Old Man cactus has so much character and personality!
Even the botanical name – Cephalocereus senilis – hints at the senility of an Old Man!
The spiky body of this cactus plant is covered with fine white hair which gives the impression of a frail senior citizen – thus the common name.
I first discovered this cactus on a botanical gardens visit to the Sonoran Desert Museum a few years ago. The specimen shown above is likely dozens of years old.
Other common names for cephalocereus senilis are hairy cactus, Old Man of the Andes cactus, hairy old man cactus, Old Man of Mexico, Old man of Peru cactus, and Bearded cactus. Think of an your grandad and his sparse and flowing white hair. Can you see his resemblance to our Bearded cactus?
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Growing old man cactus
Old man of the Andes cactus is native to Mexico and needs a hot and dry climate to prosper. Plant it in the ground for large sized specimens, or use containers for climates that are not as hot.
Learn how to grow this whimsical cactus and you will delight in having this cute little plant with his fuzzy white hairdo living in your home.
Sunlight and soil needs for this cactus
Give cephalocereus senilis well draining soil and lots of bright sunlight.
I treat the cactus as an indoor plant over the winter months and place him on my South-facing deck during the summer and it seems perfect for the plant.
Ideal temperatures are 65° to 90° degrees Fahrenheit in the summer and 50° to 65° degrees Fahrenheit in the winter months, when the plant tends to go dormant.
The plant tolerates lots amount of sunlight and, in this case, more is better. The more sunlight cephalocereus senilis receives, the longer and thicker the hairs that cover the plant will grow.
The best soil for Old Man of Mexico cactus is a pre-made cactus soil or a mixture of sand, perlite and soil that is suited to cacti. I grow my plants in a natural terra cotta pot.
This type of pot allows the water to evaporate out the sides, and this is ideal since cephalocereus senilis likes his soil on the dry side.
One of the most common questions I get about this cactus, is “why is my cactus rotting?” The answer is over-watering.
Be sure to allow the plant to dry out for the top few inches of soil before you water again.
Re-potting old man cactus
This variety of cactus is quite slow growing in a container but can still become pot bound. Every few years, remove the root ball and have a look at it.
When the roots wrap around the bottom of the root ball, it is time to place in a new pot about 1/3 larger.
Add new soil around the root ball to encourage roots to grow.
Pests and diseases
Cephalocereus senilis is slightly prone to attracting pests. This is because insects like to hide in the hair on the outside of the plant.
For this reason, be on the look out for spider mites, mealybugs and scale.
Size of old man cactus
In their native habitat, cephalocereus senilis can grow to 20 feet tall. Fortunately, since most of us grow the plant in a container, the size will be more limited.
Mature specimens grow in clumps and can lose the hair along the bottom edges.
This is even more of a reason for the common name “old man” cactus!
Even though the mature size can be huge, I have had a pair of these cactus plants in a 6 inch terra cotta planter for about 3 years and the height is only about 8 inches tall.
The common name of the cactus does not just refer to the fact that the plant has fine white hair. It is also very long lived. This cactus can live up to 200 years in the wild.
Old man cactus flower
If you have the time to wait (about 7 years) you may be graced with flowers on cephalocereus senilis. This happens all the time on outdoor plants, but plants grown indoors in containers rarely flower.
Flowers are bright pink or red. Fertilizing in spring could give you the reward of flowers if you are lucky.
Pruning old man of Mexico cactus
This plant needs very little extra care. There is no need to prune it, since it grows in one straight line.
The long, soft, white hair protects the plant from both heat and cold and helps them retain moisture, so this results in a generally healthy looking plant.
An occasional spray of water, and combing out of the fine hairs may be needed to clean dust and dirt as well as any insects that it gathers.
Most cactus plants are not hardy in the colder regions of the USA. The reason is not so much the snow as the frost. Cactus plants store water and when that water freezes, the plant will split from the expansion.
For this reason, old man cactus is only cold hardy outdoors in zones 9 and 10.
Propagation of old man cactus
This cactus is easily propagated from seeds. Seeds can be collected from the flowers if you are lucky enough for your plant to have them or you can purchase seeds from a reputable source.
Sow your seeds in soil that drains well. This can be done outdoors in zones 9 and above or indoors under a grow light or on a heated seed mat.
Old man cactus turns into a ghost at Halloween!
When Halloween rolls around, our elderly guy gets a new lease on life. I add wiggle eyes with just a tiny drop of white glue to his fine hairs and he turns into a ghost themed addition to my Halloween decor.
Old Man Cactus is a wonderful addition to any indoor cactus collection.
With the right conditions of a hot, dry and sunny setting, cephalocereus senilis makes a great houseplant as well as a unique conversation piece in any cactus garden.
This fun cactus variety made it onto my list of scary Halloween plants. Check out the others on the list here.
Be sure to also have a look at my post on black plants. They are perfect for Halloween!
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Cephalocereus senilis for sale
I bought my old man cactus from a local garden center. Lowe’s and Home Depot usually also have a good range of cacti and succulents, so have a look there.
My local Farmer’s market is the spot for unusual cacti and they had the plant in stock the last time I checked.
If you can’t find old man cactus locally, there are lots of places that sell it online.
Pin this post for later
Would you like a reminder of this post for old man cactus growing tips? Just pin this image to one of your cactus boards on Pinterest so that you can easily find it later.
You can also watch the video on YouTube.
- I old man cactus plant
- Terra cotta pot
- Cactus soil
- watering can
- Plant your old man cactus in a terra cotta pot. This allows the moisture to evaporate and makes root rot less likely.
- The plant likes a well draining soil. Cactus soil is best.
- Give at least 6 hours of direct sunlight a day. The more light the plant gets, the longer and more the hairs will grow.
- Water well and then allow the top 2 inches to dry out.
- Fertilize once a month with cactus fertilizer in spring and summer.
- Plants in containers are unlikely to flower.
- Cold hardy only in zones 9 and above. Otherwise treat as a house plant if you can give it enough light.
- Inspect for signs of mealy bug and spider mites. The hairs tend to trap them.
- Propagate by seed.
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