Care Diary: Epiphyllums, the Orchid Cactus

While the true species almost all have the white, pale pink, or cream colored flowers, they hybridize readily with cacti in the tribe Hylocereeae, particularly those in the genus Disocactus (not to be confused with Discocactus!). These cacti have more brilliantly colored blooms, ranging from deep reds and pinks to pale lavender and yellows. 

Most of the “epis”, as these are commonly called in shorthand, are hybrids rather than true species. Epiphyllums and the species they’re crossed with are found throughout Central and South America and the Caribbean, thriving in just about any climate where they can get the consistent moisture they need for their epiphytic lifestyle. 

Epiphytic means, roughly, “air plant” – a plant that grows on the surface of another plant and gets its moisture and nutrients from air, rainfall, or collected detritus accumulating around it. 

A woodpecker taking a drink next to my Epi hybrid “Frosty Lime”. 

Cultivation Requirements

While Orchid Cacti are typically epiphytes in their natural habitat, they do not need to be grown as epiphytes in cultivation. You have multiple options for growing yours, ranging from keeping them as hanging plants or potting them like any other cactus. I picked up my three hybrids as cuttings from the San Diego Safari Park’s collection, started them as hanging plants, and soon found them getting too big and unwieldy to stay in them.

Soil

You’ll need a well-draining soil to mimic the type of drainage these plants prefer as epiphytes. In my climate, with the extremely high summer temperatures and the challenges I faced in keeping them from drying out too much, I use 100% succulent soil mix rather than adding any pumice. You may need more pumice for drainage if you’re in a more humid climate or have regular rainfall that these will experience.

I’ve also tried mixing succulent soil with a tropical soil mix (thinking that since these are tropical/jungle cacti, they might appreciate the extra nutrients) and there was no real difference. 

The crucial part here is that the soil is well draining and dries out within a few days of being watered. They do not typically have great root systems, so over-potting them can very quickly backfire. My “Frosty Lime” pictured above is over-potted, but I mixed the soil in that pot with about 50% pumice to ensure there was enough drainage through the entire pot. By comparison, the two hybrids I have in terra cotta pots are in 100% succulent mix, as the terra cotta allows for water to evaporate from the soil more rapidly than in the fired ceramic display pot. 

Watering 

These are subtropical to tropical cacti, and as such need much more water than a typical cactus. In my case, that means I often need to water these daily or every other day during peak summer months, and once a week or every other week in winter. You can look at your cactus for clues as to how much water it does (or doesn’t) need.

Light and Temperature Preferences

While these are cacti, they do not need full sun the way a typical cactus would prefer. In fact, they do worse with high heat and high sunlight, taking longer to grow and establish than they would with at least partial shade and cooler temperatures.

For best growth, you’ll want to give yours plenty of light but not full sun – protection from the hottest and brightest part of the day (around noon to three pm, typically) is usually enough. If growing indoors, they should be in the absolute brightest window, and I recommend moving them outdoors once your region has nighttime temperatures above 40F.

The nighttime temperatures in the 40s and 50s is essential if you’d like to encourage your Epis to bloom! Mine have done well with brief nighttime dips into the high 20s and low 30s, as long as the only frost on them was a very thin and light layer than melted quickly. It’s not recommended to let them experience actual frost very often, or ever, but the colder temperatures and longer nights they experience in winter are essential for blooms the next year.

They do not like getting extremely hot without plenty of airflow, and I keep mine on my front and back patios rather than hanging in my greenhouse. The average daytime temperatures in my greenhouse, even on moderate days, seem to be too warm and they don’t thrive. 

Epiphyllum “Challenge”

Fertilizer

I’ve used dilute fish emulsion, tropical plant fertilizer, cactus fertilizer, and most recently, a balanced 20:20:20 fertilizer for watering my Epis. 

It doesn’t seem to matter much, but you should avoid over-feeding your epiphyllums. They naturally grow in an environment with minimal nutrients, so excess fertilizer can burn them or cause issues. A nice feed in early spring, when they first start waking up from winter, can be highly beneficial to encourage a good blooming season. 

I don’t feed mine at all if I’ve recently repotted them, as the nutrients in the fresh soil are plenty. If the plant has been potted for over a year, I’ll feed at half strength about once a month through the growing season, and stop when the days start getting short and cooler in September. 

Epiphyllum “Derby Star” 

Establishing Cuttings 

The easiest way to grow new epiphyllums and their hybrids is, far and away, to grow them via propagation. 

Using a clean set of shears, cut a paddle off at one of the growth points. It’ll be a clear nodule on the main body where a new arm extends – it’s that part you’ll want to cut at. Let the cut dry for at least a day, preferably a few days, to ensure there’s a solid “scab” over the cut part. 

Once the cut has dried, simply stick that end in some well-draining soil and wait. You can also theoretically just lay them flat on the soil, but I haven’t tried that personally, I’ve just seen the arms of my potted cacti start growing new roots near the ground.

Don’t water the soil, but do keep it from during into a dry powder or cake; you’ll need to lightly water the soil if it seems particularly dry. After the first month, I’d moisten the pots with my cuttings every couple weeks. 

It took a few months for my cuttings to solidly grab into their soil with roots; I originally placed them into too much sunlight and the cuttings burned. When I moved their pots to more shade, they began rooting rapidly, with my Frosty Lime being the first to start taking off. 

Cuttings seem to do best when taken in spring and early summer, and allowed the warm summer months to root. 

I acquired all my cuttings in 2019, and my Frosty Lime was the first to bloom in 2021. My Derby Star and Challenge both bloomed this year, in 2022, but they also were the slowest to establish and were not kept ideally to encourage blooms. 

Look for an Epiphyllum society near you! 

While I’m extremely busy with our home, my greenhouse, and being a member of the San Diego Cactus and Succulent Society, there’s also an active and engaged Epiphyllum Society here in San Diego. 

If you love the flowers and want to learn more, I highly recommend joining your local society! You’ll find more hybrids, better information, and a wealth of resources in terms of engaged members happy to share information.