Cephalocereus Senilis (Old Man Cactus) How To Grow and Care 101

Old Man Cacti get their name from the tufts of white hair covering their body, like a grandfather’s head or how wise old men are depicted, with their sparse white beards.

If anything, growing an old man cactus can give an interesting contrast to your green, red, purple, and blue succulents. It certainly has a lot of character.

But how do you take care of an old man cactus? How do you plant it? How much water does it need? Discover everything about this beautiful cactus here.

How to Identify Old Man Cactus

old man cactus

Cephalocereus Senilis, or old man cactus, grows in hot and dry areas. The white hair that covers their bodies protects them from the extreme heat.

These white hairs are the distinguishing characteristic of an old man cactus. It takes a columnar form without any branches because the body simply cannot support the weight of these branches.

The old man cactus can usually grow anywhere from three to 40 feet tall (one to 12 meters). It can also spread as wide as six to 12 inches (15 to 30 centimeters).

When it’s about 10 to 20 years old, it can develop yellow, white, or red flowers. This video will introduce you to the old man cactus and show you how an old man cactus looks like:

Where Does Old Man Cactus Grow

The old man cactus is native to Mexico but can be grown in United States Department of Agriculture zones 9 to 11.

You can grow it indoors, but as potted plants, old man cacti might not grow as tall as when it is planted outside. They can also grow very slowly when kept inside the house.

Uses of Old Man Cactus

You can undoubtedly grow an old man cactus plant indoors. These make lovely houseplants that can serve as attractive decor for your living room. Placed near windows, potted old man cacti are slow to grow, but they can catch your eye.

The secret to healthy old man cacti inside your home is to put them near the brightest windows, preferably one that faces south or west. It should be in a room with temperatures of at least 65 degrees Fahrenheit (18 degrees Celsius).

When grown in containers, these plants will grow very slowly. You won’t have to fret about these plants getting too big for their pots or overtaking the entire room.

Old man cacti also feature in many outdoor gardens. They make towering additions to rock or Mediterranean gardens.

How to Grow Old Man Cactus From Seed

It’s pretty easy to grow an old man cactus to seed. However, you should know that you’d be waiting for a considerable amount of time before you’d see a good-sized old man cactus if you start them from seeds.

Old Man Cactus Growing Conditions

An old man cactus would do well in hot and arid climates. It also requires well-draining soil and hates having its roots wet.

This cactus is relatively easy to grow whether you put it indoors and outdoors. Aside from using the correct soil type and watering it just enough, you only have to fertilize it and keep it safe from insects and pests.

When and How to Plant Old Man Cactus

Sun Gro

Old man cactus can take a long time to germinate. Some sites estimate that these seeds can germinate after three months.

Sow old man cactus seeds in a moist soil mix. Mist it lightly to keep the soil moist but not too wet as you wait for them to germinate. The best time to plant old man cactus seeds is in May, but you can sow them any time from spring to summer.

The soil and the container you use for your old man cactus will help you have an easier time growing it. For the potting soil, it’s best if you buy a cactus mix that you can buy from garden centers or online.

Cactus mix provides your old man cactus with the proper nutrients than regular soil. Further, it will lessen the chance that your old man cactus will be steep in moisture. Regular soil can retain a lot of smoke when you water it.

Some of the best commercial cactus mixes you can buy right now are:

Looking at these cactus mixes, you will notice that they don’t look like regular soil. It’s looser and more porous. If you don’t like buying ready-made cactus mix, you can do it yourself. This video will show you how.

What Container Should You Choose

Now that you have your cactus mix, you will need to choose a pot that will hold it. Most people recommend choosing a container that is a bit larger than your old man cactus.

For instance, if your plant measures three inches (7.62 centimeters) at its widest point, then get something around 3.5 to 4.0 inches, or about 10 percent larger, in diameter.

Further, you should choose a pot that is not glazed. Glazed pots keep the moisture trapped in the soil. Unglazed ceramic or terracotta pots allow the water to evaporate from the sides.

Lastly, when potting any kind of cactus, you should make sure that the container has drainage holes. If your pot doesn’t have one, it can keep the water trapped in the soil, and any excess moisture will not be able to escape.

Old Man Cactus Growing Conditions

To successfully grow an old man cactus outdoors, you will need to make sure that the soil is well-draining. Plant the cactus in an area that gets full sun, and you’d be on your way to enjoying their taller versions.

However, you should remember that old man cactus are not hardy to the cold temperatures of winter. It can die from freezing cold.

That means if you are in an area where temperatures fall below 30 degrees Fahrenheit (-1.1 degrees Celsius), then you should keep it indoors. Or perhaps keep it in a container so that you can quickly transfer it indoors when it starts snowing.

Old Man Cactus Water Requirements

When you’re dealing with an old man cactus, you should avoid overwatering it. Two things to remember is that you should thoroughly soak them until water exits through the drainage holes.

Here’s a video that will show you how to best water your old man cactus and other types of cacti:

Another thing you should remember is to wait until the topmost part of the soil is completely dry before giving your old man cactus a bath.

You can set a schedule to water your old man cactus once a week, but it makes better sense to just allow the soil to dry out entirely before soaking it.

Old Man Cactus Sun Requirements

grow light

Old man cacti want to be in locations where it receives full sun, which means it should be getting at least six to ten hours of sunlight. If you are concerned that your old man cactus is not getting enough sunlight, you can buy grow lights to help augment its exposure to light.

According to this site, cacti prefer fluorescent tubes or LED bulbs, so stay away from incandescent bulbs or those that use mercury vapor. Here are our recommended grow lights:

Best Old Man Cactus Fertilizer

You should only fertilize old man cacti during the summer when they are actively growing. Choose a fertilizer product with low nitrogen levels, but if you have other plants that use balanced fertilizers, you can use that as well.

When it comes to fertilizers, we recommend:

These products will not only help your old man cactus to be healthy, but they will also replenish the nutrients stored in the soil.

Best Old Man Cactus Companion Plantings

cactii in garden

Because of their height and white hairs, old man cacti can give rock gardens and Mediterranean gardens a unique focal point. You can pair the old man cactus with similar plants that thrive under full sun and have low water requirements.

As such, succulents and several types of cacti can be planted alongside the columnar old man cactus. Our recommendations are:

Red Aloe

Red Aloe

Red aloe is ironically an evergreen succulent with rosettes of foliage. Depending on the amount of water and sun they get, the leaves can have various colors, from red to green.

Red aloe grows only up to two feet tall (60 centimeters, but they usually have spikes of red or orange flowers in the late fall or early winter.

Artichoke Agave


Artichoke agave can grow up to two feet (60 centimeters) tall, and it can open up to three feet (90 centimeters) wide. This agave has leaves that are silvery blue.

These beautiful succulents have terminal spikes and flowers only when it is mature. It will only flower once in its entire lifetime.

Bunny Ears


The bunny ears is a perennial cactus that has round or oval pads. These pads are flat, and the whole plant can grow anywhere from three to four feet (90 to 120 centimeters).

As they stay close to the ground, bunny years can provide a good stage for old man cacti. But individually, bunny ears are gorgeous, especially when they have their bowl-shaped flowers in full bloom.

Old Man Cactus Diseases and Common Problems

One of the biggest problems that your old man cactus can have is root rot. The rotting is caused by overwatering or letting the roots stand in too much moisture.

So the best way to avoid root rot is to make sure that you use well-draining soil with your old man cactus, and the pots should be unglazed and have a drainage hole. If you notice signs of root rot, such as discoloration and softening at the base of the plant, immediately take it out of the soil.

Cut all parts that have developed root rot and save the healthy upper half. Keep the healthy part in a dry and cool area and let it callus.

Once it has dried for a few weeks and developed calluses, you can replant it in well-draining soil.


Old man cacti are not that susceptible to many pests and insects. However, it does fall prey to mealybugs that suck the sap out of its body.

Mealybugs are a collection of close to 300 different species of insects. They usually eat new or growing old man cacti. The problem with mealybugs is that they secrete wax that can attract sooty mold fungi.

There are several ways to remove mealybugs from your old man cacti, and you can use different kinds of substances to help deal with these insects.

Spray with Insecticide or Insecticidal Soap

Garden Safe

Mealybugs are insects, so an insecticide will be an excellent way to remove them from your old man cactus. But be sure that they are safe for plants.

We recommend:

Wipe the Mealybugs down with Isopropyl Alcohol

If you don’t have many mealybugs yet, the best way for you to remove them is to soak a cotton ball with isopropyl alcohol. Make sure that what you’re using is less than 70 percent pure, and always test on a tiny area first before treating the whole plant.

The isopropyl alcohol will both kill and remove the mealybugs as well. Other people report that it helps get rid of honeydew.

Wash the Mealybugs off

Another good way to deal with these insects is to take a garden hose and blast mealybugs away with a steady stream of water.

However, you should be careful that the cactus isn’t left in a puddle of water and leave it open to root rot.

Neem Oil

Neem Oil

If you want something more natural and organic, then you should use neem oil. This substance is derived from the neem tree and is a natural insecticide.

Neem oil is also a good miticide, fungicide, and pesticide. As such, you’re not only preventing a mealybug infestation, you’re also getting rid of other scrouges, such as aphids, whiteflies, worms, grasshopper, and spider mites, along with other bugs and pests.

We recommend using the following products:

Just How Do You Get Mealybugs Off an Old Man Cactus

If you think that it’s challenging to remove mealybugs, you’re about to have the challenge of your life if you’re going to have to deal with these insects on an old man cactus.

Because of the spikes and hair, it’s more challenging to get rid of mealybugs. You will need a pipe cleaner or a mascara brush. Check out these products:

You can use any of the substances recommended above, but this video shows you what you can do to remove mealybugs on hairy cacti like the old man cactus.

Spider Mites

Spider mites are small arachnids that are often as tiny as a sugar grain. As such, they might be too small to see with just the naked eye.

They feed off your old man cactus by leeching off the chlorophyll. Getting rid of spider mites, you will be using similar household items to get rid of mealybugs.

But you can add essential oils such as chamomile, spearmint, rosemary, or coriander to that list. According to this study, these essential oils can kill both adult spider mites and their eggs.

Endangered Species

It’s really understandable why so many people would want to add an old man cactus or three to their houseplants collection or perhaps put it in their rock gardens. However, you should know that the International Union for Conservation of Nature has listed this plant on its endangered species list.

This designation means that number of old man cacti in the wild is dangerously low and may become extinct soon. The popularity of this plant fueled the illegal harvesting of mature old man cacti in the wild.

Old Man Cactus Treatments and Maintenance

dr brooners liquid

Old man cacti are very low-maintenance. You don’t have any branches to trim, and you can get away with just leaving it alone as long as the cactus gets full sun and regular watering.

What’s more, it’s deer resistant, so you don’t have to worry about it getting munched on by some doe. Pests and diseases are quickly addressed, as detailed in the above section.

You may need to repot it if it gets bigger and starts to crowd the pot it’s in. You should also clean the hair when it gets dirty. You can do this by mixing water and liquid castile soap, such as Dr. Bronner’s Pure Castile Liquid Soap.

Clean the hairs using this mixture and then wash off the soapy solution. Avoid getting the soap into the soil.

Old Man Cactus Repotting Instructions

When repotting old man cacti, you should use the cactus mix we recommend above. However, if you have regular potting soil lying around, you can use that if you mix it with an equal amount of sand. You can also combine perlite and cactus mix.

When repotting old man cactus, don’t be fooled by its fluffy appearance. It still has spikes that can prick you. Wear a thick pair of protective gloves when you handle any kind of cactus. You can also use a thick folded piece of newspaper to serve as a cushion.

With your gloves, pot, and soil mix, you can now start repotting your old man cactus. This Gay on a Budget video will show you one way to do it:

Where to Buy Old Man Cactus Seeds and Plants Online

If you have the patience to wait to see your old man cactus grow from seeds, you can buy them online from:

However, it might be ideal for those who are impatient to get live plants. Amazon has some sellers of old man cacti, such as:

Planet Desert also sells live old man cacti.

Grow Healthy Old Man Cacti Today

Because of their columnar shape and white hairs, old man cacti can make a fine addition to your indoor plants’ collection, or you can leave it outside and watch it grow tall. All you need are well-draining soil, a bright area where it can receive at least six hours of sunlight, fertilizer, water, and some simple care.

Research Citations

Read more interesting articles here:

Leave a Comment

Your email address will not be published. Required fields are marked *