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If you’ve ever wondered how to tell the dog tail cactus and rat tail cactus apart, you’re not alone! They are close enough in appearance that you could mistake one for the other at first glance.
However, with a closer look, you can spot some distinctive differences that set them apart. So what are the differences between them?
The dog tail cactus is larger than the rat tail overall. It has thicker stems and tends to grow more upright initially, before cascading downward, whereas the rat tail has cylindrical stems and a trailing growth pattern. The dog tail prefers a more humid habitat while the rat tail prefers drier climates, although it’s adaptable.
Here’s what I’ve learned about these two cactus plants and how to identify one from the other.
Differences Between Dog Tail and Rat Tail Cactus
As I mentioned, at first glance these two plants look very similar but on closer inspection, some very distinct differences will help you in identifying them.
Differences such as the size and looks of the spines, the thickness of the stems, and how sturdy the stems appear become very apparent.
For example: The rat tail cactus plant, as a whole, is a little smaller than the dog tail cactus, letting you fit it into slightly smaller spaces. This is something to keep in mind if you are growing it indoors, especially if your space is limited.
There are also differences in their overall shape, how they grow, differences in the size and color of their flowers, and even the time of day or night that they bloom which is explained further down.
Appearance
In terms of appearance, the dog tail cactus, Strophocactus testudo, has thicker and more robust stems compared to the stems of the rat tail cactus, Aporocactus flagelliformis.
The dog tail cactus grows upright initially before cascading downward, and its stems can reach up to 9-10 feet in length. It mostly grows to these longer lengths in the wild, but will likely not grow this long when grown in containers.
It grows well as a hanging plant.
Its stems also like to climb and twist around any support it can find. In the wild, it would wrap around the tree branches where it is growing. When you look at a stem, its overall shape is cylindrical, but they are also segmented and have rows of sharp-looking spines on the upper edges of each segment, giving them a sturdy look.
The dog tail cactus is an epiphytic cactus. This means that in its natural habitat it lives on other trees and plants in a non-parasitic manner.
Note: We’ve written about a few other types of epiphytic cactus plants, such as the Christmas cactus, or even the Thanksgiving or Easter cactus.
On the other hand, the rat tail cactus has thinner stems that trail or cascade from the start. This makes it an excellent choice as a hanging plant.
Its stems are long and cylindrical, resembling rat’s tails after which it is named. It is covered with small, fuzzy-looking spines, giving it a softer appearance than the dog tail cactus.
At maturity, the stems can be 3-6 feet in length as a potted plant, although I’ve seen reports that they can get up to 6-9 feet in length. (I’m assuming that would be in the wild.) The stems can grow as much as 1 foot a year, but overall, rat tail cactus stems don’t grow as long as dog tail stems.
The rat tail cactus is an epiphytic plant just like the dog tail cactus.
If you are interested in growing one of these plants, You might want to check out this Dog tail cactus or this rat tail cactus on Amazon.
On a similar note, many people also have trouble telling the difference between a dog tail cactus and a dragon fruit cactus because they look almost identical at times. Look at this picture of my young dragon fruit cactus plant. At this stage of growth, you could easily mistake this plant for a dog tail cactus.
Appearance Comparison
- Dog Tail Cactus (Strophocactus testudo)
- Thicker and more robust.
- Grows upright initally before cascading down.
- Can reach up to 9-10 feet in length.
- Larger, sharp looking spines along the segment edges.
- Rat Tail Cactus (Aporocactus flagelliformis)
- Thinner cylindrical stems.
- Grows in a trailing or cascading manner from the start.
- Typically 3-6 feet long, potentially up to 9 feet in the wild.
- Small, fuzzy looking spines giving a softer appearance.
Flowers
Regarding flowers, the dog tail cactus typically blooms between March and July. It produces large, fragrant flowers that are white or pink. These flowers bloom at night.
In contrast, the rat tail cactus has smaller flowers that are red or pink, and they bloom during the day.
These flowers are more numerous compared to those of the dog tail cactus and they only last a couple of days.
Habitat
The habitats of these cacti also differ. The dog tail cactus is native to Central America and the Caribbean and prefers a slightly more humid environment.
The rat tail cactus, however, is native to Mexico and South America and thrives in drier climates.
Watering
Due to the differences in their native habitat, their care is slightly different.
The dog tail cactus requires more water than the rat tail cactus since it comes from a more humid habitat.
The rat tail cactus comes from a more arid environment; it can tolerate a more infrequent watering schedule than the dog tail.
But for both of them, you typically need to water them once the soil is completely dry, This can be about every 2 to 3 weeks, or 4 to 6 weeks during the winter.
Using a moisture meter reader can help you determine if the soil is dry enough before watering since sometimes I find that the finger test is not always good enough. Amazon has some that you can use and they are not expensive. This one is popular.
Sunlight
Both of these plants need about 6 hours of bright sunlight or filtered sunlight. You don’t want them to be all day in scorching, direct sun (especially in the summer months!) They also won’t do well in dark rooms, or in parts of the house that don’t have full sun.
If you don’t have enough natural sunlight in your home, you may want to consider supplementing with an LED plant light such as this one from Amazon. I like these Halo style plant lights since they are attractive.
Overall Comparison of Dog Tail vs Rat Tail Cactus
| Rat Tail Cactus (Disocactus flagelliformis) | ||
| Length of Stems | 9-10 feet in length | 3-9 feet in length |
| Types of Spines | Larger spines on segment edges | Small, fine spines, fuzzy appearance |
| Overall Shape | Sturdy, thicker plant, initally grows upright, then trailing | Thin, cylindrical stems, trailing |
| Flower Shapes and Colors | Large, white or pink | Smaller, red or pink |
| Size of Flowers | Larger | Smaller |
| When the Flowers Bloom | Night (fragrant) | Day |
| Country of Origin | Central America, Caribbean | Mexico |
| Watering Schedules | Every 2-3 weeks Let soil dry out between waterings | Every 2-3 weeks or more Drought tolerant, let soil dry out between waterings |
This video by Brainy Gardener on Youtube talks about how to take care of a rat tail cactus and it gives you some more pictures of how they look when mature.