About the fishbone cactus

Description

When thinking of cacti, humidity-loving forest dwellers that live on trees aren’t the first thing that comes to mind for most people. And yet, that’s exactly what the fishbone cactus is!

Similar to other other jungle cacti in looks, this one is characterized by its flat, segmented foliage. The difference is that, as its name suggest the leaves on the fishbone (or zig-zag, ric-rac) cactus are strongly serrated. In a normal planter, the leaves hang downward, but they can also be made to climb up a piece of wood.

Natural habitat

This cactus is naturally found in Mexico, where it occurs in the states of Jalisco, Oaxaca, Guerrero, and possibly Nayarit and/or Michoacán. It prefers humid forested regions at relatively high elevations, usually between 3,600 and 5,900 feet.

In its montane forest habitat, the fishbone cactus doesn’t grow in the soil like most plants do. Instead, it’s an epiphyte, meaning it (non-parasitically) uses taller trees as supports as it climbs its way to the forest canopy. (Epiphytes are quite popular in the houseplant world; other favorites you might know include Hoyas and Tillandsias.)

So is this a Disocactus or an Epiphyllum?

If you’ve been collecting houseplants for a while, you likely know the fishbone cactus as Epiphyllum anguliger. What’s up with the whole Disocactus anguliger thing?!

Well, that’s plant naming for you: it’s ever-changing and quite frankly, a total mess at times.

What happened is that molecular research revealed in 2016 that a bunch of the members of this genus weren’t actually Epiphyllums after all, and that they fit better in the genus Disocactus. The fishbone cactus was one of them, hence its name change.

Types of fishbone cacti

Flowering houseplants like this one are normally irresistible to nurseries: they can be selectively bred and hybridized to produce all sorts of different flower colors and shapes, not to mention variations in foliage.

It seems that plenty of different fishbone cactus cultivars do indeed exist, but strangely enough, they don’t appear to be particularly popular outside of clubs dedicated to growing them. It’s not like with Epiphyllums, where it sometimes feels like you’re going to drown in funky-named plant variations: Disocactus anguliger is usually just sold as “fishbone cactus,” nothing more and nothing less.

I was able to identify a few types of fishbone cacti:

• Disocactus ‘Red Tips’: As the name suggests, this cultivar develops orangey-red tips if it’s exposed to enough light.
• Disocactus ‘Jalisco’ series: Produced by Rudolf Hessing, these hybrids have fine flowers in different colors. 
• Disocactus ‘El Tecolote’: Large, creamy white blooms. 

Caring for a fishbone cactus

Light and temperature

Unlike desert cacti, fishbone cacti and other jungle cactus species don’t need tons of sun. They naturally grow under the forest canopy, meaning the harshest rays are filtered out. Don’t be fooled into thinking you can grow your Disocactus in a dark corner, though! 

The best indoor location for a jungle cactus is a window that receives bright indirect light. Some direct sun won’t be an issue, as it’s not nearly as bright through a window as it would be outdoors. If you grow your cactus outside during the summer, it does become more important to find it a sheltered spot to prevent it from burning.

In terms of temperature, this species isn’t too fussy, but it’s definitely not frost hardy. Temps between 59°F to 86°F are preferable for good growth. This being said, your fishbone cactus will benefit from cool temperatures (between 50°F to 55°F) during winter, as the chill encourages blooming.

For the best results, if need be, move your cactus to a cooler location in your home around December. Once buds start to form, usually around February or March, you can slowly acclimate it back to its normal, warmer position. With some luck, this will stimulate it to bloom off and on throughout the upcoming summer months!

Water and humidity

When caring for a jungle cactus, it’s important to keep in mind that they like quite a bit more water than desert cacti. However, because they’re naturally epiphytes, they definitely haven’t evolved to be stuck in constantly wet soil either. It’s all about balance.

I can’t say exactly how often to water your Disocactus, as this depends on factors like the amount of light it receives and the type of soil mixture it’s in. You’ll have to gauge the moisture level yourself in order to figure out when your cactus needs a drink.

• During the late spring to early autumn growing season, water a fishbone cactus whenever the first 2 to 3 inches of the soil have gone dry. This will usually be around once a week or so, but it may be sooner in warrm climates.
• During winter, when the plant is likely not actively growing, wait until the soil has gone at least halfway dry. This will usually be around once every two weeks, but it may take even longer.

If the leaves on your fishbone cactus are looking dry, wrinkly, and crispy, especially at the tips, your plant may need more water or is unable to take up water properly as a result of some kind of root damage. 

If the leaves are soft and discolored, you’re overdoing it and it’s succumbing to rot. You may have to use the methods described in the section on propagating a fishbone cactus in order to save what you can.

As for humidity, the forests this species naturally inhabits tend to be quite moist. In the home, it’s not hugely fussy, but it can suffer if the air is very dry. You could consider running a humidifier if the relative humidity level regularly drops below 40 percent in your home. 

Soil and planting

As you’ve probably concluded at this point, jungle cacti and desert cacti are quite different. They do have one thing in common, though: a preference for light and gritty soil. Desert cacti need airy soil because it promotes drainage; jungle cacti need it because as epiphytes, they don’t respond well to their roots being choked in a dense mixture. 

It’s easy enough to create your own soil mix that can be used for all sorts of cacti and succulents, including the fishbone cactus. There are lots of different ingredients and amendments you can use, but something basic would look a little like this:

• 2 parts houseplant potting soil
• 1 part perlite or pumice
• 1 part fine orchid bark

Your fishbone cactus will likely also appreciate the addition of a handful of compost or worm castings.

Fertilizing

Fishbone cacti don’t need a lot of fertilizer, but like almost all houseplants, they do appreciate some extra nutrients at long as they’re given at the right time. You can use a water-soluble, diluted houseplant food or cactus fertilizer once a month or so during the growing season. 

Stop fertilizing during the inactive winter months, with the exception of once during early spring. Right before you move the plant back to its normal location, you can give it some plant food to encourage blooming. A diluted orchid fertilizer should work well here.

Pruning

Unless you just want to remove some dead foliage, there’s no need to prune your fishbone cactus. Let it grow big and wild!

Dividing or repotting

The fishbone cactus is a good candidate for division, which is a helpful method if yours is outgrowing its planter but you don’t want to move it to a larger pot. Just take the cactus out of its container, shake the soil off the roots, and divide it into as many clumps as you want (slice vertically through the root ball with a clean knife if need be).

Once you’ve divided your Disocactus, you can place each clump in a planter with some fresh soil. Since the plants already have roots, they should keep growing as usual.