Orchids that thrive on trees are known as epiphytes, or “air plants,” which grow non-parasitically on other plants for physical support. This practice replicates their natural growth environment, leading to healthier and more vigorous plants. In their native tropical and subtropical habitats, these orchids anchor themselves to tree trunks and branches, absorbing moisture and minerals from the air, rain, and accumulated organic debris. Mounting an orchid on a tree provides the excellent air circulation and quick drainage their specialized roots require, preventing root rot common in potted specimens. This technique allows the root system, covered in spongy velamen tissue, to function optimally by rapidly absorbing water and securing the plant to the host bark.
Selecting Compatible Orchids and Host Trees
Success in tree-mounting orchids begins with choosing epiphytic species and a suitable host tree. Orchids like Cattleya, Phalaenopsis, Dendrobium, and Vanda are excellent candidates because they are naturally tree-dwelling. Terrestrial orchids, such as Paphiopedilum or Cymbidium varieties, are unsuitable as their roots are not adapted to cling to bark or endure rapid drying.
The ideal host tree must have rough, textured bark for the orchid’s roots to grip and anchor securely. Suitable examples include oak, citrus, avocado, and cork trees, which offer a rugged, non-shedding surface. Avoid trees with smooth bark (like birch) or those that secrete toxic sap or resin (like pines and firs), which can harm delicate roots. Select a host tree that provides filtered light, which is preferred by most orchids, often found on the north or east side of the trunk or under a light canopy.
Preparing Materials and the Orchid Root System
Before beginning the attachment process, gather the necessary materials for securing the plant and retaining initial moisture. Supplies include natural, biodegradable twine or wire, such as jute, hemp, or coated floral wire, to temporarily hold the orchid in place. You will also need a small amount of moisture-retention material, like sphagnum moss or coconut fiber, which will act as a temporary humidity buffer for the roots.
The orchid requires careful preparation to ensure a successful transition to the tree. Gently remove the plant from its container and thoroughly clean the root ball of all old potting media, such as bark chips or soil, as these materials can hold excess moisture and promote rot. Use sterilized cutting tools to trim away any dead, mushy, or discolored roots; healthy roots should appear firm and white, green, or tan. Finally, soak the entire root system briefly in water to make the roots pliable and less prone to breakage during mounting.
Step-by-Step Technique for Secure Mounting
The physical attachment process requires careful placement and secure fastening to encourage the orchid’s roots to grow onto the bark. Identify the best location on the tree, ideally a spot with filtered light where rain naturally trickles down (often observed as a darker patch on the trunk or branch). Position the orchid so its roots are spread against the bark, with the growth point (rhizome) facing slightly upward to allow for natural vertical growth.
Next, place a small, thin pad of moistened sphagnum moss directly over the orchid’s roots, ensuring it is not overly thick or waterlogged. This moss layer provides initial humidity and moisture while the orchid acclimates to the open air. Use the chosen twine or wire to wrap firmly around the roots, moss, and tree trunk, securing the orchid tightly without crushing the rhizome or new growth. The orchid must not shift or wobble, as movement inhibits new roots from firmly attaching to the host tree.
Long-Term Care and Establishment Monitoring
Caring for a newly mounted orchid involves adjusting maintenance routines due to the increased air exposure of its root system. Mounted orchids dry out much faster than potted ones, often requiring watering almost daily, especially during dry or hot periods. Drench the entire plant and mount until thoroughly saturated, allowing the roots to absorb moisture rapidly before it evaporates.
Nutrients must be supplied regularly due to the frequent flushing of water, as the bark offers little sustained feeding. Apply a highly diluted liquid orchid fertilizer, often half-strength or less, during watering, typically once or twice a week during the growing season. This consistent, light feeding prevents the salt buildup that occurs when concentrated fertilizer dries rapidly on exposed roots.
Monitoring for successful establishment involves observing the growth of new, healthy roots, which appear as bright green or white tips extending from the older root mass. The mounting is successful once these new roots have visibly adhered and grown tightly into the bark surface, a process that typically takes six to twelve months. Once the orchid is securely anchored by its own roots, the temporary ties should be safely removed to prevent them from girdling the plant or the tree.