Dog Tail Cactus

Dog tail cacti are popular house plants among succulent and cacti enthusiasts. They are very easy to care for when grown in the right conditions and, like most succulents, their propagation is a breeze. Additionally, their unique growth habit and place of origin make them all the more interesting.

In this article, we’ll talk about where this unique cactus species originates and find out what sets it apart from other cacti. After, we’ll talk about what it takes to keep a dog tail cactus healthy and even how to propagate one so you can expand your succulent collection!

What Is a Dog Tail Cactus?

The dog tail cactus (Deamia testudo) is a forest-dwelling cactus that is native to the forests of southern Mexico, Belize, Costa Rica, Guatemala, Honduras, and Nicaragua. The accepted botanical name is synonymous with several not-accepted or antiquated names — Cereus miravallensis, Cereus testudo, Deamia diabolica, Selenecerus testudo, Selenecereus miravallensis, and Strophocactus testudo are sometimes used interchangeably to refer to this species.

This species is quite different from the desert cacti that most people are familiar with. Not only does it grow in shaded, humid forests, but it is also an epiphyte rather than a geophyte. This means that, like many orchids, it grows outside of the soil, anchoring instead to the surfaces of plants or other porous, stationary objects. Most commonly, the dog tail cactus trails throughout the canopies of trees, where it wraps itself tightly around branches or hangs down towards the forest floor. There, it can collect plenty of sunlight and pass moisture.

Without contact with the soil, the dog tail cactus does not have access to the wealth of nutrients and moisture that most plants do. Instead, it must collect passing moisture in whatever ways it can. To stay hydrated, it relies on rain events, atmospheric moisture like fog and mist, and the comparatively little moisture held by the surface it is growing on. As this water passes over the plant’s roots, it carries with it any nutrients leached from other surfaces and decaying organic matter it has passed over, such as leaves, bark, animal droppings, and dead insects. As its roots absorb the water, the cactus also scavenges the nutrients it needs to survive.

Caring for a Dog Tail Cactus

While it is different from desert cacti in terms of its care requirements, the dog tail cactus is still easy to care for. With good attention to its basic growing conditions and the frequency with which you water, your dog tail cactus will live happily for many years.

Below, we’ll outline the conditions that your dog tail cactus will need to thrive, as well as how to propagate it once it has grown large enough.

Sunlight

The dog tail cactus, being a forest-dweller, requires partial sun and dappled shade throughout the day. If you are growing your cactus indoors, you will want to place its container near a window that receives bright but indirect sunlight over the day.

If your cactus has been growing indoors or has spent the winter indoors, you may want to move it outside for the spring and summer months. In this case, you’ll want to acclimate it to the outdoors gradually, as you would when hardening off any other plant. Begin by placing it in a fully shaded location and gradually increase the length of time it spends there by an hour or two per day. Once it has become used to this location, gradually acclimate it to what will become its full-time, partially shaded location. Ideally, it will receive most of its sunlight during the morning and evening hours, with dappled shade during the heat of the afternoon.

Water

As a forest dweller, the dog tail cactus requires a lot more water than desert cacti. To ensure that your cactus stays healthy, you will need to water it regularly, especially if you are keeping it outdoors during the summer months. Because it is an epiphyte, you will also need to take care to avoid overwatering. If you begin to notice yellowing, limp, or drooping stems, you are likely giving your plant too much water and should cut back.

Growing well above ground level as it does in the wild, the dog tail cactus is not likely to encounter standing water. In cultivation, however, where it is often grown in a pot, root rot is significantly more common. Always check the status of your plant’s potting medium before watering rather than watering at a consistent interval. If the medium hasn’t dried out completely, do not water your plant. Only once it has dried should you give your cactus more water.

Soil Conditions

The dog tail cactus can grow quite large — around 9 or 10 feet in length in its native range. In cultivation, however, especially if its space is limited, it will usually remain smaller. Its climbing and trailing nature can create a beautiful cascading effect when it is grown from hanging baskets or porch planters. If you choose to go this route, be certain that whatever container you choose has drainage holes at the bottom.

Plant your dog tail cactus in a pot of well-draining potting substrate designed for orchids or cacti. In a pinch, a standard, soil-less potting mix will work as well. However, you should ideally amend it for additional drainage. Add quite a bit of perlite, pumice, or other horticultural grit to increase the pore size of the potting mix. This ensures that water moves quickly through the substrate and that your plant’s roots can stay well-oxygenated.

If you live in an area that doesn’t experience long periods of weather below 40 degrees Fahrenheit, you can plant your cactus outdoors where it can grow as a true epiphyte. This species is a good addition to partially shaded rock gardens or for planting along hardscaping, where it will attach to objects with its adventitious roots. It will also climb nearby trees in the landscape. If you choose to plant your cactus outdoors, make sure that water never builds up at the planting site.

How to Propagate a Dog Tail Cactus

Dog tail cacti are easiest to propagate by taking cuttings. To do this, carefully cut off a piece of the parent cactus using a sanitized knife. Dull cutting tools can be dangerous to both the user and the plant at hand, so be sure that your knife is very sharp. You may also choose to wear thick gloves to protect your hands from the sharp spines. Handle the plant with care, making as clean a cut as possible through one of the joints in between two stem segments. Ideally, your cutting should be several inches long and encompass the entire segment. If this isn’t possible, make a clean cut in between a row of spines.

Once you have taken your cutting, set it aside in a cool, dry area of your house. Over the next few days, the wound at the base of the cutting will dry out and scab over, protecting the internal tissue of the plant from infection.

Some gardeners choose to dip the cut end of the plant into rooting hormone to encourage new roots to form. However, this is not strictly necessary. After it has healed over, you can plant your cutting a few inches deep, directly into a pot of moistened, well-draining potting mix. Mist or water your new dog tail cactus lightly for the first couple of weeks as it develops its first roots. After about a month, you can treat your cactus the same way you would the parent plant.