Common name: Rose Pincushion Cactus, Rose Pincushion, Pink Crown, Nipple Cactus, Fishhook Cactus
Synonymous: Mammillaria crinita
Distribution and habitat: Mammillaria zeilmanniana is a cactus endemic to Mexico. Its natural habitat the daytime temperatures are quite high and the nights are cool. It grows on steep of volcanic rock (igneous) face in canyon walls in semi-desert and deciduous forests.
Description: Mammillaria zeilmanniana is one of the most beautiful Mammillaria. It is an exception from the general rule that red-flowered cactus of this genus do not bloom until they are several years old. It produces a profusion of deep carmine-red flowers while still quite young and small.
The young cactus is solitary but slowly forms a cluster of individual nearly globular stems, which are glossy green and usually about 6cm (2.3 inch) high and 5cm (2 inch) across. A four-year-old specimen is likely to fill a 10cm (4 inch) container. The tubercles are 6mm (2.3 inch) high and each areole has 15 to 18 radial white and 2 to 4 central brown spines, all about 1-2cm (0.4-0.8 inch) long. One of the centrals is hooked.
Mammillaria zeilmanniana flowers during the summer sometimes followed by brightly coloured fruits. The flowers, placed in circle close to the apex, originate from the aureola at the base of the tubercles, bell-shaped, with a diameter of 1.8-2 cm (0.7-0.8 inch) and keep open for almost one week; the blossoming lasts the whole summer.
Houseplant care: Mammillaria zeilmanniana is a small growing, but easily flowering species. When grown outside it likes full sun or afternoon shade, when grown inside it needs bright light and some direct sun.
Plant has spines; use extreme caution when handling.
Light: For attractive coloured spines and good flowering, give Mammillaria zeilmanniana direct sunlight all year long.
Turn regularly the Mammillaria zeilmanniana to ensure that growth is even.
Temperature: During the spring and summer active growth period, normal room temperatures are satisfactory for these cacti, but they do best if kept in a sunny position outdoors during these months. Good ventilation is essential for their health.
It is important to give Mammillaria zeilmanniana a winter rest at about 10°C (50°F) if possible. If necessary they can survive a minimum temperature of 5°C (41°F).
Watering: In spring and summer water moderately, just enough to make the potting mixture moist at each watering, but allowing the top centimetre (0.4 inch) or so of the mixture to dry out before watering again. As cactus begin to form clusters, care should be taken to not allow the excess of water to remain on the surface of the mixture between the stems. Puddles of this sort can easily cause rotting. For this reason, it is a good alternative to water Mammillaria zeilmanniana from below. To do this, stand each pot in a pan containing 5cm (2 inch) of water and leave the pot there until the surface of the potting mixture has become moist to the touch. Leave the pot in water for two or three minutes once a week.
During the winter rest period give only enough water to prevent the mixture from drying out.
Fertilising: A long-term slow-release fertiliser should be incorporated into the potting mixture. If this procedure is carried out, no other feeding should be necessary.
Otherwise, give fortnightly liquid feed with high-potassium fertiliser in the growing season only. Alternatively, use fertiliser specially formulated for cacti.
Potting and repoting: Use a potting mixture consisting of one part of coarse sand to three parts of either soil or peat based mixture. Cactus that form large clusters do better in a broad pan than in a pot. A cluster of 8cm (3 inch) across needs a 10cm (4 inch) pan. Mammillaria zeilmanniana are best grown in a terracotta type pot which should have at least one drainage hole in the base and it should be unglazed. This type of pot allows good drainage and allows the compost (therefor roots) to breath.
Solitary specimens or those with only a few branches or offsets may be grown in an ordinary pot; an 8cm (3 inch) pot will suit a cactus 5cm (2 inch) across.
Repot Mammillaria zeilmanniana in early spring. Carefully remove each cactus (or cactus cluster) from its container, lifting the cactus by holding it near the base with tongs or forceps. Gasp these cacti with special caution, because the hook can be difficult to remove, if it catches in anything (such as clothing) without tearing away the areole.
If roots have filled the present container, move the cactus into a slightly larger one. Otherwise, gently shake away as much as possible of the old potting mixture and replace the Mammillaria zeilmanniana in original container, after it has been thoroughly cleaned. Add fresh mixture as necessary.
Propagation: Mammillaria zeilmanniana are raised from seed. Remove the berries produced after the flowering season in autumn. Squeeze the pulp containing the seeds onto a piece of blotting paper and put the paper in a dry, sheltered place for several days to dry off and preserve them safely for sowing season. Then pick off the seeds and store them in labelled envelopes until sowing time during the following spring.
Clustering cactus can also be propagated from branches or offsets during the spring and summer months. This is the quickest way to produce a flowering-size cactus. Carefully cut away a branch and allow it to dry for several days. Then gently push the cut end into the surface of a 5 or 8cm (2-3 inch) pot of standard potting mixture.
The easily detached offsets of some species do not even need to be dried, but can be potted up without delay. Treat newly potted branches or offsets in the same way as recommended for mature Mammillaria zeilmanniana; they will root within a few weeks.
Discoloration of the top of the cactus or collapse of the stem may occur if the cactus is incorrectly watered.
Mealy bugs and mites can be a problem.
Treatment: Mealy bugs are also quite difficult to get rid of and is nearly impossible to do so without the use of a systemic pesticide. Since mealybugs affect different areas of the plant, it is always wise to check the entire plant when mealybugs are detected (check down in the joints of the plant and take the cactus out from its pot to inspect the roots). For best results, after physically removing the mealybugs with a toothbrush or high pressure water spray, it is best to treat the plant with a systemic insecticide. This should be applied only when the plant is growing or it will not be taken into the plant tissues. It is also a good idea to treat you cactus at the onset of the growing season to prevent mealybugs from getting a start.
If you even suspect spider mite damage on your cacti, quarantine all infested plants immediately. Treatment with some form of pesticide is the only cure. It is best to look for a pesticide that specifically states control of spider mites on the label. Multiple treatments will be required as the eggs will not be killed by the pesticide. Since most pesticides will create a phototoxic reaction on the cactus epidermis, it is best to keep your plants out of direct sunlight after treatment for several weeks. Finally, it is also a good idea to spray the areas surrounding the infected plant and to pay close attention to uninfected plants. The chances are good that the spider mites have been on the move before you noticed them.
Uses: Mammillaria zeilmanniana is an excellent cactus for container growing. It remain small enough all its life to be grown on a sunny window-sill. It is an easy to grow plant and flower reliably year after year.
Foliage – green
Features – flowers and fruits
Shape – globular
Height: 6cm (2.3 inch)
Watering in rest period – sparingly
Watering in active growth period – moderately
Light – direct
Temperature in rest period – min 4°C max 13°C (39-55°F)
Temperature in active growth period – min 16°C max 24°C (61-75°F)
Humidity – low
Hardiness zone: 9a-11