The Old Man Cactus, botanical name Cephalocereus senilis, is a columnar cactus that can grow to be up to 50 feet tall. It is native to the Hidalgo region of Mexico, usually on mountainous landscapes.
These tall cacti take over 15 years to reach maturity, but they are being aggressively harvested from their natural habitat. So much so that wild specimens don’t have a chance to reach maturity more often than not. It is an endangered species due to overcollection for the horticultural trade.
Old Man Cactus is a popular garden cactus and can be found in many homes and gardens.
It has a thick, solitary, sometimes branched trunk covered in soft, hair-like, white spines. These spines give the cactus the appearance of a wizened old man, hence the name. Interestingly enough, these are not the only spines on this cactus. A spikier and much more prickly variety of spines are also present; it’s just that the long and soft spines cover them, so they’re not visible from afar. Don’t go touching the column without protection; you’re likely to injure yourself.
The trunk greys with age and experiences drastic changes in its upper portion; the wooly, white hair becomes much denser around this area, they lose chlorophyll, and the areolas come closer together. This is all in preparation for the main event: the flowering. Take note that this only occurs in mature plants, and even then, it takes some time for the cactus to settle into its maturity. Flowers are nocturnal and appear one after another, not all at the same time. Fruits appear after a month of flowering.
- Old Man Cactus Main Characteristics
- Old Man Cactus Care
- Propagating Cephalocereus Senilis
- Potting and Repotting Old Man Cactus
- Common Pests and Diseases
- Care tips for the Old Man Cactus (Cephalocereus Senilis) – How to keep your cactus healthy! (Video)
Old Man Cactus Main Characteristics
|Common Name||Old Man Cactus|
|Botanical Name||Cephalocereus senilis|
|Synonyms||Cactus bradypus, Cactus senilis, Cephalophorus senilis, Cereus senilis, Echinocactus senilis, Echinocactus staplesiae, Pilocereus senilis|
|Native Range||Eastern Mexico (Hidalgo and Veracruz)|
|USDA Hardiness Zones||9 to 11|
|Mature Size||Height: 10 to 50 feet; Spread: 6 to 12 inches|
|Propagation methods||by seeds, by cuttings|
|Sun||Full sun, Bright shade|
Old Man Cactus Care
Growing an Old Man Cactus is not difficult, but it does require some specific conditions. It’s also important to note that this cactus is cold hardy down to USDA Zone 9, so gardeners in colder climates will need to provide a sheltered spot for their plants. Nonetheless, if you’re looking for a unique plant that is easy to care for, the old man cactus may be the perfect choice for you!
Light and Location
Although it grows in direct sunlight in its native habitat, indoor cultivation is slightly different. It still needs plenty of light to grow well, but some shade wouldn’t go amiss either. It can handle full sun in colder climates but will need some shade in hotter climates.
Old Man Cacti appreciate a good watering during the growing season, more so than some of their cousins in the cactus family. Water when the soil is dry to the touch, and make sure that the pot has drainage holes to avoid waterlogging. Water the plant only to keep the soil from completely drying out during the winter months.
Old Man Cactus can tolerate a wide range of temperatures but prefers intermediate to warm climates. It can handle temperatures down to USDA Zone 9 but won’t do well in moisture. Optimal temperatures range from 60-80 degrees Fahrenheit.
Old Man Cactus does best in a low humidity environment. Less moisture means a higher chance of the plant surviving extreme colds. Be particularly mindful if your area regularly experiences cold drafts.
Cephalocereus senilis’ characteristic slow growth won’t speed up by any fertilizer. But if you’ve been keeping your cactus outdoors, there is a slight chance that a small dose of feed in early spring might yield flowers. Remember, this is only an option for mature specimens.
Propagating Cephalocereus Senilis
Old Man Cactus can be propagated by both seeds and cuttings.
If you’re using cuttings, only cut from a branching stem. If you cut the main trunk, you’ll stunt the cactus’ growth for months to come. Then, give the cut end a few weeks to harden and callus over. Once the wound is good and healed, plant the cutting into fresh soil with the cut end buried in the potting medium. Cuttings take root easily.
Seeds are also an option and quite a viable one. They will germinate in 2-3 weeks and can be direct sown into the soil. Cover the seeds lightly with soil and water well. Unlike their fully grown counterparts, seeds want high humidity in order to germinate; wrap a plastic wrap around the pot to trap the moisture in.
Potting and Repotting Old Man Cactus
Cephalocereus senilis can get quite large, so it’s best to plant it in a too big pot rather than too small. Choose a well-draining potting medium; a cactus mix is a safe choice, and it’s available everywhere. Mineral-rich soils are a must if you’re hoping for consistent growth; these plants thrive in them.
Old Man Cactus can and will outgrow its pot. But because of their slow growth, they won’t need frequent repotting like other plants might. Once every 3 to 4 years should be sufficient. If you live in an area with a shorter growing season, you can wait even longer between repottings. When the time comes, carefully remove the cactus from its pot and check the roots. If they’re tightly bound, then gently loosen them before repotting. Be patient and avoid damaging any roots in the process. Choose a pot that’s only slightly larger than the root ball and has drainage holes.
Cephalocereus senilis is non-toxic to both people and pets.
Common Pests and Diseases
Old Man Cactus is quite hardy and doesn’t suffer from many pests or diseases. If you find any, it’s most likely because of an inadequate watering or fertilizing routine. Root rot can sometimes occur, but you can easily avoid it by keeping the plant dry.