Mammillaria Grow Guide: How to Grow Mammillaria Cactus

Mammillaria is a genus of flowering cactus (Cactaceae) and a popular houseplant. The rounded cactus is covered in small tubercles that sprout short fine needles. (The plant’s name comes from the Latin word for “nipple” after the shape of these tubercles.) Cone-shaped pink flowers bloom from the top of the cactus in a crown arrangement.

Native to warm areas like Mexico and the Caribbean, there are over 300 species of mammillaria cactus. Other common names for mammillaria include pincushion cactus and nipple cactus.

Here are the most popular mammillaria varieties:

1. 1. Arizona fishhook cactus (Mammillaria grahamii): Arizona fishhook cactus is native to the American southwest. It is a small round cactus covered in long spines and large attractive flowers that bloom in shades of pink and white.
2. 2. Feather cactus (Mammillaria plumosa): Feather cactus has a bloated spherical shape covered in a fine white down (covering). With a resemblance to daisies, its flowers are larger than other varieties and bloom in white, pink, and yellow.
3. 3. Finger cactus (Mammillaria longimamma): Finger cactus grows a series of long, finger-like succulent pads lined with a series of central spines. Its spikes and flowers emerge from the tops of these protrusions.
4. 4. Ladyfingers cactus (Mammillaria elongata): Also known as golden stars, this variety grows in clumps of long, tubular cacti and blooms small yellow flowers.
5. 5. Mother of hundreds cactus (Mammillaria compressa): The mother of hundreds cactus grows in clusters of orbital cacti bunched together. These cacti have short needles and bright pink, bell-shaped blooms.
6. 6. Old lady cactus (Mammillaria hahniana): Old lady cactus features a fine white down of soft spines that resemble hair. Its pink flowers bloom in a circular pattern at the cactus's top, like a crown.
7. 7. Powder puff cactus (Mammillaria bocasana): This small variety of mammillaria grows in a diminutive round shape. Small, soft needles cover the surfaces of these small cacti, making them appear fluffy.
8. 8. Thimble cactus (Mammillaria gracilis fragilis): Thimble cactus grows in tight clusters of orb-like cacti, each covered in fine white needles. It blooms showy, buttery yellow flowers.

Plant mammillaria in late spring or summer to make the most of the dry, high-heat conditions that this plant prefers. Most mammillarias grow well in USDA Hardiness Zones 10–12.

If you experience cold winters, plant your mammillaria in containers so that you can transfer them inside for the cold season. These frost-tender plants will not survive in temperatures below fifty degrees Fahrenheit.

You can buy fully grown, mature mammillaria from most nurseries and gardening centers, but you can also propagate the plant from seed with this simple tutorial:

1. 1. Prepare a seed tray or small pot. Start your mammillaria seeds in a seed tray or a small pot. Keep in mind that you will need to repot your mammillaria once they begin to grow if you're using a seed tray. Fill your chosen container with well-draining potting soil (a cactus mix with perlite and coarse sand is the best), and ensure it has drainage holes. Moisten your prepared soil with water.
2. 2. Sow the seeds. Scatter your mammillaria seeds over the surface of your prepared soil without pressing them under so they can germinate. Spray the seeds lightly with some additional water.
3. 3. Wrap the seedlings. Cover your tray or pot in plastic wrap or seal it in an airtight container to help your seeds retain moisture and kick-start germination.
4. 4. Choose a home for your pot. Place your pot or seed tray in a warm place away from direct sunlight.
5. 5. Uncover the seeds once sprouting begins. When the seeds start to sprout, remove the plastic wrap or unseal the container. Leave your seedlings in sunlight for a short amount of time each day to harden them to the sun.
6. 6. Transfer into a new pot. You will start to notice your seeds growing into plants after a few weeks. Transfer your budding plants into a new pot with a well-draining soil mix if you started them in a seed tray. Keep your plants out of full sun as they continue to grow.

Once mammillaria establishes itself, it’s a low-maintenance plant that will thrive (if you avoid frost). Here are some additional plant care tips for mammillarias:

1. 1. Avoid excess water: As new plants, mammillarias require just a little water during their growing season, from spring to fall. Spray the soil around your plant with water once a week. Check to make sure that your soil is dry before you water it again. Cut back on watering during the winter. Overwatering these drought-tolerant succulents can lead to root rot.
2. 2. Keep in indirect light: Mammillarias make for excellent indoor houseplants because they prefer to stay out of direct sunlight. You can keep your cacti on a windowsill with partial shade or dappled sunlight.
3. 3. Fertilize during growth: Mammillaria plants do not require regular fertilizing once established. However, you can feed your mammillaria with fertilizer once during the initial growing phase to encourage growth.
4. 4. Monitor for pests: Mammillaria is very susceptible to mealybugs, which you may notice as white, fungal-looking fluff on your cactus. Treat them by dabbing affected areas of your plant with denatured alcohol.

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