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This article was published 1/3/2013 (1423 days ago), so information in it may no longer be current.
Exotic, mysterious, fascinating -- these are just a few of the adjectives used to describe orchids. They're found on every continent except Antarctica, with more than 30,000 naturally occurring species that have been described. In addition to the wild orchids there are another 100,000 or more man-made hybrids.
The largest orchid on record is a plant in Brazil that stands 2.5 metres tall, while the smallest plant (discovered growing among the roots of other orchids) has flowers only 2.1 mm wide.
The genus dendrobium, with more than 1,200 species worldwide, is the second-largest genera and one of the most diverse orchid families. Some species of dendrobium have flowers that look like insects; others look much like the common phalaenopsis orchid. Some are tiny, while others are very large; some grow upright while others are pendulant.
Flower colour varies to include almost every colour in the rainbow, ranging from shades of pink, orange, yellow, green and violet. While some species keep their leaves year-round, others may drop their leaves at specific times of the year. A number of species are delightfully fragrant while others have a delicate or an absence of fragrance.
Dendrobiums favour tropical to subtropical climates, and New Guinea is the centre of the natural distribution. Preferred habitat ranges from the South Pacific islands, extending west to India, south to Australia, and east to Samoa and north to Japan and Korea. Alternatively, a number of species prefer cooler temperatures and are found at higher elevations.
In the wild, dendrobiums grow as an epiphyte, attached to the branches of trees. Here they receive dappled sunlight, are fed dilute solutions of natural fertilizer during periods of rain and have ample air movement around the roots and leaves ensuring vigorous plants.
Fortunately, small species like D. rigidum at 10 cm in size, to larger species including D. pierardii with its 30- to 60-cm canes, can, if given appropriate conditions, be successfully grown in our homes. In addition, a large number of hybrids suited to windowsill and sunroom culture have been developed and are available.
To grow dendrobiums successfully, we have to try to emulate, as much as possible, the conditions they prefer in the wild. A popular growing media for these orchids is comprised of medium-sized coconut husk chips or fir bark mixed with sponge rock. All of these ingredients are available at your local garden centre. Tropical orchids do not do well in soil-based mixes.
The recommended growing containers are clay pots. They are porous and breathe, allowing the medium to dry within a reasonable period of time. Other types of pots can be used providing drainage is sufficient to ensure the roots do not remain wet for extended periods of time.
Most dendrobium species and hybrids can be grown outside during the summer. In late spring or early summer the plants should be placed outdoors in a location that receives good light and air movement. Hanging them in a tree works well for those plants that have a pendulant form, while those that grow upright can be placed on a stand.
Ensure the orchids are provided with shade during the hottest part of the day (noon to 4 p.m.). While plants are in their growth phase, water regularly at least twice a week, or more often in hot dry weather.
Fertilizer should be added to one watering during the week. Use an orchid fertilizer or other all-purpose fertilizer (10-10-10) at approximately one half the recommended strength. In the later part of the summer, as new growth begins to mature, change to a blossom booster fertilizer, also at half the recommended strength.
In September, reduce watering to no more than once a week and the fertilizer application to every second week. As night temperatures drop to 10 C or 12 C, move the plants to an indoor location with good light.
The Nobile types (a medium-sized dendrobium known for providing an excellent show of flowers in late winter or early spring) should be treated slightly differently. Grow them in a shaded location outdoors during the summer, using an all-purpose fertilizer at half the recommended strength. In the autumn, allow them to be exposed to full sun and switch to a blossom booster fertilizer at half the recommended strength.
Water normally to prevent shrivelling of the canes. Flower buds will form as the night temperature cools. Just prior to the first frost, move them indoors.
Check carefully for insects that may have colonized the orchid during the summer. Scale insects appear as a very small brown bump and exude a sticky secretion on the stems and leaves. These pests are commonly found on ornamental trees and shrubs. When an infestation is detected, this serious pest should be treated with an approved insecticide, best done prior to moving the plants indoors. As an alternative to using an insecticide, a cotton swab with rubbing alcohol can achieve control. Check your plants regularly, preferably at least once a week.
While your orchids are in bloom, take advantage of the opportunity to photograph your favourites. Close-up portraits of individual flowers are best taken just as they fully open. For outdoor plants blooming in the summer or fall, choose a calm day during a period of light cloud. This offers a pleasant diffused light for optimum results. In the winter, try setting up in a location near a window where you have bright light but can avoid harsh direct sunlight.
Because of the vast array of dendrobium species and hybrids available, it's important to purchase plants from a knowledgeable vendor. Advise the vendor of the growing conditions you can provide in your home and request a recommendation of appropriate species or hybrids for your conditions. Conversely, if you desire a particular species or hybrid, ask the vendor to describe the conditions this particular plant requires.
The annual orchid show is an excellent opportunity to purchase plants from orchid vendors invited from different locations in Canada. These vendors not only have an excellent assortment of plants, but they also are a valuable source of cultural information in respect to the plants they sell.
How many of your houseplants produce a bloom that can last six to eight weeks? For that matter, how many of your outdoor plants produce blooms that last several weeks before they release themselves from their delicate or sturdy stems and waft slowly to the ground or get carried away on a summer breeze?
Orchids produce some of the longest-lasting, most exquisite blooms. When the plants are mature, blooms on multiple canes create a show-stopping display. Your indoor orchids can also enjoy a summer vacation.
For a unique outdoor container display during the growing season, simply locate them in a shady, protected spot in your garden. Once all of the flowers have dropped from the flower spike, cut the spike back to where it emerged from the cane.
The orchid's complex beauty can sometimes be intimidating. Talk to the experts at the annual Orchid Show and Sale March 22 to March 24th at the Assiniboine Park Conservatory and you will soon be persuaded there is an orchid for everyone. Today's contributor is Lorne Heshka, past president of the Manitoba Orchid Society.
Interested in joining the Orchid Society? Members and guest speakers share their expertise and also sell orchids at the monthly meetings. Meetings are held on Sunday afternoons from September through June. For more information visit the Manitoba Orchid Society website at www.manitobaorchidsociety.ca.
Interested in local food? Plan to attend the 2013 Growing Local Conference, hosted by Food Matters Manitoba for everything from aquaponics to zesty salads. Displays and workshops. Today, at The Marlborough Hotel, 331 Smith Street. 7:45 a.m. to 5 p.m. For more details visit firstname.lastname@example.org.