Last updated on August 25th, 2023 at 11:45 am
Mammillaria cactus, also known as the pincushion cactus, is one of the most popular types of succulents in the world. Their low-maintenance requirements, charming round shape, and clusters of pink or red flowers make them a very attractive choice for hobby gardeners and landscapers alike.
These cacti are considered easy to grow, even by beginners, but they require some care in order to keep them healthy and growing strong. Luckily, with just a little bit of information on how to take care of your pincushion cactus, you can guarantee it will stay pretty and healthy while you enjoy its blooms year after year.
Pincushion cactus need careful attention to water and light to thrive. These low-light houseplants are not true cacti but instead belong to the family Cactaceae, which also includes chiles and epazote (a plant used in Mexican cooking).
If you are looking to buy your first pincushion cactus or add more to your collection, be sure to follow these guidelines when caring for your beloved pincushions.
Origin and distribution
Pincushion cactus originate from the mountainous regions of Mexico and are now available all over the world in many different colors and shapes thanks to modern breeding techniques.
They are native to northern Mexico and the Southwestern United States and can be identified by their tubercles (small bumps on the stem) and their spherical shape. Pincushion cactus grow slowly from 1 to 2 inches per year and can live up to 50 years if they receive proper care.
Pincushion cactus propagation
There are two methods of propagating pincushion cacti: from seeds and from stem cuttings. Propagation is necessary because these plants do not reproduce sexually.
Therefore, in order to produce new pincushions, you must use asexual reproduction by means of cutting or seed. Although it can be frustrating at times, propagating pincushions is easy once you know how to do it correctly.
The best time to take cuttings is during the summertime when they are more vigorous. Make sure that the cuts heal before planting them. Keep the soil moist but never soggy.
Pinch off any dead parts of the plant as needed. If grown indoors, place your plant near a window with good sunlight exposure for 12 hours each day. Allow one side of the potting medium to dry out before watering again.
Pincushion cacti prefer full sun exposure outdoors so make sure you don’t put your plant in too shady an area.
Pincushion cactus care information
Pincushion cactus plants are considered low-maintenance plants and require little care once they have adjusted to their new environment. During their first summer after transplanting, do not water your pincushions more than once every few weeks.
Pinch off yellowed or damaged tissue as needed. Repotting can be done at any time of year; simply choose a pot one size larger and fill it with cactus soil or regular potting soil mixed with sand or perlite to improve drainage.
Pincushion cacti need a lot of light, and therefore should be planted in an area that gets at least five hours of direct sunlight each day. Placing them near a large window or sliding glass door is ideal.
If you can’t provide enough natural light, placing them under grow lights is fine. They also need plenty of air circulation to remain healthy, so make sure your pincushions are placed somewhere with lots of fresh air flow.
The best soil mix for your pincushion cactus is one that drains well but holds water at the same time. A 50/50 combination of sand and potting soil should work just fine. Be sure to choose a pot with holes in it, this will help it drain faster.
Overwatering is a common mistake that kills pincushion cacti. Water them when they’re relatively dry, and only until their soil is damp. Make sure to use room-temperature water so it’s not too cold for your plant. Another consideration: use soil instead of cactus mix or other potting mixes with added fertilizer, which can build up over time and burn your plant.
If you want your pincushion cactus to thrive, water it less frequently but more thoroughly. Once a month is perfect. It’s essential that you don’t allow your plant to dry out, so watch it carefully and make sure that water doesn’t sit in its pot for too long.
If using tap water, let it sit overnight to remove chemicals like chlorine and fluoride; if using bottled water, make sure that no minerals have built up on top of the soil.
Over-watering these plants can cause rotting of the roots and crown.
To keep your pincushion cactus in good shape, you’ll need to fertilize it every two months during spring and summer with a balanced liquid fertilizer. In winter, feed plants just once since they’re semi-dormant at that time of year.
Follow package directions carefully when using chemical fertilizers and only add fertilizer to water; never directly onto plant leaves or stems. If you don’t have access to balanced liquid fertilizer, use an all-purpose houseplant food.
Pincushion cactus requires warm temperatures, between 60 and 80 degrees Fahrenheit. Higher temperatures can kill your plant, but if you’re growing it indoors, keep a careful eye on it; if you notice any wilting or discoloration of foliage at all, move your pincushion to a cooler spot immediately.
That said, don’t leave your pincushion in cold drafts either; drafty windowsills are bad news for these plants.
Mammillarias, like most cacti, are highly dependent on humidity. These cacti should be watered only when their soil is dry to the touch. Under-watering these plants can cause them to quickly lose their fleshy leaves and develop unsightly spotting.
Mammillarias will thrive in a humid environment with 60-70% relative humidity.
Pincushion cacti may look like they are covered in big, fat needles, but they are actually small and soft. They can be cut with any sharp pair of scissors to create pruning cuts that don’t harm them.
When making these cuts, try to keep as much green tissue as possible and stay away from cutting into buds or flowers that may be forming on your plant.
When caring for your pincushion cactus, you’ll have to pinch out its growing tip (or tips) from time to time. Make sure to leave about an inch or two of stem on each side before pinching them off.
Once these are removed, use clean tweezers or needle-nose pliers to do so, as this will prevent any bacteria from getting into the wound.
You can also prune off all excess stems after this process by simply cutting them off close to the base with a sharp knife or scissors and then remove any spines left behind on these cut stems with a small brush before replanting them back into their container.
When to repot
Pincushion cacti should be repotted every 1 to 2 years. Wait until new growth appears, and then remove it from its current pot. Repot your cactus into a larger container with fresh potting soil and place it in a warm, sunny location. Keep the soil slightly moist but not soggy.
Check your plant every day, and water as needed. Never let it sit in water! Be sure to feed pincushion cacti regularly with a balanced fertilizer throughout the year. In late winter or early spring, prune any dead stems from previous seasons away from the plant’s center. The best time for this is just before you fertilize for the season.
Pincushion cacti go dormant in autumn and grow new tubercles each spring. During winter dormancy, they’ll lose their leaves, but it’s important to know that these plants are still alive and only going into a resting phase.
You may water a pincushion cactus during winter dormancy, but make sure to stop watering once all new tubercles appear. Once your plant begins growing again in spring, you can continue regular watering practices.
Pincushion cactus flower & fragrance
Pincushion cacti are also known for their bright and fragrant flowers, which often appear in late summer or early fall. In other parts of the world, pincushions blossom throughout spring and summer.
The blooms have four showy white petals with a purple center. The petals measure about one inch long by 1/2 inch wide. The flowers emit a pleasant scent similar to jasmine that can be smelled up to 10 feet away!
Pincushion cacti can grow to a few inches high and wide over a couple of years. It will then stay at that size for several years before forming pups or babies around its base. These new plants are clones of their mother plant, so it is recommended to remove them from their original pot and repot them in an identical-sized container with fresh soil.
The pincushion cactus plant is considered poisonous. Children and pets should not be around it because they may eat parts of it, which will cause health issues.
Even adult humans should take care when handling these plants. Don’t rub your eyes, mouth, or other sensitive areas after you touch one. Wash your hands immediately if you do come into contact with any part of a pincushion cactus plant and keep it out of reach from children or pets.
USDA hardiness zones
Pincushion cactus thrives well in USDA hardiness zones 9 through 11. When planting, the soil should be dry and should be planted 2 inches deep with 2 to 3 inches of space between plants.
Pests and diseases
These plants are relatively healthy, but they are susceptible to a number of pests and diseases. The most common pest is scale insects, which often go unnoticed until they cause serious damage.
Mealybugs and aphids can also be a problem for pincushion cactus plants, although both are easy to get rid of. Overwatering your plant can also lead to root rot, so make sure it’s never sitting in excess water or sitting in waterlogged soil.
The care level for pincushion cacti varies depending on the species. Check with your local nursery for care information specific to your plant. All species require well-drained soil and shelter from direct sun, excessive rain, and prolonged drought.
Cacti do not like having their root system disturbed, so planting is best done in containers. Your cactus will thrive if you water it properly, feed it with the right fertilizers, give it the appropriate amount of light and air circulation, and repot when necessary.