Last updated on August 25th, 2023 at 11:45 am
The Mammillaria plumosa, commonly known as the feather cactus, gets its name from the feather-like shape of its shoots, which makes it very appealing as an ornamental plant. Its lavender flowers are also quite lovely, making this plant suitable for both indoor and outdoor use.
Some people grow the Mammillaria plumosa indoors as an attractive houseplant while others cultivate it outdoors in the garden to adorn their landscaping or to provide color in fall and winter when not much else is blooming.
The feather cactus belongs to the family of cacti, the Cactaceae. These plants can be found in Mexico, Texas, and Arizona and they prefer dry or semi-dry soil and warm temperatures to grow well.
Mammillaria plumosa will make a wonderful addition to any collection of cacti and succulents. While not hard to care for, it does require some basic understanding of how to grow it so you can ensure it stays healthy.
Origin and distribution
The feather cactus is native to high-altitude areas of central Mexico. They occur in six different states: Zacatecas, San Luis Potosi, Hidalgo, Pueblo, Tlaxcala and Guanajuato. The feather cactus grows on rocky slopes in arid habitats from 1,500-3,000 meters above sea level (roughly 5,000 to 9,800 feet).
In a few places, mammillaria plumosa grows below 1,500 meters due to human activities. These are found near some villages and towns at the foot of mountains such as Pachuca de Soto, Huejotzingo, Atlixco, Toluca, Lerma, and Tulancingo.
In these locations, the vegetation can be semi-desert or grassland with trees like mesquite. It needs frost-free winters for its seeds to sprout. It is a xerophytic plant that does not tolerate temperatures below 10°C (50°F).
Mammillaria plumosa propagation
Mammillaria plumosa is probably one of the easiest cacti to propagate, as it will grow from either stem cuttings or by seed. Try taking a cutting from another feather cactus that’s in bloom and pushing it into some soil. If you want to start a whole new plant, simply sprinkle seeds on top of your soil layer and cover them with about 1⁄2 inch of soil; then wait for your feather cactus babies to sprout!
You can also take this opportunity to learn how much water they need: too much will rot the roots and kill your plant, while too little leaves it thirsty. You should water when the soil feels dry 2 inches below the surface; never allow your plant to sit in standing water though, as this will cause root rot.
Mammillaria plumosa care information
Mammillaria plumosa needs bright light, but not direct sun. Water regularly in spring and summer, and allow the soil to dry slightly between waterings. In fall and winter water much less often, just enough to keep from going completely dormant. Be sure to use distilled or purified water to prevent root damage.
Light requirement
The feather cactus is a very forgiving plant. It can take full sun, partial shade or even low light from an indoor grow light. Just make sure you avoid moving it around too much, as it will get stressed and not bloom properly. If you live in hot summer areas, try to keep your plant in partial shade for best results.
Soil/potting mix
Mammillaria plumosa is a very hardy plant. It grows in sandy soil, so it will do well in almost any potting mix. Choose one that does not contain perlite or vermiculite; these materials are good for use in other plants’ soil mixes, but they won’t provide enough drainage for a cactus such as a mammillaria.
The best choice is one that contains 50% peat moss and 25% of coarse sand and perlite. If you can’t find this mixture at your local garden center, the next best thing would be to buy the components separately.
Some people make their own by mixing equal parts of peat moss and coarse sand with 1 part of perlite.
If you want to make sure your mix drains properly, put an inch or two of gravel on the bottom of the pot before filling it with soil/potting mix.
Watering
Water your mammillaria plumosa once a week, only when needed. In more humid environments, water it once every two weeks. Monitor your plant’s soil to determine if it is time to water. If you feel that there is no moisture in its soil at all, it’s probably time to give it some water!
Make sure not to overwater your cactus, as standing water can cause root rot and even kill it over time. You should also make sure to discard any excess water that accumulates at the bottom of the pot; this will help prevent bacteria from forming.
Fertilizer
Like many cacti, mammillaria plumosa does best with fertilizer every couple of months. But since it’s a flowering plant, use a houseplant-specific flower food, not a standard cactus food.
Keep it simple and only use Miracle-Gro for Houseplants once per month in spring and summer and reduce that to once every three months during fall and winter. Too much fertilizer will burn your feather cactus. To avoid burning, water thoroughly before fertilizing.
Temperature
While most people assume that mammillaria plumosa like it hot, feather cactus actually prefer a more moderate temperature. They grow best in temperatures between 50 and 80 degrees Fahrenheit. With such a big difference between summer and winter, however, it’s generally easier to keep your plants indoors during winter.
Humidity
There are two main types of cacti, epiphytes, and hemi-epiphytes. Feather cactus is a hemi-epiphyte, which means it needs both air flow and humidity to thrive. To achieve proper airflow, you’ll need to allow some amount of light into your terrarium.
The ideal humidity range for mammillaria plumosa is 60% – 70%. To increase the humidity in your terrarium, set up a humidifier or use an automatic misting system that sprays water on the plant periodically.
You can also mist the plants yourself with warm water from time to time. Be sure not to get any water droplets on the leaves themselves because they may cause rot or mold issues.
If there is too much moisture in the air, consider adding more holes in the top of your terrarium for ventilation so that excess moisture can escape.
Pruning
As with most cacti, make sure to only trim off discolored, damaged or dead tissue. The general rule of thumb is that if a part isn’t growing well, it doesn’t need to be there; take it off and allow your plant to put its energy into developing new growth elsewhere.
The exception is along spine ridges, make sure you leave these intact, or else you’ll eventually end up with deformities like sagging growth areas and irregular spines.
When to repot
Repot your mammillaria plumosa annually in spring just before new growth emerges. Be sure to use a container with ample drainage holes and mix cactus soil or potting soil with 20% peat moss or vermiculite to reduce water loss.
Use a container that allows plenty of room for healthy root growth. Once the plant is planted, it will be important to maintain even moisture so the plant does not get too dry or too wet.
Fertilize once a month during the growing season with an all-purpose liquid fertilizer mixed at half strength.
Frequent watering is necessary when you are growing your plants outdoors, but be careful not to overwater indoor plants as this can lead to rot problems and fungal diseases like stem rot and root rot.
Dormancy/Winter rest
Mammillaria plumosa are one of only a few types of cacti that don’t go through winter dormancy, but you still need to provide them with some light. They can stay in their pots and be moved around as you please.
Some people choose to place them outside in direct sunlight, but I have found that they do just fine in a window that gets dappled sunlight all day long. Keep an eye on your feather cactus for signs of scorching or wilting.
If it starts looking too dry, mist it with water until the soil is damp but not wet.
Remember that plants will not grow if they are kept completely dark, so if you intend to keep your plant indoors year-round, make sure there is at least some natural light coming from a window.
The leaves will start getting dusty when they aren’t receiving enough light; if this happens, clean off the dust with a soft cloth while keeping an eye out for any sign of rot!
Mammillaria plumosa flower & fragrance
The flowers are white, pink, pale yellow, or purple, have a diameter of 6-7 mm, and appear between October and March. The feathery spines of these cacti are white to reddish-brown.
Growth rate
Feather cacti are fast-growing cacti. Typically, they grow several inches per year, depending on light and fertilizer. To maintain their compact shape, however, these cacti need to be grown in small pots and repotted regularly as they get larger.
They will eventually become large enough to divide into multiple new plants. Otherwise, their growth rate is relatively slow for a cactus (they’re not going to double in size overnight).
Toxicity
Mammillaria plumosa are non-toxic. However, like all plants, they may irritate the skin, so you should use caution when touching them. If you do touch a Mammillaria and your skin becomes irritated or itchy, be sure to wash your hands thoroughly with soap and water. If irritation persists for more than an hour or two after contact, seek medical help immediately.
USDA hardiness zones
Mammillaria plumosa thrives in USDA hardiness zones 8-11, with winter lows at or below 25°F. These cacti are not frost tolerant, so they should be brought indoors during cold weather periods.
They require little care, but the soil should be kept moist and they need to be watered regularly. The feather cactus is a true cacti treasure and can bring life to any home or garden!
Pests and diseases
Mammillaria plumosa is susceptible to a number of pests, including spider mites, mealybugs, and aphids. These are best controlled through physical removal, although mechanical and chemical means may be used as well, care should be taken as these chemicals may damage or kill other plants nearby.
Alternatively, natural predators such as ladybugs can be introduced to your garden to control pests and diseases. Regularly check for infestations by examining the stems and leaves for signs of damage.
