Mammillaria Plumosa Care: How to Grow Feather Cactus

Mammillaria plumosa (mam-mil-AR-ee-uh plum-OH-suh) is a member of the plant family Cactaceae (kak-TAY-see-eye) hailing from Nuevo Leon, Mexico. The plant is commonly referred to as Feather Cactus because of its soft, downy appearance.

In its native environment, Mammillaria plumosa is a perennial. If planted outdoors away from its home desert, these cacti are best used as annuals. Kept indoors, or brought indoors during cold weather, they will live for years.

feathery looking spines of Mammillaria Plumosa cacti
Feather Mammillaria cactus

Feather cactus can grow outdoors year-round in the southwestern United States and in northern South America.

Mammillaria Plumosa Care

Size & Growth

The spiny Mammillaria plumosa cacti may grow into a columnar or spherical form, usually in clusters. They have multiple prominent tubercles with flowers growing in a ring at the top of the stem. 

These low growing cacti attain their ultimate height of about 4” inches and cluster width of about 3.5′ feet in a 5 to 10 year time period.

The soft, feathery looking spines of feather cactus Mammillaria plumosa start out as very pure white in color, but they can become dusty and stained with the passage of time. 

It’s important to understand that even though Mammillaria plumosa looks soft and cuddly, it is not. The longer feathery spines on the surface are not especially pointy, but just under them are younger, shorter ones that are quite sharp.

Flowering & Fragrance

The ring of flowers that grows around the top of the cactus is made up of daisy-like blooms. 

These blossoms are very strongly and sweetly scented. They may vary in color with some being ivory, others off-white and some pink. 

They are extremely attractive to hummingbirds, bees, butterflies and other pollinators.

Light & Temperature

The desert Mammillaria plumosa feather cactus needs a great deal of bright, direct light. If you’re keeping your cactus as a houseplant, place it in a southern or western facing window. 

You may also need to supplement the light with a grow light.

Be careful not to put your Mammillaria into direct full sun as soon as you get it. Start out with it in bright, indirect sunlight and transition it to a full sun location gradually.

Kept outdoors, Feather Cactus likes a sheltered location and direct sunlight through most of the day, but it will appreciate light shade in the afternoon. 

Be aware that excessive amounts of shade will cause the plant to grow fewer spines, and it will lose its bluish green color.

Mammillaria plumosa feather cactus is winter hardy in USDA hardiness zones 9a to 11b and from 20° to 50° degrees Fahrenheit.

Watering & Feeding

As with most cacti, excessive watering will cause your feather cactus to rot. 

During the hot months of summer, water regularly, but be sure that the Mammillaria plumosa feather cactus never stands in water. Use a sharp well draining soil, and allow all excess water to run off every time you water.

If kept outdoors in an area that gets a decent amount of rain, you may not need to water at all. If kept indoors, your watering schedule will vary depending on your indoor conditions. 

If your home is quite hot and dry, you may need to water every couple of weeks. If you have a higher level of humidity in your home, you may need to water every six weeks. 

Feel the soil. If it is completely dry, it’s time for thorough watering.

Apply slow release fertilizer once a year in the springtime, or provide a weak feeding of a good complete liquid fertilizer once early in the spring and again in midsummer. 

Mix at about a quarter or half the amount recommended on packaging instructions.

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Soil & Transplanting

When keeping your Mammillaria as a houseplant, use a high-quality, well draining cactus or succulent mix.

Outdoors, work a high percentage of coarse sand and/or fine gravel into the soil to provide the drainage that your Feather Cactus needs.

These cacti are not picky about pH levels and can do well in acidic, alkaline or neutral soil.

Plumosa does not need to be repotted frequently, and you can simply provide your plant with a slightly larger pot and entirely fresh substrate every couple of years.

Grooming & Maintenance

Mammillaria is a very low-to-no maintenance plant. No pruning is necessary. You may occasionally need to separate offsets into new pots.

How To Propagate Mammillaria Plumosa

Plumosa Mammillaria cactus can be propagated by removing offsets as they appear and planting them in their own pots to be treated as mature plants.

You could also divide your plant when you repot if there are lots of offsets.

If no parent plant is available, you can propagate Mammillaria cactus by seed sown indoors, early in the springtime.

Mammillaria Plumosa Pests or Diseases

If watered correctly and kept in sharply draining soil with plenty of bright light and good air circulation, your Mammillaria plumosa feather cactus should have few or no pest or disease problems.

Overwatered plants kept in substandard conditions are subject to attack by mealybugs. Overwatering also causes fungal infections and rot.

More on Succulent Pests Control

Is Plumosa Considered Toxic or Poisonous?

These cacti are not toxic but remember they are also not soft and cuddly. Keep your Mammillaria out of the reach of kids and pets to avoid uncomfortable injuries.

Is Plumosa Considered Invasive?

Plumosa cacti is a bit challenging to grow away from their native desert setting. For this reason, they are not invasive.

Suggested Uses For Mammillaria Plumosa 

Away from the desert, these attractive cacti are best kept as container plants. 

They make an interesting houseplant that can be moved outdoors to the deck or patio in the summertime.

In a very warm setting, your Mammillaria may do well as an addition to your rock garden or cactus garden. If you live in a desert, these cute cacti make a pretty addition to your butterfly and pollinator garden.

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