The name Mammillaria comes from the Latin "mammilla," which means "nipple." In fact, many of the species produce a milky sap which is released at the slightest injury. Mams differ from other cacti by having their mammillae or tubercles distributed all over the surface instead of being arranged in the form of ribs, and in the way that their flowers are produced. Whereas the flowers of most cacti grow from the areoles (remember those small tufts of hair where cactus spines are produced?), in Mams these grow from the axils, i.e., from the space between the mammillae.
Unfortunately, I don’t have any pictures of flowering Mams in this edition. Johann Espiritu took these photos in early September, and none of the Mams were flowering during the photo shoot day. Most Mams normally produce their blooms from March to August, following their internal "nature clocks" from their native North American habitats.
While the Philippines is near the Equator, we are still technically considered part of the Northern Hemisphere. And the way cactus plants behave – at least in my collection – follows their behavior in the wild. A few Mams do flower after August. I just checked the greenhouse and noted three Mams flowering – M. schiedeana, M. collinsii and M. camptotricha forma albescens. And I know that M. plumosa will surely flower come November-December. Too bad none were blooming when Johann was around.
Whether flowering or not, the outstanding features of these plants have to be their symmetry, spination and color. Many feature almost perfect precision in their spine arrangement, and the spines are often strongly colored. Mams are a fairly small cacti, usually globular, but a few may become columnar to elongated when old. Some cluster while others stay solitary. Not many grow to more than five inches wide or more than eight inches tall. As such, quite a large collection can be accommodated even in a small space focuses. Many cactus growers have concentrated on Mams and have built up beautiful specialized collections. In fact, there are international societies like The Mammillaria Society based in the UK, which focus only on the study of Mams and allies.
It is rare to find a succulent collection without a few Mams represented. The genus has enthusiasts, whether these be beginners, one-off fanciers, or seasoned and specialized growers. The vast majority of species make no special cultural demands. However, as the genus covers a vast area in terms of natural habitat and embraces many different species, it is difficult to provide growing notes which are generally applicable. There are many Mams which are very easy to care for, not too demanding in their requirements. However, there are those species which are quite the opposite, requiring more careful attention and providing a nice challenge to the more experienced collector.
Getting back to generalities, one other very crucial consideration is the microenvironment each grower can offer his/her plants. The microenvironment consists of many factors, including the location where one houses the plants and how the sunlight impacts on this location year-round; the type of soil or growing medium used, the type of pots one uses, whether these are clay/porous pots, plastic, or some other medium, the type of water one has, etc., etc. In Metro Manila, one has to unfortunately consider the level of pollution as well. I intend to discuss these very important topics in a series of future articles. Suffice it to say for now that each grower has a unique microenvironment to offer. And this unique microenvironment determines the growing regimen and techniques used for successful culture. A cultural regime that works well for one may be a total disaster for another. What might be an easy plant for one to grow may be an extremely difficult plant to grow for another.
Bearing all these in mind, let me present a few Mams which will hopefully give the reader an appreciation for the beauty and variety of this genus. I also have some brief cultural instructions, based on my experience. Keep in mind that I grow my plants in plastic pots, which take a lot longer to dry out than clay pots. I hope to write more specialized articles on Mams in the future, but for now, the goal is to build an overall understanding of these gems of the plant kingdom.
Before proceeding, however, a further word on microenvironments. With very few exceptions, Mams, like many cacti, come from dry, temperate climates which have generally cool nights and a cool winter resting period. So growing these plants in our tropical, 100% humidity, hot days and warm nights type of environment provides an extra challenge to the grower.
The closest to a temperate climate that I have come across here is in the Baguio/Benguet area, followed by Tagaytay. The cool nights in these areas are, I believe, very important for flowering of cacti. There you will see many Mams and other cacti flowering and thriving vigorously. Metro Manila doesn’t have the cool nights and lower humidity levels of Baguio. You may see a drop in flower production here, maybe even no flowers will be produced. But with good care, the plants will still thrive vegetatively, producing good growth and exquisite, colorful spines.
M. bombycina – My very first Mam, but funny thing because this is not one of the easier plants. This plant from Mexico has a bluish green body and magnificent spination, with a very strong hooked spine you don’t want to get entangled in. It forms clumps in time, requires full sun and very careful watering (i.e., wait for the growing medium to completely dry out before watering again).
M. camptotricha – Another Mexican Mam (as most are) known as the "Bird’s Nest" cactus because of its interweaving spination. It requires full sun to keep the spines tight but can take more water. It is one of the easier Mams to grow and can be oftentimes found in the plant stores locally.
M carmenae – One of my favorite Mams (and also my mother in-law’s) because of its yellow sprays of fine spines (yellow being my favorite color, Carmen being my mother in-law’s name). It was discovered in 1953 but was lost and rediscovered in 1976. In its native habitat in the Sierra Madre in Mexico, it grows amid pine needles beneath scattered pine trees. It is a vigorous grower and eventually clumps. It is an easy Mam to care for, flowering profusely in Baguio but quite reluctantly here in Manila.
M. chionocephala (ritterana) – A beautifully-black spined Mam from Coahuila and Durango, Mexico, with a lot of white wool covering the body. It is globular but becomes somewhat columnar with age. It requires full sun and careful watering.
M. guerreronis – Named after its endemic habitat, Guerrero, Mexico, it can reach a height of over two feet with age and a diameter of over two inches. It is probably the tallest growing of the Mams, densely covered with pinkish-tipped spines. It requires full sun.
M. herrerae – One of the most beautiful of all Mams, this is also one of the more difficult to rear in the tropics. Full sun and very careful watering is required, only a little water at a time is given in my growing conditions. It has large, beautiful reddish violet flowers, if it can be coaxed into flowering in Manila. It forms beatiful white clumps in time. It remains one of the rarest and most desirable of all Mams.
M. lasiacantha – Another beautifully-spined Mam, this one is from Texas and northern Mexico. The plant depicted is beginning to branch. To maintain the compact growth and spination, the plant requires full sun and average watering.
M. lauii fa. lauii – This plant is from the high altitudes of Tamaulipas, Mexico. It is a massive clump former requiring full sun and average watering. I have seen this plant flowering profusely in Baguio, but while it has put out strong vegetative growth under my care, it has refused to flower without the cool nights.
M. lenta – This is another temperamental plant, but if given the right conditions, it will reward you with its beautiful spine formations. The plant depicted is an old specimen which has been with me for a number of years now, producing strong vegetative growth each year but, alas, refusing to flower. Careful watering and good sunlight are a must.
M. luethyi – A newly discovered Mam, when Johann first saw this plant up close, it reminded him of some black exotic underwater coral. All the plants I have seen of this species are grafted, not just to speed up growth but on its own roots, the plant may be quite sensitive. In our tropical climate, it grows vigorously and pups profusely and, so far, it has proved a relatively easy plant to rear.
M. nivosa – This is one of a very few tropical growing Mams endemic to the West Indies. Because of its tropical nature, growers in temperate climates have some difficulty with this plant. In Manila, however, it is very easy to grow and a rewarding plant to have, flowering readily over the summer and being able to take in more water than other Mams. The plant depicted also shows the typical red fruit produced by Mams.
M. pennispinosa v. nazasensis – This is a beautiful, feathery-hooked species from Mexico which also requires very careful treatment for it to look its best. It will readily rot if given too much water, and it requires strong sunshine to keep its compact growth.
M. perezdelarosae – Another of my favorite Mams, this one was also fairly recently discovered and is a cousin of M. bombycina, but with more beautiful spination in my biased opinion. Full sun and very careful (i.e., little) watering is required to keep the plant’s growth tight and to prevent elongation of the stem.
M. plumosa – The feather ball cactus because of its white feathery spines, it is one of the favorite cacti of many growers. Given full sun and careful watering throughout the year, this plant should never fail to reward the grower with its pale yellowish flowers at the end of the year, around November to December. It is one of the few cacti still flowering so late in the year. Best not to water the plant body but just around the base of the plant, to preserve the beautiful feather spines.
M. pringlei – This egg-shaped Mam with long curling yellow spines is from San Luis Potosi, Mexico and is a relatively easy plant to care for. It does require strong sunlight to encourage the true growth of the very decorative spines. It normally flowers in late summer, producing brilliant carmine red flowers.
M. senilis – This is another difficult Mam for me, susceptible to rot if given too much water. But with full sun and just a little water, it will produce beautiful white spines which gives the plant an overall white appearance. But beware of the central spine which is hooked. I have seen this plant flowering in Baguio, a most beautiful orange red flower that is different from all other Mams. Because of this flower, this plant was once classified in a separate, monotypic genus, Mammillopsis.