Eerily similar to the Monkey Tail Cactus, the Rat Tail Cactus produces thinner stems with fewer hary spikes on them. Because of the thin, elongated stems that droop, this cactus was named the Rat Tail cactus or Disocactus flagelliformis.
Another notable difference is that the Rat Tail features edges or ridges on the entire length of the stem.
As for the growing requirements, the Rat Tail isn’t as cold-hardy as the Monkey Tail as it cannot withstand temperatures below 40 F, but in every other aspect its care is very similar to that of the Monkey Tail.
Below, you can read my care tips and recommendations:
Size & Growth
As other cacti, the growth rate of this plant isn’t as quick, and it can take a couple of years for it to reach its mature size. When it does reach maturity, you can expect the stems to grow 3 to 6 feet in length.
The cactus produces flowers that are tubular and about 2 inches wide. It flowers in spring or early summer, producing violet-red flowers.
Flowers are short-lived, you can enjoy individual blooms for only a couple of days, but the plant puts out quite a few blooms during the flowering stage.
As a cactus, desert-like conditions are what tick every box in the requirements of this plant. Warmth and direct sunshine throughout the day is what the plant needs most.
If you’re growing the Rat Tail cactus indoors, pick a window with a south-facing or west-facing exposure, so that the plant receives all the light it can get.
In summer, keep the Rat Tail cactus outdoors, but start by slowly acclimating it to outdoor light conditions.
Ideally, it should receive about 10 to 14 hours of direct light, so find the sunniest spot you can.
As a desert plant with a tolerance to drought, you can imagine that this cactus doesn’t enjoy frequent watering with too much water at a time, in fact, frequent watering is a sure-fire way to overwater it and ultimately kill off the plant.
A potting mix that’s only slightly moist in its upper layer will work, although I’ve had more success with the soak and dry method, whereby I deeply water the soil, then wait fir it to completely dry out before soaking it again.
I’ve also experimented with watering from the bottom to encourage better root development, which is optimal to support the weight if the stems in case the plant only produces shallow roots.
A soil that drains well and it’s aerated produces the best results in keeping the roots healthy and disease-free.
The soil should contain some organic materials as well to create a rich mix that will sustain the plant in its development and growth.
A soil type that’s prone to waterlogging and compacting will not work for this succulent, so avoid those in favor of potting mixes that are light and rich in organic matter.
Temperature & Humidity
Although the plant can tolerate temperatures within the range of 40 F to 90 F, it grows best between 50 F and 80 F.
It’s not a cold-hardy cactus, let alone frost-hardy, so indoor overwintering is a must. In winter, store the plant in a cool area at around 50 F to encourage its dormancy and have the plant coming back stronger in spring.
As for humidity levels, my advice is to avoid extremes. High humidity will cause the stems to rot, a very dry environment favors pest problems, especially when indoors.
Average humidity levels are just fine for this cactus.
During the growing season in spring and summer, feed the plant once or twice a month with a fertilizer diluted at half strength.
Alternatively, you can use a time-release fertilizer once in spring to give the plant a boost in the growing season and sustain its nutrient uptake throughout the summer without shocking it.
There are plenty of options available in the market and there are even organic fertilizers designed for succulents and cacti plants, so pick one of those and apply at the recommended dose and frequency, bearing in mind that less is more to avoid over fertilizing.
Potting & Repotting
While the rat-tail cactus is still a juvenile plant, it will require repotting every year until it reaches its mature size, and then you can replant only every three years to freshen up the potting mix.
While still in active growth, nutrients in the soil need replenishing more often. When the plant matures, it no longer uses up so many nutrients.
Because of its drooping stems, a hanging basket it’s the best way to display the plant. Make sure to pick a pot that’s a size bigger with each repotting and that the pot drains well to avoid water pooling at the roots.
How to Propagate Rat Tail Cactus?
Seed propagation and stem cutting propagation are the two methods by which you can propagate the rat-tail cactus, although stem cutting propagation takes less skill and time.
To propagate from stem cuttings, you can use any part of the stem — tip or other segment. Make sure to take a cutting of at least 6 inches for a higher success rate.
Allow the cut to dry over for a couple of days, then plant it no deeper than 2 cm in a potting mix with a bit of sphagnum moss to favor rooting.
Keep the top soil moist and in a warm, sunny location, and the cutting should start producing roots in just a couple of weeks.
The Disocactus flagelliformis makes a wonderful decorative plant that requires little care yet has an impressive growth and even more impressive flowers.
Provided that you don’t overwater it and keep it in a sunny location, you can enjoy the beauty and company of this cactus for many years on end.
Not being a frost or a cold-tolerant plant, take it indoors during winter, unless you live in an area where temperatures don’t drop below 40-45 F.
Keep in a cool location (around 50 F) to allow the plant to rest and it will come back more with even more splendid blooms the next flowering season.