost impossible to flow in indoor specimens successfully. Its flowers arise from a very hairy body developed on the stem’s sides; they are tubular flowers with red, white, and pinkish pigmentation. These flowers usually fully bloom at night.

Cephalocereus senilis can be easily propagated from seed. It is preferable to do this during spring or summer. We must place these in trays with a cactus substrate. Keep them in a bright area with enough indirect light and water so that the soil remains moist. If everything goes well, we should have germinated seeds between ten and fifteen days after planting them. The “Old Man’s Head” cactus needs to be transplanted every two to three years. During the spring, into a larger container to provide it with a renewed space to grow.

Cephalocereus Senilis-Fertilizing-SC
Image: IG@martynurquijo

Risks

Cephalocereus senilis-Risks-SC
Image: Cephalocereus senilis Risk of Rot

The most significant risks of Cephalocereus senilis are excess water, which can rot the plant efficiently and quickly, and pests of both woolly mealybugs or fungi. Some of these pests are often difficult to detect, thanks to the fact that the “white hairs” cover its stem completely, making it almost impossible to see it with the naked eye; even the thorns are difficult to notice. This feature means we must be vigilant, especially in the summer when these pests usually invade our cactus.

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