Mammillaria, commonly known as Pincushion Cactus, is a genus of the cactus family. It is native to the deserts of North and South America and Mexico. There are about 150 recognized species in the genus, making it one of the most populous branches in the Cactaceae family.
Mammillarias are mostly small cacti, globular in shape and typically reaching heights of only 6-8 inches. But the ready growth of offsets from the areole results a clump forming habit that can increase the overall height of the plant and help it spread outwards. Some species do boast taller stems but those are rare.
The individual plants are globular, or cylindrical, and mostly covered with spines. The flowers are small and funnel-shaped, ranging in color from white to yellow to red and all the shades in between. Attractive coloration on the flowers is commonplace and increases the value of the cactus. Flower ripen into fruits that are usually red but sometimes vary in color from species to species.
Mammillaria Main Characteristics
| Common Name | Pincushion Cactus |
| Botanical Name | Mammillaria |
| Synonyms | Ebnerella, Haagea, Lactomammillaria, Mammariella, Neomammillaria |
| Family | Cactaceae |
| Type | Cactus |
| Native Range | Mexico, Southwestern United States, South America, Caribbean |
| Foliage | Evergreen |
| Propagation methods | by seeds, by offsets |
| Sun | Full sun to Partial shade |
| Soil | Well-Drained |
| Toxicity | Non-Toxic |
Mammillaria Care
The most common characteristic of these cactui is the presence of numerous, thin spines that cover the surface of the plant. The name “Pincushion Cactus” comes from these spines, which resemble tiny needles. Be careful when handling one of these spines can be a hazard, but that is the case for every cactus really. Beginners will find these cacti very forgiving and a great choice to start their foray into succulent care.
Light and Location
These cacti do best in full sun in most cases. They make a great addition to any sunny window. But during the hotter months of the year, some shade from the afternoon sun wouldn’t go amiss.
Watering and Fertilizing
Pincushion Cactus doesn’t require a lot of water. In fact, they will rot if overwatered. The key is to water thoroughly when you do water and then wait until the soil dries out before watering again. Some grit in the soil can help with drainage. In winter, reduce watering frequency.
Temperature
These are desert plants and as such they enjoy warm temperatures. During the summer months, they like warmer temperatures up to 80 degrees Fahrenheit. But in winter, they prefer to be kept under 55 degrees Fahrenheit.
Humidity
Pincushion Cactus does not like high humidity and should be kept in a dry environment. Average room conditions are perfectly fine. There is no need to make special arrangements to lower humidity unless your home is particularly humid.
Fertilizer
In general, fertilize once a month in the spring and summer with a cactus fertilizer. Stop fertilizing in the fall and winter. Balanced liquid fertilizer is recommended for most soils but your soil’s needs might differ.
Mammillaria Species
Depending on who you ask about the number of species in this genus, you’ll get a number anywhere between 150 to 300. While there is some debate on how many there really are, for the average gardener, only the most common species will be readily available from a local store.
- Mammillaria elongata – Gold Lace Cactus, Golden Stars
- M. bocasana – Snowball Cactus, Powder Puff
- M. camptotricha – Bird’s Nest Cactus
- M. candida – Snowball Cushion Cactus
- M. hahniana – Old Lady Cactus
Propagating Mammillaria Cactus
Mammillaria cactus can be propagated by seeds or offsets.
To propagate by seeds, remove the seeds from the fruit and clean them of any remaining flesh.
- Soak the seeds in water for 24 hours and then plant them in a sterile soil mix.
- Cover the pot with plastic to create a greenhouse effect.
- Keep the soil moist until the seeds germinate, which can take anywhere from 2 to 4 weeks.
Propagation by offsets is quite straightforward. These cacti produce offsets in clumps and there are plenty to choose from. To propagate by this method:
- Remove an offset from the mother plant.
- Use a sterile tool to get the job done.
- Allow the cut end to callus over for a few days.
- Replant the offset in fresh soil and keep it moist until it establishes a new root system.
Potting and Repotting Pincushion Cactus
These cacti can be potted in a variety of pots. Clay, ceramic and plastic pots are all suitable as long as there is good drainage.
When potting, use a well-drained soil mix that is specifically for cacti and succulents. You can make your own or purchase one from your local garden center.
Pincushion Cactus should be repotted every two to three years. When doing so, don’t use the same soil mix, prepare a fresh batch. Be sure not to water the succulent for a few days after its transferred to a new pot. Allow the roots to establish themselves first. If the root system hasn’t outgrown it’s current pot, there is no need to get a larger one.
Toxicity
Mammillaria cactus are non-toxic. People and pets are completely safe.
Common Pests
Mammillaria are generally pest and disease free plants. They may get mealybugs or scale but usually they are easy to get rid of. If pests like these do become a problem, treat the with a horticultural soap or an insecticidal soap.
Common Problems
Root Rot
The most common problem with Pincushion Cactus is rot. This is caused by over-watering which in turn is a result of poor drainage or a soil mix that doesn’t drain well. If your plant begins to rot, remove it from the pot and cut away any rotted tissue. Repot in a fresh soil mix and allow the plant to dry out before watering again.
FAQ
How Big Do Mammillaria Grow?
Pincushion Cactus will reach a size of 6 to 8 inches in height. Some may grow larger, depending on the species. These cacti also produce offsets that can spread indefinitely outwards in the right conditions.
How To Take Care Of A Mammillaria Cactus?
In growing season, water deeply but allow the soil to dry and feed monthly. In winter, reduce watering to negligible levels and stop fertilization entirely. Keep temperatures warm in spring and summer and slightly colder in winter to encourage blooms. Also try to keep the environments dry and place the plant somewhere sunny,
How Often To Water Mammillaria Cactus?
Only water these cacti when the soil is dry. This may only be once a week or two, depending on the species and the climate. Over-watering is the most common cause of problems with these succulents so be sure to take care not to overwater.