Many of the succulents you list are cremnophilous, not epiphytic. They grow on sheer cliffs. While the pendant habit and root structures may be similar to some epiphytes, the culture requirements are not.

The cremnophytes will anchor into a crack and utilize whatever small amount of soil there is. For the most part, they will not sit on top of debris like an epiphyte. There is often intense wind in these habitats so the roots can be extensive. Most will not thrive in the same conditions of humidity, organic debris and constant moisture, as an epiphyte would.

I also think they would look unnatural plastered to a piece of bark, but that is my personal taste.

Now if you wanted to grow succulents hydroponically - well, that's a different story...

x

Never heard the word "cremnophilous" before...thanks! Well...the moisture requirements of epiphytes can be represented by a bell curve. It's certainly reasonable to say that the large majority of epiphytes grow in humid/moist environments. For example, orchids such as Pleurothallids occur in moist cloud forests. These types of orchids have no storage organs. However, there's a strong correlation between moisture and competition. Cactus and other succulents avoided the competition for "prime" real estate by being able to grow in areas that were too dry for most other plants. Plenty of epiphytic orchids have done exactly the same thing by adapting to drier forests. In fact, what most people don't realize is that the Orchidaceae has more CAM species than any other family.

A while back, when I was deciding which orchids to try and grow outside year around here, I primarily selected orchids based on their elevation. But on a day by day basis, dryness is the biggest challenge to growing orchids epiphytically here. Rather than trying to water more I've just been selecting orchids that have no problem going completely bone dry between waterings.

In terms of moisture equivalence, I know there are plenty of succulents that would fit right in with my epiphytes...but I have no idea whether their roots would be able to adhere to the bark sufficiently to support their weight...or whether their roots would desiccate when exposed. Most of the Kalanchoes I'm trying have fairly sturdy aerial roots so I figured I'd experiment with them first.

Regarding aesthetics...yeah...I definitely don't see succulents on a stick being the next fad. But for me personally, it would look more natural than say a Tillandsia in a shell...

Rhipsalis - many varieties
Epiphyllum - TC/CC
Aporocactus
Hoyas are quite succulent and Epiphytic

There are lots of succulents that would work. I think most that form aerial roots would work. I am surprised no one else commented. I wish you the best of luck in this endeavor.

-David

Thanks David! You're really right about the aerial roots.

Here's an update on just a few of the succulents on my tree...

Last year I sowed a gazillion seeds from my largest Echeveria directly on the tree. To my surprise...perhaps only a few days later I started to notice a gazillion tiny seedlings sprouting up wherever there was a bit of moss. I had no idea that Echeverias were so easy to grow from seed. Here are a few pictures of the larger seedlings...

There are two or three large seedlings growing in the root basket of Dendrobium speciosum...

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Other succulents in that photo are Graptopetalums, Crassulas, Othonna capensis, Crassula streyi, etc.

Here's a large Echeveria seedling growing in the root basket of an Ansellia africana...

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This one is growing beneath a Begonia boliviensis...

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Another Echeveria on the tree is Echeveria nebularum...

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It's an epiphytic succulent from Mexico. Other succulents in the photo include... Crassula spathulata, Cissus tuberosa, Peperomia urocarpa, etc.

Here's a photo of the shady side of the same branch...

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Succulents in this photo include...Aeonium Kiwi, Graptopetalum, Peperomia graveolens, Kalanchoe NOID (purchased as K. manginii), a small Echeveria, Kalanchoe marnieriana, etc.

Here's a closer shot of the Peperomia...

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Peperomia graveolens and Crassula streyi both have nice reddish coloring on the underside of their leaves so in this regard they are well suited to growing epiphytically.

Here are a couple different Echeveria roseas that I added last year...

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Echeveria rosea grows epiphytically in Mexico. It's one of the most cold hardy Echeverias and is grown outside year around in parts of England. Not sure why it's not more commonly grown here in Southern California as it can color up nicely when in bloom.

During summer I water the tree every other night via drip system. During winter I water the tree first thing in the morning around 3-4 times per month. Many of the succulents seem to be able to survive indefinitely on just the plain bark of the tree...but they go into bonsai mode. In order to thrive they need some moss and/or detritus. I've also tried using coco fiber but it just doesn't retain enough moisture. What works pretty great is coco fiber with a layer of New Zealand Sphagnum on top.

Here are some other photos of succulents growing epiphytically...

Agave
Cactus
Cactus
Cactus
Cactus
Crassula multicava
Cyphostemma currorii
Dudleya
Echeveria alata
Echeveria dactylifera
Echeveria nebularum
Echeveria nodulosa, Aloes, Mamillaria
Echeveria nodulosa
Echeveria nuda
Echeveria rosea
Echeveria rosea
Echeveria rosea
Echeveria secunda
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Kalanchoe uniflora
Mamillaria
Mamillaria
Mamillaria
Opuntia
Opuntia
Opuntia
Yucca lacandonica and Agave

Epiphyte, I love your succulent tree. It's inspiring. Thanks for the beautiful photos and links.

E. rosea is such a stunning echeveria. I have never seen it in a nursery around here.