Old Man Cactus

Have you ever heard of the old man cactus? Consider growing an old man cactus if you want a houseplant with a lot of charm and character! While this fancy plant doesn’t have wrinkles or reside in a retirement home, the body of the cactus is covered in fluffy white hairs. The gentle cushioning of thin, long billowy hair gives it an appearance that is reminiscent of senior citizens.

In the majority of the hardiness zones in the United States, indoor cultivation of this species of cactus is ideal. They thrive as indoor houseplants, even though they usually remain relatively small in pots.

We’ll explain how to grow an old man cactus in this article so you can have this adorable little plant with a fluffy white hairstyle for years to come. But first, let’s break down exactly what this species of cactus is.

What is an Old Man Cactus?

The old man cactus is classified as Cephalocereus senilis. While it can grow to be over 50 feet tall in the wild, when grown inside, one should anticipate relatively modest proportions of three feet tall and six inches wide at most. 

Old man cacti can live for more than a century, which gives their name even more meaning. The majority of the old man cactus’ lower hairy spines disappear with time, while those closer to the developing tip of the column persist.

Growing for its woolly appearance, the old man cactus is one of the most widely used cacti for cultivation as an indoor houseplant. It is occasionally used in arid landscaping.

Anatomy of the Old Man Cactus

The tall, columnar old man cactus has clusters of stems that may reach heights of 16 to 50 feet. Because the individual stems can’t support the weight of side branches, they are often unbranched.

Up the column’s length are shallow ribs. Three to five symmetrically positioned areoles with strong yellow center spines emerge from the ribs. These spines are modified leaves made to withstand the arid climate.

The shaggy covering of long, white hairs on this cactus, which resembles the unruly hair of an elderly man, is its most remarkable characteristic. The hairs, which are really modified spines, give these plants an almost snow-white appearance while protecting them from sunlight and frost. The cactus’ hairs, however, are merely the radial spines. They disguise the imposing, sharp, yellow center spines that contrast with the impression of the hairy covering. 

So, while this cactus looks relatively safe to touch, it can actually be quite painful to get poked by one of its hidden spines.

Old Man Cacti Native Environment

Hidalgo and Veracruz in central Mexico are home to the old man cactus species. While it is endangered in the wild, pressure on wild populations has decreased thanks to its multiplication and popularity in cultivation.

Old Man Cacti Varieties and Subspecies

There are very few known varieties, cultivars, or subspecies of this species of cactus.

Colors of the Old Man Cactus

This species of cactus has a grey-green or deep green color below its furry exterior. While the cactus is young, its coat is a particularly stunning silvery white; as it gets older, the stem starts to shed its covering. It also has center spines that are yellow or cream in hue. This species’ blooms are red, yellow, or white, although they may not bloom for 10 to 20 years after the plant is planted.

What Will Make My Old Man Cactus Bloom?

Like many cacti, getting the old man cactus to bloom can be a bit difficult. It tends to bloom in the spring and usually only blooms at night. Plus, this type of cactus doesn’t usually bloom until it is over 10 years old.

One excellent method to encourage the growth of flowers in this species is to fertilize it with a succulent fertilizer in the early months of spring. If you do this regularly, you can encourage an older cactus to produce flowers.

How to Propagate Old Man Cacti

You can grow your own old man cactus through seed germination or with plant cuttings.

Propagation via Seeds

Cacti cannot be quickly and easily started from seed, unlike many other plants, such as annual flowers or vegetables. It might take two to five years for old man cacti that are produced from seeds to become established. And that’s if you can even locate them to purchase!

Even hydration and strong indirect sunshine are necessary for germination. To create a mini self-watering greenhouse, it is typically advised to cover a seeded potting media with plastic or a humidity dome. Typically, cactus seed germination takes three days to three weeks.

When the seeds have sprouted, it is advised to slightly crack the plastic to let some fresh air in. Remove the plastic completely after three to six months. Once the plants are around a year old, they can be planted in their own pots.

Note the depth of the seedlings in their container before transplanting. For each seedling, use a permeable, well-draining container. It should be one inch bigger than the diameter of the stem of the plant. Cactus and succulent soil should be used to fill up about two-thirds of the pot. Backfill after placing the stem at the same depth as in the initial seed-starting container.

Propagation via Cuttings

You’ll need access to an established plant if you want to start with a stem cutting. Put on some protective gloves and cut through the stem at least four inches down from the tip of the plant during the vigorous growth season in the spring.

Dry the cut area and allow it some time to create a tough callus. Place it on a plate or paper towel out of the way where it may receive strong indirect sunlight for days or even weeks, depending on the size of the stem. When callused, place this cutting in succulent soil just enough to anchor it in place. Be patient, as new roots and growth may not develop for several weeks.

How to Grow an Old Man Cactus

Old man cacti are extremely easy to grow indoors. They make excellent houseplants that can be used as eye-catching living room decor. Potted old man cacti that are kept near windows will undoubtedly capture your attention despite their sluggish growth.

Placing old man cacti close to the brightest windows in your house is the key to keeping them healthy. A window facing south or west is ideal. It ought to be in a space that is at least 65 degrees F, as it is not particularly cold-tolerant.

These plants will develop extremely slowly when grown in pots. You won’t have to worry about these plants outgrowing their containers or taking over the entire space for quite a long time. In general, it’s a great hands-off cactus to grow indoors.

Repotting and Transplanting an Old Man Cactus

You won’t frequently need to repot this plant because of its slow growth rate. To examine if the roots are bound or firmly twisted around the plant with little visible soil, unpot the plant if you notice roots protruding through the drainage hole in the pot.

Water penetration and nutrient absorption are low when the roots are very thick or rootbound. Although cacti love a snug fit, it’s better to step up one pot size and replace the potting soil after the roots start to really fill up the pot. Winter dormancy is the ideal time to repot since there is less stress on the plant than there would be during vigorous development.

Pruning an Old Man Cactus

The good news is that you can choose not to prune your cactus! These plants require incredibly little upkeep. If it becomes too big, you can cut the main bottom branch with clean, sharp shears when it starts to get top-heavy. 

Because the plant is protected by its white “hair”, it can get a bit dusty. Don’t opt to prune these spines off, as they are vital for protecting the plant. Instead, gently wipe your cactus with a damp cloth if you notice it has accumulated a lot of dust. You can also opt to mist it with water to clean it, so you can avoid its sharp spines hidden beneath the fuzz.

Water Needs for Old Man Cacti

Avoid overwatering your old man cactus, as this can cause root rot and other health problems. One thing to keep in mind is to soak them fully until water drains through the drainage holes. Another thing to keep in mind is to wait to give your old man cactus a good watering until the uppermost layer of soil is totally dry. You can arrange a weekly watering for your old man cactus if you wish, but it makes more sense to just let the soil become completely dry before soaking it.

Sunlight Needs for Old Man Cacti

The old man cactus prefer places with full sun, which means they need at least six hours of direct sunshine each day and eight hours of indirect sunlight as well. 

Most cacti grow better when given more light. Consequently, you can tell if your plants are receiving enough sunshine if you notice an abundance of long, thick, hair-like spines. The old man cactus must be placed in a location that receives direct sunshine all day long if it is to flourish indoors. Depending on where you reside, a south-facing sunny window is a fantastic spot.

Grow lights can assist in increasing the amount of light your old man cactus receives if you are worried that it is not receiving enough sunshine. This is a good method for those who don’t have the best natural sunlight in their homes. Avoid using incandescent or mercury vapor-based bulbs because cacti prefer fluorescent tubes or LEDs, according to many horticulturists.

Soil Needs for Old Man Cacti

For growing these cacti indoors, use a cactus mix or a combination of sand, perlite, and potting soil. Use an unglazed container as well to house your old man cactus. This will let any extra moisture in the pot evaporate. The soil should be on the dry side for old man cactus houseplants since too much irrigation might lead to decay and illness.

Fertilizer Needs for Old Man Cacti

An application of fertilizer in the late spring is beneficial to old man cacti. A summertime second dosage is optional, but highly recommended for encouraging flowers to bloom on this species. Use a liquid houseplant fertilizer designed for cacti and succulents that is diluted to half-strength. In terms of the N-P-K ratio, it ought to have more phosphorus than nitrogen.

Temperature and Humidity Needs for Old Man Cacti

The old man cactus can survive outdoors in USDA hardiness zones nine through 10. You can keep your old man cactus in an environment with an ideal temperature range between 71 degrees F and 82 degrees F during the day. There may be a small change in temperature at night.

While it is not cold-resistant, the plant prefers chilly environments down to 59 degrees F. For this reason, it is better to grow old man cacti indoors if the outside temperature is below freezing. Both inside and outside in arid areas, these cacti tend to thrive. The general norm is to keep this elderly little guy warm throughout the winter months when it is dormant.

In general, like most cacti, the old man cactus does not need any additional humidity. When growing this plant indoors, try to keep it in a room with humidity levels under 50%.

Pests and Diseases to Watch Out For

The old man cactus can host a variety of insects, including mealybugs, aphids, and spider mites. Infestations can be easily eliminated by wiping them down with a cotton swap soaked in alcohol. Or, you can use an insecticidal soap that is sold at most garden centers.

Also, because the man cactus likes drier soil, overwatering can cause stem and root rot. Trichocereus fungal disease is another illness that it may get from overwatering. It helps to water your plant from the outside rather than from the top to avoid this from happening.

Another mold infection that results in cactus root rot is Phytophthora cactorum. Brownish staining at the stem base might be the first symptom. The only real effective cure for these ailments is to transplant your cactus into new soil after removing as much of the diseased portions of the plant as you can. Although severe damage may be beyond repair, you might be able to start fresh by taking and rooting a stem cutting.

Is It Hard to Grow an Old Man Cactus?

Not at all. Like many similar cacti species, the old man cactus is easy to grow. The only downside is how much time it will take to reach maturity, When growing from seed, you’ll have to wait quite a while for the old man cactus to reach a hefty size and even longer for it to flower. If you’re a bit too impatient for this, we recommend searching for an established cactus that is at least a few years old.

How cool is the old man cactus? This fluffy little cactus doesn’t take a lot of work to grow, and they can grow in slightly cooler hardiness zones when compared to similar types of cacti. Just make sure it gets the right amount of sunlight, and your old man cactus will definitely live for many years.