Orchids on Trees – Botanical Garden Proposal

Epiphytic orchids, many of which can be grown outdoors year around here in Southern California, are an essential part of jungle and forest ecosystems. Local botanical gardens can play a very important role in increasing public awareness, understanding and appreciation of these diverse and adaptable plants whose future hangs in the balance.

Goals and Objectives

Advance knowledge of how epiphytes contribute to biodiversity
Advocate the importance of habitat conservation
Explore ex-situ conservation possibilities
Expand the diversity of the plant collection
Add to the realism of the jungle section
Dispel the popular notion that all orchids require greenhouses
Demonstrate the horticultural value of epiphytes
Share lists of orchid species suitable for outdoor culture
Foster curiosity and interest in epiphytes
Promote the enjoyment of epiphytes
Direct public interest to associated organizations
Develop a synergistic relationship with local orchid societies

Cost

Very little (if any) monetary cost will be required of the garden. Drip systems cost around $25 per tree which I’ll be more than happy to help pay for and install. Orchids can be donated by local orchid societies, orchid nurseries and other botanical gardens. Members of local orchid societies can help mount the orchids to the tree(s). Some planning and coordination time will be required of the garden staff, but no more than for the average new installation or exhibit.

Precedent

That I am aware of, only 3 public gardens / zoos in Southern California have orchids on their trees…the Quail Botanical Gardens, the San Diego Zoo and the Santa Barbara Zoo. The relatively small number of gardens does not reflect the difficulty of growing orchids on trees, but instead reflects the widespread misperception of the difficulty of growing orchids…and emphasizes the importance of more botanical gardens taking an active role in helping to correct this widespread misperception.

Recommended Orchids

Hybrid orchids would provide horticultural value but from the perspective of education and ex-situ conservation, species orchids are preferable. The following is a short list of some of the more readily available species that are suitable for outdoor culture here in Southern California.

Ansellia africana (Africa)
Brassavola cucullata (Mexico)
Cattleya intermedia (Brazil)
Cattleya loddigesii (Brazil)
Dendrobium falcorostrum (Australia)
Dendrobium gracilicaule (Australia)
Dendrobium hercoglossum (Asia)
Dendrobium kingianum (Australia)
Dendrobium linguiforme (Australia)
Dendrobium nobile (Asia)
Dendrobium speciosum (Australia)
Dendrobium teretifolium (Australia)
Encyclia citrina (Mexico)
Encyclia mariae (Mexico)
Encyclia tampensis (US)
Epidendrum parkinsonianum (Mexico)
Laelia albida (Mexico)
Laelia anceps (Mexico)
Laelia autumnalis (Mexico)
Laelia gouldiana (Mexico)
Laelia purpurata (Brazil)
Laelia speciosa (Mexico)
Laelia superbiens (Mexico)
Miltonia flavescens (Brazil)
Myrmecophila tibicinis (Mexico)
Oncidium flexuosum (Brazil)
Oncidium maculatum (Mexico)
Rhyncholaelia digbyana (Mexico)
Stanhopea tigrina (Mexico)
Vanda coerulea (Asia)

Orchid Sources

The following is a list of potential sources for the recommended orchids. The incentive to donate orchids can be broken down as follows…botanical institutions benefit because not all of their eggs are in one basket, orchid societies benefit by helping to encourage interest in orchid growing and orchid nurseries benefit from being mentioned in the signage which functions as advertising.

Botanical Institutions

Local Orchid Societies
Orchid Nurseries

Requirements

Once the recommended orchids have been mounted to trees, they will require little more attention than a typical subtropical plant. Any additional maintenance can be provided by volunteers from the local orchid societies.

Temperature

The recommended orchids are eurythermal (temperature tolerant) and have been grown outdoors for many years by orchid hobbyists throughout Southern California.

Water

According to data from the Orchid Culture website, the average amount of rain per year received by the recommended orchids is 41 inches…which is half the amount of water that the typical Southern California lawn receives per year. These orchids should have little difficulty adjusting to the watering frequency and duration of the tropical garden section. My guess is that the tropical section is watered in the morning…perhaps more frequently during summer and less frequently during winter.

Epiphytic orchids generally prefer more water when they are growing (spring, summer) and less water when they are resting (fall, winter). Newly mounted orchids benefit from being watered more frequently because their root systems are not yet established.

The watering system that I set up in my tree is not automated. I run it for 20 minutes every evening during the hottest days and 10 minutes early morning once a week during the coldest days. In their native habitat, epiphytic orchids receive significantly less rain during winter...which is when they are resting. However, my mounted orchids do not seem to be bothered by our winter rains. In fact, they seem to perk up after the rain, most likely because the quality of the rain water is higher than that of the tap water.

Watering system

Drip systems can malfunction for various reasons and should be inspected on a regular basis (especially during summer) to ensure that they are providing adequate water for the orchids.

Fertilizer

Personally, I do not fertilize my orchids and they grow and flower just fine. Any fertilizing should be done when the orchids are actively growing and along the “weekly weakly” guidelines.

Pest control

Orchids are susceptible to damage from the usual suspects… mealy bugs, aphids, scale, slugs, snails, squirrels and rats. Squirrels and rats can cause the most damage in the shortest amount of time. The methods that the garden uses to control these pests should sufficiently protect the orchids.

Methodology

Select a date to start the project. Spring, when the weather starts warming up, is the best time to mount orchids on trees because that is when the orchids usually start developing new roots.
Determine suitable tree (phorophyte).
1. Origin: Ideally, in terms of realism, orchids should be mounted on the same trees that they would grow on in their native habitat. However, matching orchids to trees that have overlapping distribution ranges should be fine.
2. Form: The best branches are fairly thick, horizontal and within easy viewing distance but just out of reach. Vertical branches have one advantage in that fewer drip nozzles can provide water for all the orchids mounted beneath the drip nozzles.
3. Shade: The tree should provide sufficient light for the orchids that are mounted on it. If the tree is deciduous in winter, then that should factor into the decision.
4. Texture: Rough and deeply furrowed bark retains moisture longer than smooth bark.
5. Water tolerance: The water requirements of the tree and selected orchids should be closely matched...which is usually the case if there is overlap in distribution ranges.
6. Location: Frost tends to roll off hills and settle in valleys. Not sure how big a hill needs to be, but trees on hill tops might have more cold protection than hills in valleys. Trees near water are good choices as the orchids will benefit from the higher humidity in the immediate vicinity.
Select best location for the orchids.
1. Low on the tree: Climbing orchids, orchids with tall spikes.
2. High on the tree: Pendant orchids, orchids with large flowers.
3. Vertical branches: Orchids with lower water requirements, climbing orchids
4. Horizontal branches: Orchids with higher water requirements, running orchids
5. Forks: Orchids with higher water requirements
6. Main forks: Orchids that grow into large specimens
7. Sunny side: Orchids with higher light requirements
8. Shady side: Orchids with lower light requirements
Install a drip system.
1. Brown ¼” poly tubing is a good choice in that it is small and blends in well with most trees. Fishing line can be used to secure ¼” poly tubing to the tree.
2. Use T-connectors to run ¼” poly tubing up each main branch.
3. Select nozzles…ie drip, micro sprayers, misters, etc.
4. Attach nozzles to ¼” poly tubing
If practical, a copper strip can be wrapped around the base of the tree to deter slugs and snails
Attach orchids to the tree
1. Monofilament line is most hobbyists’ preferred method because it is not very noticeable.
2. Moss can be placed between the tree and orchid to provide additional moisture for the orchid. The quantity of moss used is determined by the watering frequency/duration and the moisture requirements of the orchid.
  1. Sphagnum moss: most moisture, least aeration
  2. Green moss: medium moisture, medium aeration
  3. Live Spanish moss (Tillandsia usneoides): least moisture, most aeration
3. A slip knot at one end of the fishing line can be used to maintain tension while attaching the orchid. The orchid must be firmly attached to the tree or else new roots will be damaged if the orchid is disturbed.
Remove monofilament line once the orchid has sufficient roots to support its weight.

Education

Signs should be placed in front of the trees with orchids. The signs should have clear, water proof, plastic containers where educational and informative fliers and articles can be placed for visitors.

Quail Botanical Garden Epiphyte Sign

Epiphytes
Plants that Perch

Orchids, ferns and other plants that grow on trees are called epiphytes (pronounced epp-ih-FIGHTS). Epiphytes use trees as a perch to grow on. They are not parasites and do not steal nutrients from the tree. They get water from rainfall and nutrients from leaf litter, dead insects, and animal droppings.

Treasures
In rain forests, thousands of epiphytes can grow on a single tree, providing shelter and food for many different kinds of animals. Conserving natural habitats protects orchids and other epiphytes.

El Cielo Reserve Sign

The Need for Conservation

Mexico is home to over 1,200 different species of orchids, making it one of the world’s greatest hotspots for these amazing plants.

But sadly, Mexico is ranked high in another category as well – it is 4th in the world for forest loss. Each year, Mexico cuts down approximately 4% of all its remaining woodlands, about 1,000,000 hectacres a year!

Since 60% of Mexico’s orchid species make their homes in cloud forests, it is no surprise that at least 22 species of orchids have disappeared from the wild since 1998.

There is another big problem as well – plant poaching, or the harvesting of orchids from the wild. In 2001, Mexico passed a national law, NOM-059-ECOL-2001, that makes it illegal for anyone to remove many orchid species, or even their flowers, from the wild.

What you can do to help:

First, remember that even plucking flowers from a single plant can be bad for the long-term health of an orchid – when you pluck its flowers you prevent it from make seeds and reproduce.

Take a picture, not a plant. Leave them be so that others can get a chance to share beauty. It is a fact that most plants do not survive being removed from the wild.

Buy your orchids from reputable orchid sellers with proper permits – market vendors often take plants, even endangered ones, from the wild and this leads to plant extinction.

Join an orchid society and learn all you can about these amazing plants – try the Mexican Association of Orchids online at http://amo.com.mx

Donate money to organizations that protect Mexico’s forests.

Funding Provided by Orchid Conservation International
www.orchidconservation.org

San Diego Zoo Epiphyte Sign

LIFE AT THE TOP

Look out into the tree tops. Fern Canyon’s diverse canopy simulates the tropical rain forest. Here dwell the winners of the fight for light and nutrients in a complex ecosystem. At the top, direct rainfall and sunlight nourish the trees and the orchids, bromeliads, and staghorn ferns that cling to them. Beneath these penthouse inhabitants are the tree ferns, bananas, and smaller trees that must subsist on what filters past the forest giants.

At ground level, we can see through the deep shade to the stems of the philodendrons that climb the trees to reach the sunlight. Here, too, are the spiky aspidistra, lacy ferns, broad-leaved ginger and taro of the forest floor.

HOW DO THEY SURVIVE?

Rain runs down cracks in the bark of trees to the ground, carrying bird droppings and dust that nourish the air dwellers whose roots cling to the bark. On the ground, leaves and vegetation that fall from the canopy decay quickly, feeding the roots of all the rain forest residents.

HOW MANY CAN YOU FIND?

Orchids, bromeliads, and staghorn ferns perch in the forks of trees, on living and fallen branches, and on tree trunks. Study the canopy. How many can you find?

WHEN A TREE FALLS…
Rain forest. Nowhere else are there so many plants and animals. We know the names of half a million of its leafy citizens, but those compose only a small fraction of more than 3 million different plants that call the rain forest home.

People call the rain forest home, too. It has served them for thousands of years, as their grocery, their pharmacy, and their hardware store. Today the demands of the industrial world have pushed both endemic people and the rain forest to the edge of extinction.

In a largely industrialized world, 40% of tropical people live in poverty. Slash and burn agriculture feeds the people but destroys the rain forest. A farmer with an axe can clear almost 2.5 acres of forest in 12 days. After a few years of farming the thin, fragile layer of fertile soil is exhausted and the farmer moves on.

Once cut, the rain forest may never return. What remains? Dense scrubby vegetation-jungle, succeeds initial clearing.

RAIN FOREST WATCH
At current rates of destruction, the rain forest shrinks:
1 minute – 54 acres
15 minutes – 1 to 2 square miles
24 hours – an area the size of the city of Philadelphia
One year – an area the size of Great Britain
36-50 years – virtually eliminated

EXHIBIT SPONSORED BY THE SAN DIEGO ORCHID SOCIETY

San Diego Zoo Guided Tour Maps

Once the orchids have been mounted in a tree...a photo of the tree can be taken and used to draw a map of the epiphytes on the tree. This will help people identify the orchids mounted on the tree(s).

Additional Resources

Roberta's Orchid Central - Varied collection of orchids grown outdoors in Southern California.

Photos

Landscaping with Orchids group on flickr.

www.flickr.com