Mammillaria hahniana-Old Lady Cactus/Old Lady Pincushion

Mammillaria hahniana (Old Lady Cactus) on 7-19-16, #274-50.

Old Lady Cactus or Old Lady Pincushion

Mammillaria hahniana

mam-mil-AR-ee-uh  hahn-ee-AY-na

ROYAL HORTICULTURAL SOCIETY AWARD OF GARDEN MERIT

Synonyms for Mammillaria hahniana (15) (updated on 11-6-20): Mammillaria bravoae R.T.Craig, Mammillaria hahniana subsp. bravoae (R.T.Craig) D.R.Hunt, Mammillaria hahniana subsp. mendeliana (Bravo) D.R.Hunt, Mammillaria hahniana var. werdermanniana F.Schmoll ex R.T.Craig, Mammillaria hahniana subsp. woodsii (R.T.Craig) D.R.Hunt, Mammillaria mendeliana (Bravo) Werderm., Mammillaria saetigera Boed. & Tiegel, Mammillaria saetigera var. quadricentralis R.T.Craig, Mammillaria saetigera subsp. woodsii (R.T.Craig) Rogoz. & Plein, Mammillaria woodsii R.T.Craig, Neomammillaria hahniana (Werderm.) Y.Itô, Neomammillaria hahniana var. werdermanniana(F.Schmoll ex R.T.Craig) Y.Itô, Neomammillaria mendeliana Bravo, Neomammillaria saetigera (Boed. & Tiegel) Y.Itô, Neomammillaria woodsii (R.T.Craig) Y.Itô

Mammillaria hahniana Werderm. is the correct and accepted scientific name for this species of Mammillaria. It was named and described by Erich Werdermann in Monatsschrift der Deutschen Kakteen-Gesellschaft (Berlin) in 1929.

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

Plants of the World Online by Kew, there are 164 accepted species in the Mammillaria genus (as of when I last updated this page on 12-9-20). It is a member of the plant family Cactaceae with 144 genera. Those numbers could change as updates are made.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING.

Mammillaria hahniana on 5-31-17, #339-31.

I bought my Mammillaria hahniana from Wal-Mart on 2-1-16. It was in a 2 1/2” diameter (4 oz.) pot. The plant measured approximately 1 7/8” tall x 2 3/8” wide. The label states:

“Native to Mexico, forms globular stems to 6” or more in diameter. Stems are densely covered with white hair and short white spines. Concentric rings of pink flowers. Protect from frost. Provide bright light/sun. Hardy to 20 degrees F. To 6” tall. Water thoroughly when the soil is dry.”

Mammillaria hahniana on 9-5-17, #371-17.

Mammillaria hahniana is one of the more popular Mammillaria species. It can be identified by its long, thin, white hair, and wool that can become more dense with age. The species is somewhat variable, of course, and some plants may have more wool and others more hair, which has led to numerous variations and subspecies which are all considered synonyms of the species.

Plants can have different shapes when young but become more cylindrical as they grow. As with all Mammillaria species, they have small nipple-like tubercles. Being a variable species, the hair-like bristles and wool growing from their axils can be long or short, straight or curly. 

The axil, which may be hard to understand from some definitions, is basically the area between the tubercles on cactus. You have to get a magnifying glass to tell, but there can be 20 or more of these “hairs” growing from the axils. On some plants, it is very hard to tell if the hair is coming from the axil or areole… Some specimens will be densely covered with wool coming from the axils others not so much. This can make it sort of difficult to tell if you have a Mammillaria hahniana or not… 

Ahhh, the areola… Areoles are at the tip of the tubercles and is where the spines emerge. Mammillaria hahniana can have 1-4 very short central spines. In addition, there are “can be” 20-30 radial spines that are also fairly hair-like. They can be from 5-15 mm long or they may even be absent… That is just over 1/4” to a little over 1/2” in mature plants but will be even smaller when young.

Small specimens of this species may have very little wool and be very hairy so if you purchase an unlabeled cactus at a store, trying to figure out what it is can be a time-consuming project. You look at hundreds of images and you can’t just quite figure it out… 

Mammillaria hahniana with flowers on 10-11-17, #382-49.

Mammillaria hahniana is native to Guanajuato, San Luis Potosí, and Queretaro, Mexico. The species grows along relatively steep slopes in submontane matorral and deciduous forests. This cactus is locally common where it occurs, and grows in groups or clusters which are rare. Mammillaria hahniana is listed as near threatened in its native habitat because of its limited range and illegal collection. Some subpopulations are impacted by deforestation.

Mammillaria hahniana at 2 1/2″ tall x 2 3/4″ wide on 10-17-17, #384-15.

Many cacti are very slow growing so I take measurements from time to time. When I moved the plants inside for the winter on October 17, 2017, the Mammillaria hahniana measured 2 1/2″ tall x 2 3/4″ wide.

Remember to clean off your pots when you bring them inside for the winter. Remove dead leaves or other debris that might have collected in your pots and on your plants. Check for unwanted guests that may be trying to hibernate around the base of your plants because you never know…

Mammillaria hahniana from the top on 10-17-17, #384-16.

I like taking photos from the top of the cactus. Many of them grow in this neat spiral-looking pattern.

Mammillaria hahniana on 11-3-17, #389-3.

Information online says that Mammillaria hahniana is one of the fastest-growing of the Mammillaria genera and will form large groups. The wool is supposed to increase in thickness and length.

Mammillaria hahniana on 1-18-18, #401-8.

Mammillaria, like most cactus, are easy to grow if you follow a few basic rules. Check out my Cactus & Succulent Tips for my advice…

Mammillaria hahniana on 7-29-18, #487-68.

The Mammillaria hahniana is continuing to do well and is now happy on the back porch.

Mammillaria hahniana on 10-10-18, #519-46.

I had to move the potted plants inside for the winter on November 10. I always measure the cactus and succulents when I move them inside and the Mammillaria hahniana measured 2 5/8″ tall x 2 7/8″ wide. It was 1 7/8” tall x 2 3/8” wide when I brought it home on February 1, 2016.

Mammillaria hahniana on 11-29-18, #534-18.

November 29 was a nice spring-like day, so I took the cactus to the back porch for a photoshoot. I was working on a post to show the difference between the cactus in my collection.

Mammillaria hahniana close-up of the apex on 12-1-18, #535-13.

The apex is in the center of the top of the plant. Many Mammillaria species apex is kind of concave. The axil, I think, is either the lowest part or where it starts to angle up. There are 20-30 spines in this area that appear to “unfold” as the plant grows. Be it ever so sssssllllloooowwwwllllyyyy…

Mammillaria hahniana close-up on 12-1-18, #535-14.

Its white hair can cover the entire plant and increases in thickness and length as the plant ages. Each tubercle has 1-4 small central spines and 20-30 hair-like radial spines. Some specimens may not even have radial spines. Some Mammillaria species have latex in their tubercles and this one supposedly does…

<<<<2019>>>>

Mammillaria hahniana on 6-22-19, #593-28.

The Mammillaria hahniana is looking its AWESOME self on July 22.

Mammillaria hahniana on 7-4-19, #598-10.

I noticed the Mammillaria hahniana had a few buds on July 4. Its wool is wet in the above photo because we had rain.

Mammillaria hahniana at 3 1/4″ tall x 3 3/8″ wide on 10-11-19, #639-59.

I had to move the potted plants inside for the winter on October 11 because an “F” was in the forecast. As always, I took photos of all the plants and measured the cactus and part of the succulents. The Mammillaria hahniana measured 3 1/4″ tall x 3 3/8″ wide.

Mammillaria hahniana on 10-11-19, #639-60.

I really like this plant with all this wool! I wrote a Mammillaria update on November 16 which you can view by clicking HERE.

Mammillaria hahniana on 10-19-19, #643-5.

After the “F” temperatures warmed up for a few days again. This always happens. The cactus were giving me dirty looks so I put them outside for a few days. I noticed the Mammillaria hahniana had a few buds.

Mammillaria hahniana with more flowers and buds on 11-11-19, #648-3.

As long as the cactus know it is cold outside they don’t mind being inside. Most of them are on a table in front of the sliding door, so they can tell when I go in and out.

<<<<2020>>>>

Mammillaria hahniana (Old Lady Cactus) at 3 5/8″ tall x 3 3/8″ wide on 10-15-20, #747-67.

I had to move the potted plants inside for the winter on October 15 because an “F” was in the forecast. As always, I take photos and measurements. The Mammillaria hahniana did very well over the summer and now measured 3 5/8″ tall x 3 5/8″ wide.

Mammillaria hahniana (Old Lady Cactus) on 11-6-20, #755-1.

I had to take another photo of its flowers on 11-6-20…

THEN IT HAPPENED… I GOT FOOLED!

New cactus from Wal-Mart after I brought them home on December 2 (2020). I identified the plant on the right front as Gymnocalycium baldianum (Dwarf Chin Cactus), and the one in the rear on the right as Mammillaria nivosa (Wooly Nipple Cactus). The two on the left… Mammillaria ?.

I was at the Wal-Mart store in Clinton, Missouri shopping on December 2 (2020) and I needed some saucers for under the pots. They keep their cactus and succulents in a corner on a shelf, so I decided o go check them out. I won’t go into detail about their condition because they are usually pretty much neglected and overwatered. Anyway, I found four cactus that appeared I didn’t have in my collection. The terrible thing was that their labels just said “CACTUS”. How many times have I told myself ‘NO MORE UNLABELED PLANTS”? A label that just says “CACTUS” doesn’t count as a label. 🙂  Two I identified fairly easily, but the other two were not so easy. I thought the two were different species even though there were similarities. One was short and globular shaped and appeared to be a bluish-green, while the other was more club-shaped and darker green. Several thoughts ran through my mind like them possibly being the same species, you know, being “variable”. I really dislike that word…

The above photo shows the four cactus I brought home. I identified the one on the front right as a Gymnocalycium baldianum (Dwarf Chin Cactus) with no problem because it sort of resembled the Gymnocalycium saglionis (Giant Chin Cactus) I already had. I knew the other three were Mammillaria but I had no clue what species. I exhausted my brain looking at Mammillaria photos online, so I posted more detailed photos on a few Facebook groups for help. Within no time, a member suggested the plant on the rear right of the photo was a Mammillaria nivosa (Wooly Nipple Cactus) and another suggested the two on the left were Mammillaria hahniana. My thoughts, and reply, was “I already have a Mammillaria hahniana and it doesn’t look like those two plants.” Well, I had forgotten a few things… Mammillaria hahniana is a “variable” species… GEEZ!!!

Mammillaria hahniana (Old Lady Cactus) #2 (Dos) at 1 3/4″ tall x 2″ wide on 12-2-20, # 767-6.

Well, I revisited the Llifle (Encyclopedia of Living Forms Website) and looked at more photos online of Mammillaria hahniana. Of course, most of them featured their flowers and not the actual plant. But, after reading the detailed description on Llifle, I realized I had screwed up. The goal is to have more species not several plants of the same one. Once before I accidentally brought home two plants of two different species and didn’t realize it until I returned home and was taking photos. They were clearly labeled, too. But, I got over that and we are great friends now and they still joke with me about it. As I took photos and measurements of these two, however, they seemed a bit nervous. I put them on the shelf in my bedroom and put labels on the two that I found names for but not theirs. They really were getting more nervous because they knew they were Mammillaria hahniana and their new foster dad didn’t know it yet or didn’t want to face it. I think they were beginning to realize that I thought I screwed up and thought they had fooled me… Once I came to the conclusion that these two plants were indeed probably and very likely Mammillaria hahniana, I was fine with it. Fine because I now have three different plants of the same species that show how they can be variable… I just named them #2 and #3. Maybe I should give them the Spanish names dos and tres.

In the photo above, you can see this plant is very hairy with more of a dark green color and is club-shaped. The plant measured 1 3/4″ tall x 2″ wide.

Mammillaria hahniana (Old Lady Cactus) #2 (Dos) on 12-2-20, # 767-7.

From the above close up, you can see hairs, wool, and spines. There is just a little speck of wool growing from the axils between the tubercles. Some of the “hair” is also coming from the axils but you have to get a magnifying glass to tell. The areoles on the tip of the tubercles have 1-4 very short central spines and 20-30 hair-like radial spines… Some are very short and others VERY LONG. Information on Llifle says these hair-like spines can be from 5-15 mm long which is just over 1/4″ to just over 1/2″. Some of the longer hairs on this plant are nearly 1″ long which I think are coming from the axils. Dos has more of a flat top similar to Unos…

Mammillaria hahniana (Old Lady Cactus) #2 (Dos) on 12-2-20, # 767-8.

The apex of Dos (#2) is clearly concaved with a lot of wool in the center. The areoles also have more wool around the top of the plant but seem to disappear somewhat farther down the stem (as the plant grows).

Mammillaria hahniana (Old Lady Cactus) #2 (Dos) on 12-2-20, # 767-9.

The top of cacti really fascinates me for some reason. It’s like the tubercles are arranged in a spiraling pattern… In the above photo, you can see the central spines are kind of whitish color with reddish tips.

Mammillaria hahniana (Old Lady Cactus) #3 (Tres) at 1 1/8T tall x 2″wide on 12-2-20, # 767-10.

Tres is shorter than Dos at 1 1/8″ tall but it is also 2″ in diameter. When I measure cactus I ignore the spines and focus on the body (stem) of the plant. Tres is kind of squat and globe-shaped like a pumpkin. It is kind of more bluish-green in color which can throw you off a little… The Mammillaria muehlenpfordtii in my collection is a bluish-green and AWESOME!

Mammillaria hahniana (Old Lady Cactus) #3 (Tres) on 12-2-20, # 767-11.

Tres has A LOT more and larger tufts of wool in its axils, especially around the top, and its hair is not as long.

Mammillaria hahniana (Old Lady Cactus) #3 (Tres) on 12-2-20, # 767-12.

From the top, Tres looks A LOT different than Dos. The concaved apex is barely visible from all the wool. The hair-like radial spines and axil hair give Tres a cobwebby appearance.

The Mammillaria hahniana trio. Unos in the back, Dos on the right, and Tres on the left on 12-5-20, #768-1.

Once I came to the conclusion that it was definitely possible the two new Mammillaria were M. hahniana, I took all three plants to the back porch for a photoshoot. I brought Unos home from Wal-Mart on February 1, 2016, when it was just 1 7/8″ tall x 2 3/8″ wide. On October 15 (2020) when I moved the plants inside it measured 3 5/8″ tall x 3 5/8″ wide.

Mammillaria hahniana Unos, Dos, and Tres from the top on 12-5-20, #768-2.

From the top view, Unos, Dos, and Tres look nothing alike. You can certainly tell how someone would think they are three different species. Am I sure they are all three Mammillaria hahniana? NOPE!

I sent an email to an expert with photos of all three but I have not heard back from him yet.

USEFUL INFORMATION:
Family: Cactaceae
Origin: Mexico
Zones: USDA Zones 9a-11 (2- to 40° F)
Size: Small, maybe about 4-5” tall x 4” wide
*Light: Sun to part shade.
**Soil: Fast-draining. Potting soil amended with additional pumice and chicken grit or 50/50 potting soil and pumice.
***Water: Average during the growing period, not necessary in winter.

*During the summer, I keep most of my cactus on the back deck where they receive full sun. 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 but 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 repot it right away. It is advisable to repot them in a better potting soil more suitable for cactus and succulents.

I really enjoy the Mammillaria hahniana and I will keep adding more photos and information as time goes by. Having three in my collection that look nothing alike will be very interesting…

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.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
LLIFLE (ENCYCLOPEDIA OF LIVING FORMS)
DAVE’S GARDEN
CACTUSGUIDE
ROYAL HORTICULTURAL SOCIETY

2 comments on “Mammillaria hahniana-Old Lady Cactus/Old Lady Pincushion

  1. I love this one! Those little flowers are so pretty!

    Liked by 1 person

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