Growing orchids directly on trees mimics the natural environment of these plants, providing an aesthetically pleasing and biologically sound method of cultivation. Orchids grown in this manner are epiphytes, meaning they naturally grow upon other plants for physical support without extracting nutrients from their host tree. Their specialized aerial roots, covered in a spongy layer called velamen, are adapted to rapidly absorb moisture and nutrients directly from the air and rain. Successfully transitioning an orchid from a pot to a tree involves careful selection of both the plant and the host, followed by precise attachment and ongoing care that accounts for this unique exposure.
Selecting the Right Orchids and Host Trees
Success begins with choosing naturally epiphytic orchid species, which are suited for life without soil. Popular and adaptable choices include Vandas, Cattleya hybrids, and Phalaenopsis, all of which possess the necessary aerial roots and tolerance for quick-drying conditions. Avoid terrestrial orchids, which are adapted to grow in the ground and will not thrive when mounted on bark.
The host tree itself serves as the anchor and provides the necessary microclimate. Trees with rough, corky bark, such as oaks, citrus, or certain palms, are ideal because their textured surfaces offer crevices for the orchid’s new roots to easily latch onto. Conversely, trees that shed bark rapidly, like eucalyptus, or those that exude toxic resins, such as pines, should be avoided as they prevent secure root attachment and can harm the plant. The tree’s canopy must also permit adequate light filtration, as most epiphytic orchids require bright, indirect light, with sun-loving species like Vanda tolerating more direct exposure than shade-preferring Phalaenopsis.
Step-by-Step Mounting Techniques
Preparing the orchid for mounting requires gently removing it from its pot and carefully shaking away all existing potting medium from the root mass. The roots should be soaked in water for about 20 minutes to increase their flexibility, which helps prevent breakage during the attachment process. Any dead or damaged roots should be sterilized and pruned using clean shears to promote healthy new growth.
The orchid should be positioned on the tree so that its base—where the stem meets the roots—is in firm contact with the bark, usually on a horizontal branch or the main trunk where water naturally trickles down. A small, thin pad of moistened sphagnum moss can be placed around the root base, not packed tightly, to help retain initial moisture and humidity without smothering the roots. The roots must remain exposed to the air for proper gas exchange and eventual attachment to the tree.
The attachment itself must be firm to prevent movement, which can inhibit the delicate new root tips from adhering to the bark. Non-toxic, biodegradable materials like natural jute twine, cotton string, or strips of nylon stocking are used to secure the plant. The tie should pass over the root ball and around the tree or branch, ensuring it does not cut into the pseudobulbs or new growths. The binding material will eventually degrade, by which time the orchid’s own aerial roots should have firmly anchored the plant to the host tree.
Essential Post-Mounting Care
Once the orchid is mounted, the care regimen must change to account for the increased air exposure. Mounted orchids dry out much faster than their potted counterparts because the root system is fully exposed without the moisture retention of potting media. They will require more frequent watering, often daily in warm or dry weather, typically applied as a heavy mist or drenching to fully saturate the roots in the morning.
Good air circulation is necessary to dry the roots quickly after watering, which prevents fungal and bacterial issues that thrive in stagnant, damp conditions. The orchid must also receive bright, filtered light; insufficient light will prevent blooming, while harsh, direct afternoon sun can scorch the leaves.
Nutrient delivery is also different for mounted orchids, which naturally derive trace minerals from debris and rainwater. They require less fertilizer than potted plants, but a highly diluted, balanced liquid orchid fertilizer (quarter-strength) should be applied weekly or bi-weekly. This fertilizer is most effectively delivered as a foliar spray or liquid feed directed at the roots, supporting vigorous new growth and permanent establishment on the host tree.