Mammillaria senilis

Mammillaria senilis after it came in the mail at 1″ tall x 1 1/2″ wide on 11-30-20, #766-2.

Mammillaria senilis

mam-mil-AR-ee-uh  SEE-nil-is

Synonyms of Mammillaria senilis (9)(Updated 12-24-20): Cactus senilis (Lodd. ex Salm-Dyck) Kuntze, Cochemiea senilis (Lodd. ex Salm-Dyck) Orcutt, Mamillopsis diguetii (F.A.C.Weber) Britton & Rose, Mamillopsis senilis (Lodd. ex Salm-Dyck) F.A.C.Weber ex Britton & Rose, Mammillaria diguetii (F.A.C.Weber) D.R.Hunt, Mammillaria haseloffii C.Ehrenb., Mammillaria linkei C.Ehrenb. ex Salm-Dyck, Mammillaria senilis var. diguetii F.A.C.Weber, Mammillaria senilis var. haseloffii (Ehrenb.) Salm-Dyck

Mammillaria senilis Lodd. ex Salm-Dyck is the correct and accepted scientific name for this species of Mammillaria. It was named and described by Joseph zu Salm-Reifferscheidt-Dyck* in Cactaceae in Horto Dyckensi Cultae in 1850. He cited Conrad Loddiges for being the first to name and describe the species.

*(Joseph Franz Maria Anton Herbert Ignatz Fürst und zu Salm-Reifferscheidt-Dyck)

The genus, Mammillaria Haw., was named and described as such by Adrian Hardy Haworth in Synopsis Plantarum Succulentarum in 1812.

Plants of the World Online lists 164 species in the Mammillaria genus (as of 11-30-20 when I am writing this page). Mammillaria is a member of the plant family Cactaceae with 144 genera. Those numbers could change as updates are made.


Mammillaria senilis on 11-30-20, #766-3.

I ordered this Mammillaria senilis from a seller on Ebay called Succulent Depot on November 26. It was late at night, so might as well say they received the order on the 27th. The order confirmation said I would probably receive the plant on December 3, so I was surprised when it arrived on November 30.

I knew it would be small, so when it arrived I wasn’t 100% shocked when it measured one 1″ tall x 1 1/2″ wide. It was in a 2″ pot so it still has a little growing to do before I have to ut it in a new pot. It was well well wrapped and made it to its new home safe and sound.

The plant only looks cute and cuddly, but don’t give it a hug… The long, hooked spines stuck in my fingers and I could have carried it across the floor by its spines. 🙂 White removing it from my fingers on one hand, the spines stuck in the fingers on the other hand.

Mammillaria senilis on 11-30-20, #766-4.

The Mammillaria senilis grows on moss-covered boulders in pine forests at 7800-9000 feet (2400-2800 meters) above sea level in Chihuahua, Jalisco, and Sinaloa, and southern Zacatecas in Mexico. It does not appear to have a common name, but the species name, senilis, means “of an old man”…

Mammillaria senilis is a small globe-shaped/cylindrical cactus that grows up to 5-8” tall x abut 4” wide (depending on what website you look at). It is well known for looking like a ball of cotton with long, hooked spines. This cactus branches out basally to form clumps.

Mammillaria senilis on 11-30-20, #766-5.

As with all Mammillaria species, it is covered with tubercles that are arranged in a spiral pattern. Areoles on top of the tubercles produce 30-40 very thin radial spines that are, um, 20 mm in length… That’s around 3/4”. My cactus is only 1” tall x 1 1/2” wide and looks very very odd to have such long, thin, hair-like spines. It also has 4-6 white central spines with yellowish tips. The upper and lower central spines have tiny hooks that, in case you are wondering, stick in your fingers. The axils between the tubercles also have wool and bristles, but who can tell? 

This cactus will produce orange-red flowers at some point… Well, I hope they are that color but they can also be yellowish to white. Pink is rarer, which is a good thing. Mammillaria senilis has flowers that differ from other Mammillaria species and was once placed in the genus Mamilopsis all by itself. Well, the genus was created in 1923 especially for this species, but according to Plants of the World Online, Mamilopsis senilis is a synonym along with eight other names… 

Family: Cactaceae
Origin: Chihuahua, Durango, Jalisco, Nayarit, Sinaloa, and southern Zacatecas in Mexico.
Zones: USDA Zones 10a-11 (30 to 40° F/-1.1 to 4.5° C)
Size: Maybe up to 6-8” tall
*Light: Light shade
***Soil: Very well-draining. Good quality potting soil amended with pumice (50/50) or additional perlite and chicken grit (2-1-1).
***Water: Water only when soil is dry during the growing period and basically non during the winter. This plant has a shallow root system and is rot prone…

*During the summer, I keep most of my cactus on the back deck where they receive full sun. The Mammillaria senilis may be better on the front porch with most of the succulents but I will have to experiment. During the winter most cactus aren’t picky about the light because they are basically dormant. For several winters, mine were in front of the east-facing sliding door in the dining room so they didn’t get much light but they did great. I built a new shelf for the bedroom so now they are in front of a west-facing window. Most of the succulents are on a shelf in a south-facing window in a cool bedroom but a few are in my bedroom.

**When it comes to potting soil, finding the “sweet spot” is not exactly that easy when materials are limited. Cactus and succulent enthusiasts (and experts) do not recommend using peat-based commercial mixes but what choice is there for most of us. They say to use a loam-based mix… Hmmm… Our soil is loam, so do I just use dirt? Well, no because “dirt” is heavy and you need a “light” material. There is A LOT of cactus and succulent recipes online and some get pretty elaborate. Many say to use sand as an ingredient, but if you do that, it needs to be very coarse, like builders sand, because “ordinary” sand, like for sandboxes, is too fine and it clogs up the air space between the coarser ingredients. For MANY years I used 2 parts Miracle Grow or Schultz Potting amended with an additional 1 part of perlite and 1 part chicken grit. Schultz doesn’t seem to have as many large pieces of bark. Cactus and succulent enthusiasts recommended using pumice instead of perlite and grit so I checked it out… The “guy” at General Pumice (online) recommended using a 50/50 mix of potting soil and pumice. General Pumice has 3 different sizes to choose from depending on the size of the pot. SO, in 2018 I bought a bag of 1/8″ and mixed it 50/50 with Miracle Grow Potting Soil. I liked it pretty well. Then in 2020, since most of the cactus were in larger pots, I ordered the 1/4″ size. Pumice has a lot of benefits over perlite and has nutrients that are added to the soil when watering. Pumice is also heavier so it stays mixed in the soil instead of “floating” to the top. Still, there is the issue of the mix getting very hard once you stop watering the plants during the winter when you stop watering. I think this is because of the peat in the potting soil… SO, instead of re-potting the cactus and succulents in the spring, I started doing it during the fall and winter so their soil would be loose. Since you don’t water as frequently during the winter if at all, the timed-release fertilizer does not activate. I have not tried coir, but I am looking into it…

I think a lot of growing tips online are written by people who never grew succulents and cactus. They just copy from one website and paste it to theirs. You have to sort of mimic the soil where species grow in their native habitat. For that, you almost have to go see for yourself… Typically, they grow in fairly rocky soil.

***I water my cactus and succulents on a regular basis during the summer as long as they dry out between watering. Of course, during rainy periods they seem to be fine. Since the Mammillaria senilis has a very shallow root system and needs light shade, I will put it on the front porch where it will have a roof. I barely ever in the winter (maybe a little in January) until close to time to take them back outside.

You can read my Cactus Talk & Update and Cactus & Succulent Tips to get my opinion about growing cactus and succulents.

When you bring your new plants home from the store, you need to check their roots and the soil to see if they are wet. If so, you may want to re-pot it right away. It is advisable to re-pot them in a better potting soil more suitable for cactus and succulents.

LLIFLE (Encyclopedia of Living Forms) says Mammillaria senilis is slow-growing and one of the more difficult of the Mammillarias to grow. The website says it needs a lot of light, but in areas, with intense heat and sun, it is best with afternoon shade. Information on other sites says it needs to be placed in light shade… Well, it is a neat cactus so it will be worth experimenting with. It is currently VERY small so we have some growing to do together.

There isn’t that much online about this species except mainly from websites selling it. Maybe some day there will be more.

I hope you enjoyed this page and maybe found it useful. If you have any comments, questions, or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant. If you notice I made an error, please let me know. Of course, you can always send me an email at


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