An Orchid on Every Tree
Epiphyte Grand Prix
Plant selection...the more frequently you're willing to water, the greater the variety of plants that you can grow on your tree. The less frequently you water, the more storage/succulence a plant must have to thrive on your tree. Lately I've taken to fondling leaves to gauge stiffness/succulence. How quickly a plant wilts is also a pretty good indicator of how it might do on a tree. But don't be afraid to experiment!
Epiphytes are naturally a good choice to start with but they range from plants with absolutely no storage capacity to plants that can go weeks without water. Some examples of drought tolerant epiphytes include CAM orchids and many atmospheric Tillandsias. Cliff dwellers and terrestrial succulents are also great candidates.
CAM orchids. The orchid family has more species of "succulents" than any other family. In fact, many orchids even grow on succulents/cactus. CAM orchids require excellent drainage and quite a bit of summer heat. I'm growing many of them in full direct sun where I live (around 15 miles straight line distance from the coast). The closer you are to the coast...the more direct sun you'll have to give them in order for them to complete their growth cycle before winter. Here are some examples of CAM orchids and/or orchids which should be treated accordingly...
- Ansellia africana
- Barkeria (all)
- Brassavola (all)
- Cattleya maxima
- Cattleya nobilior
- Cattleya walkeriana
- Dendrobium canaliculatum
- Dendrobium compactum
- Dendrobium speciosum
- Dockrillia linguiforme
- Dockrillia teretifolium
- Dockrillia wassellii
- Encyclia (all)
- Laelia (Mexican... albida, anceps, autumnalis, furfuracea, gouldiana, speciosa)
- Laelia sincorana
- Myrmecophila (all)
- Mystacidium capense
- Oncidium cebolleta
- Oncidium onustum
- Psychilis krugii
- Rhyncholaelia digbyana
- Rhyncholaelia glauca
- Schomburgkia splendida v cauca
- Schomburgkia superbiens
- Sobennikoffia robusta
Hanging Plants...some of my favorite plants for trees are those that are pendent/hanging/cascading. Here's a very partial listing...
- Asclepiadoideae - Ceropegia ampliata/distincta/sandesonii/woodii, Dischidia bengalensis/formosana, Hoya micrantha?
- Begonia boliviensis
- Bromeliads - Neoregelia hoehneana, Tillandsia intermedia
- Commelinaceae - Callisia fragrans/tehuantepecana, Tradescantia pendula/sillamontana
- Ericaceae - Agapetes serpens, Macleania insignis
- Ferns - Microgramma vacciniifolia, Polypodium subauriculatum
- Fuchsias - Which are the best pendent species?
- Gesneriads - Aeschynanthus speciosus, Codonanthe devosiana/carnosa/gracilis
- Impatiens keilii
- Medinilla sedifolia - one of the best, but perhaps only suitable for tropical climates
- Orchids - Dockrillia teretifolia (my favorite orchid) /pugioniforme/bowmanii/striolata, Epidendrum parkinsonianum, Schoenorchis juncifolia
- Pelargonium peltatum
- Peperomias - Peperomia kimnachii/prostrata/urocarpa
- Plectranthus prostratus/spicatus
- Succulents - Aloe arenicola/cremnophila/hardyi, Aptenia cordifolia variegata, Crassula marginalis/pellucida/sarmentosa variegata, Delosperma cooperi, Echeveria rosea, Graptopetalum, Kalanchoe manginii/uniflora, Lampranthus, Portulacaria afra variegata, Rhipsalis, Sarcostemma sp, Sedum craigii/lineare 'Variegatum'/morganianum/nussbaumerianum/sieboldii variegatum, Senecio jacobsenii/radicans/rowleyanus variegated
Drip System...if a tree is small enough then it's easy enough to water the plants by hand. My tree is quite large so I ran a drip system up it. My hose attaches to 1/2" polytubing which runs to the base of the tree. From there I have 1/4" brown polytubing which runs up the tree. At major forks I used 1/4" barbed T's to run the polytubing up both branches...
At strategic locations on the tree I placed 1 GPH drip emitter...
Watering Frequency/Duration...depends on the temperature. During the very hottest days I'll try and water my tree every other night for around 20 minutes. Because of the lower evaporation rate, watering at night allows the plants as much time as they need to fully hydrate. By noon most of the plants on my tree are completely bone dry. During winter I water first thing in the morning two or three times a month.
CAM orchids and most Tillandsias also need more water when it's warmer... but they can thrive with less frequent watering.
Tree suitability...generally the more texture the bark has the better. In terms of water...it should be pretty straightforward that you'll want to attach plants to trees that have similar water requirements. Canopy density is also another factor to consider as is whether a tree is deciduous. Plenty of plants that require shade during summer have no problem with direct sun during winter. But a deciduous tree will not offer as much frost protection during winter. Pygmy Date Palms are excellent phorophytes because their fiber provides an excellent medium.
For people with limited space...bonsai trees are perfect for numerous small epiphytes...
When to attach...the best time to attach a plant is when it just starts to initiate growth. I've made the mistake of attaching plants like Hoyas and Dischidias way too early in the year. Without enough heat to initiate root growth they just slowly dehydrated. What I recommend doing is first establishing trickier plants on 10" sections of thin wood...like the kind used for cheap trellis. First I cover the wood with a layer of moss and then I use fishing line to secure the plant and the moss to the wood. Afterwards I place the mounts in a terrarium (or clear plastic storage bins wrapped in clear plastic bags) in my garage under lights or in a bright window. Once the plants are well rooted to the wood then I'll attach the entire mount to the tree when it's warm enough. To ensure sufficient contact with the tree bark I'll add moss or a section of coconut fiber to the back of the wooden mount.
Medium...here in Southern California, because of our winter rain climate, it's safer to attach CAM orchids to trees without any moss. Initially I mounted Cattleyas with moss but many of them rotted during winter. So now I don't include any moss when I mount CAM orchids.
As far as I can tell...all plants, except for the CAM orchids and epiphytic bromeliads/Tillandsias, will require some additional medium. At first I tried attaching succulents to my tree without any medium. Some quickly put out roots while others did nothing. They received enough water to stay alive but the texture of the bark alone was not sufficient to encourage growth. Now I include some moss and the succulents have really responded.
There are different mediums that you can experiment with. New Zealand Sphagnum holds the most moisture and lasts the longest. This is the moss I use for more moisture loving epiphytes (Ericaceae, ferns, etc). It's not cheap so I use the less expensive green moss for succulents and other similar plants. The green moss doesn't retain as much moisture and breaks down relatively fast. Once it breaks down though it becomes a suitable substrate for the common live moss that we find around our gardens. I'd really love to learn which species of moss will grow the best on trees here in Southern California.
Lately I've been experimenting with the coconut fiber that they use for basket liners. On its own it doesn't seem to hold enough moisture for succulents. But if you add a thin layer of moss on top of the fiber then the succulents will really take off. I got the idea for the coconut fiber from observing how well all the plants did that I attached to my pygmy date palms. They really love the fiber...it seems to hold just the right amount of moisture. There are quite a few other fibrous palms...such as Trachycarpus fortunei. I'm sure fiber density varies by palm species so you'll have to experiment to see which plants respond the best to which palms.
Where to attach...horizontal branches are the best for hanging/cascading/pendent plants...plus they can retain more moisture than vertical branches. Vertical branches are the easiest to water by drip system. Locations higher up in the tree are good for plants that have larger flowers and prefer more dryness/light/air movement. Locations lower down on the tree are good for fragrant species, miniatures and plants that prefer shade/moisture. The sunny side of the tree is good for plants that require more light and can handle drying out more. Forks are ideal spots for moisture lovers but they are also ideal places to step if you're going to climb your tree (in no way shape or form do I recommend climbing your tree). Make sure you don't attach orchids where your ladder leans up against the tree. That sounds obvious...but I've managed to do it a few times.
Attaching plants...I attach plants to the tree using fishing line. The strength of the fishing line I use varies from 10 lbs to around 30 lbs...depending on how heavy a plant is. For orchids it's extremely important that they are as tightly secured to the tree as possible. Even the slightest wiggle room can damage newly emerging root tips...which will really set the orchid back. To make sure the orchids are fastened as securely as possible I use a slip knot method which allows me to cinch the fishing line tight without losing tension. After cinching the line as tightly as I can without cutting into the orchid...I loop it around several times and then create another slip knot (on the leftover line) to tie the line off without losing tension.
Planting pockets...for plants that want a bit more moisture I've been creating super simple baskets/pots/pockets out of the coconut fiber I mentioned earlier. Basically I cut a rectangle shape, fold it in half, cup one half, punch a hole through both sides with a scissors and then tie both halves together using fishing line. Then I'll add some medium and place plants/cuttings/seeds in the pocket. It's easy enough to attach the pocket to the tree with fishing line. If you water your tree by drip then you'll want to secure the bottom of the pocket as tightly as possible to the tree so that water will flow onto the bark rather than just falling off the tree.
In the lower left side of this picture you can see some newly added pockets.
If you add some small trailing succulents to the pocket they will quickly cover it.
Pests...unlike hanging baskets...pests will have direct access to plants on your tree. I very highly recommend keeping the base and lower trunk of the tree as free of plants as possible. Here's a short time lapse video of a few of us helping a friend clear the base of his tree to get it ready for epiphytes. Keeping the base clear will reduce the "staging areas" that many pests ...slugs, snails, sow bugs, earwigs, millipedes...will need to make nightly forays up into your tree. Ants are adept at climbing trees and are only too happy to carry mealybugs and scale to your plants. If you keep the base of your tree clear then it's easy enough to sprinkle a perimeter of deterrent around the trunk.
Protection/Fertilizer...generally I don't bother with fertilizer but this last summer I noticed a few aphids on my Rhipsalis and on the flowers of my Dockrillia teretifolia. So I sprinkled some granules of Bayer Rose Protect and Feed on the forks of my tree. It immediately destroyed the aphids. In terms of feeding...many of the orchids that had been producing one new growth per season vigorously produced two new growths. Unfortunately, somehow way too many granules fell onto my Vriesea espinosae and it was burnt beyond repair. So if I use the granules in the future I'll probably attach some coconut fiber pockets to my tree specifically for the Bayer granules. Of course, you wouldn't want to use any systemic pesticides on fruit trees.
Conclusion...when we see a yard that's completely covered in lawn it's easy enough to imagine the possibilities for that space. But when you see a tree...can you imagine all the possibilities for that vertical space? Plants are all about the conquest of space...so if you're running out of horizontal space then I highly encourage you to think epiphytically.