Orchids - The Ultimate Exotics

Bring home these cultivated beauties for a taste of faraway climes

- By Carolyn Jones

Close Your eyes and think of orchids. To what distant places are you transported? To a hot jungle in southeast Asia, loud with the calls of brightly coloured birds? To afternoon tea in a splendid English glasshouse? To an ancient Chinese courtyard garden? To a sailing ship headed from South America to Europe?

These exotic images reflect the rich and tumultuous history of orchids in cultivation. While there are species of orchids all over the world, including here in British Columbia, it is the tropical orchids that inspire our fantasies. When world exploration exploded it the 18th century, hundreds of species were imported into Europe. Greenhouses originally designed for growing oranges were used for orchids, but the dry air resulted in losses by the thousands. Sir Joseph Hooker, when director of the Royal Botanic Gardens, Kew, in the late 1800s, described England at that time as "the grave of tropical orchids." Not only did it take decades for horticulturists to successfully cultivate these exotics, it was not until the turn of the century that orchids could reliably be grown from seed. The work of French botanists Noel Bernard demonstrated the importance of particular fungi in seed germination and paved the way to creating hybrid orchids.

To learn more about orchids for today's gardeners, I visited Carol Hsu at Oriental Orchids in Burnaby (www.oriental-orchids.com). Carol's father, Tony, started the business in 1997 when, looking forward to caring for his 25 orchid plants, he retired from the building trades. Somehow retirement took on a new meaning, and the Hsu family now runs a state-of-the-art greenhouse operation with about 50,000 pots, mostly of moth orchids (Phalaenopsis). While there, I peered into as many different flowers as were in bloom and pondered this puzzle: How can this plant family's 18,000 species be variable and recognizable at the same time? How can orchids be so diverse that we are endlessly fascinated with their form and yet so similar that almost anyone can spot one? A quick look at their anatomy reveals the answer.

This huge family of flowers shows little major floral or foliage diversity. Basically, species are variations on a theme - a very successful theme. As with many other animal-pollinated flowers, the showy flower parts are its sepals and petals. The three sepals are usually similar and enclose the flower bud during its formation, but it is the three petals that inspire our flights of fancy. One is always different form the other two and is called the lip or labellum. It may be pouch-shaped, ruffled, horned, bearded or wildly marked and spotted. The two side petals may also catch the eye - those of the mandarin orchid (Phragmipedium caudatum) twirl downwards in long ribbons.

The business of the flower is, of course, sexual reproduction, and orchids have their own unique approach. The male and female organs are fused into a cylindrical column, atop which sits the cap-like pollinia, holding millions of grains of pollen. In comes a bee, and off pops the pollinium, hitching a free ride to pollinate the next flower of its species. Flower and pollinator are perfectly matched, so it is not surprising that the huge number of pollinators (including bees, wasps, flies, ants, beetles, hummingbirds, bats and frogs) is equalled by just as many forms of orchids.

Orchids are not shy about crossing the other species (or genera) within their family, and gorgeous hybrids abound. Just as the children of the same parents are not identical, neither are all of the offspring from a particular cross (called a grex). Once a breeder has an outstanding plant, it must be propagated asexually (also called vegetatively), so that all new plants are identical (clones). With common garden plants, this can be done by taking cuttings or dividing roots. Not so with orchids (are you surprised?). A suitable laboratory technique called tissue culture was developed about 25 years ago. By taking a cluster of cells in a sterile environment and putting them onto a special growing medium in a test tube, hundreds of new plants can be coaxed along.

From an environmental point of view, hybrids and tissue culture are good news, because they allow our craving for orchids to be satisfied with plants that are not taken from the wild. (However, orchids are currently threatened by human development and the corresponding loss of suitable habitat in Asia, which is placing about a third of the world's species in danger of extinction.)

Over a cup of green tea, Carol Hsu shared her extensive knowledge of orchids. My curiosity was drawn first of all to the business itself. Oriental Orchids has a partner firm in Taiwan, where plants are hybridized and propagated by tissue culture. Young plantlets arrive from Taiwan bare-root, to prevent any soil-borne diseases from entering Canada. They are potted up at Oriental Orchids, where they may live for another three years in computer-controlled greenhouses. (Carol notes that young plants can be produced in less time, but they do not bear as many blossoms, nor do they flourish as well as older plants.) Despite their high-tech surroundings, each orchid is watered by hand. Once in bloom, plants go to market. The number of leaves and flowers determines the price. Most business is wholesale: through the United Flower Growers Auction, into the United States, to large hotels and florists.

Flower-show rosettes decorate Carol's office, attesting to the number of award-winning plants her family grows. Carol is most proud of their Award of Quality from the American Orchid Society, given to a hybridizer who can produce at least 12 high-quality clones from the same cross. An award-winning moth orchids has round, flat flowers of good colour and size that are well-spaced along the flower stem.

For the beginning (or lazy!) orchid grower, Carol recommends the moth orchids (Phalaenopsis) (see sidebar for care). Oncidium, Dendrobium and Cymbidium orchids also have beautiful flowers, but getting them to bloom again is challenging for the non-expert. Carol reminds me that in the wilds of Asia, moth orchids bloom in spring. "Come then, to see even more flowers," she says. I promise to return in spring for another visit to this tropical paradise in Burnaby.

Caring for Moth Orchids

Buy a plant with "perky" leaves. It is normal for the lowest leaf to gradually wither, but the new leaves should be plum, firm and rich green. The odd scar from shipping damage is of no concern.

Plants are usually purchased in bloom. Take your orchid right home. Never leave it in a hot car in the sun or a cold car in winter. At this stage, plants can tolerate low light conditions and cool temperatures, which will extend a flowering period that may last for months. (If you pop off the pollinium, the flower "thinks" it has been pollinated and will with right away.) Do not fertilize blooming plants, which will cause the buds to drop off. You can mist the leaves with room-temperature water, but never mist the flowers. Keep plants out of direct sunlight at all times.

Carol emphasizes, " My most important advice is 'Don't water too much!'" Plants should be moist but not wet. Before watering, test for moisture content by sliding a wooden chopstick five to eight centimetres below the surface. When the moisture content is about 20 per cent (when the chopstick feels slightly damp; the soil may be dry on the top), you can apply room-temperature water. If potted in bark, plants may only need water every three to five days in summer; if in moss, every seven to ten days. Water less frequently in winter.

Air circulation can be increased by using a small fan, and humidity can be increased by placing a pan of wet pebbles near (not beneath) the plants. Oriental Orchids has custom pots with vaulted drainage holes that allow air to circulate beneath the pot.

Once the flowers are finished, cut the flower stem down about halfway. Wait six to eight weeks - a new flower stem may emerge. If not, cut it off at the base. This is a signal to the plant that it can resume leaf and root growth. Water with a mild solution of 20-20-20 every second watering. While plants are growing, warm daytime temperatures (20° to 25°C) are required. The trick to getting moth orchids to bloom again is to reduce the nighttime temperatures by at least 5° to 8°C. The ideal position might be a south-facing room that warms up during the day but is unheated at night. Remember - no direct light. Screen the sun with sheer curtains or keep pots back from the window.

Carolyn Jones is the horticulturist at VanDusen Botanical Garden and author of Bedding Plants and Perennials, published by Whitecap Books.

Article from: Winter 2001 issue of GardenWise magazine (Volume 17, Number 10, pp.34-37)

Photos by John Glover / gardenIMAGE: Phalaenopsis hybrid and Michael LeGeyt: Coelogyne corymbosa.

 
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