Botanical Name: Oncidium species and hybrids
Most oncidium orchid species produce dozens of small flowers at the same time, giving a spectacular show that lasts for several weeks. The large-lipped flowers may be yellow, white, red, pink, green or brown.
The flowers vary greatly, but share one common feature: the large lower petal, called a lip, is always perpendicular to the side winged petals.
The distinctive shape of the blooms, carried on many-branched stems give oncidium orchid its common name: Dancing Lady Orchid. Oncidiums flutter in the breeze, making them "dance."
In the wild, almost all Oncidium (pronounced on-sid-ee-um) orchids are epiphytes, growing on tree branches where they anchor themselves with their thick roots. They like free-flowing air as in their native habitats. Put them where they'll enjoy air circulation, away from heat or AC vents.
Several hundred species exist, native to tropical and subtropical habitats, including the high Andes mountains, the humid forests of Jamaica, and the tropical river valleys of Brazil, Ecuador and Peru.
What these dancing sprays of flowers have in common is a love of humidity. If the relative humidity drops below 50%, use a pebble tray or room humidifier to increase the moisture in the air. Grouping plants also helps to maintain the humidity around them. You can mist the foliage every day -- they won't mind.
Most oncidiums you'll find are hybrids, involving several species. These complex hybrids produce more flowers, bloom more often, and grow faster than the species. Oncidium hybrids offer some gorgeous varieties.
O. varicosum, shown above, is a popular species, producing a shower of bright, sunny blooms.
Oncidium papilio, shown at right, is called the Butterfly Orchid. This is one of the few orchids that bloom in succession, a flower at a time, from spring through autumn. Spectacular colors and easy to grow -- what's not to love?
'Sharry Baby' shown below, is an easy orchid for beginners, offering a profusion of red and white, sweetly scented flowers.
Shed some light. Oncidium orchid plants need plenty of light, but not direct sun. If you don't have a spot near a window, artificial lighting works beautifully. Fluorescent bulbs are efficient. Use 1 warm white tube and 1 cool white tube under a reflector. Place orchids about 6 inches (20 cm) beneath the light for 14-16 hours a day. It's also important to give them darkness at night. Plants need a rest, too.
To repot...or not. Fir bark medium breaks down after a couple years and needs replaced. The best time to repot your orchid is when new growth begins, shortly after blooming.
Got a reluctant bloomer? Give your orchid slightly cooler nighttime temperatures to spark blooming. A 15° difference will do. Oncidiums will tolerate varying temperatures from 55° nights up to 75° days. Blooming time varies by species and some give more than 1 show of blooms throughout the year. With good oncidium orchid care, you can expect blooms year after year.
Origin: Most from South America
Height: Species vary widely -- many range from 12-30 in (30-75 cm).
Light: Good orchid care also includes bright, indirect sunlight. Don't have space near a bright window? Fluorescent lights work well, too.
Water: Keep the medium lightly moist during the growing season. Be careful not to overwater. Oncidiums store water in their pseudobulbs, making them more tolerant of dry soil than wet. Water less during other times of the year, allowing soil to become almost completely dry between thorough waterings.
Humidity: Moderate, preferably 50-60% relative humidity. Use a humidity tray or room humidifier, if needed.
Temperature: 55-60°F/13-16°C nights and 65-75°F/18-24°C days; slightly cooler nights will help these beauties bloom.
Soil: Orchid potting mix
Fertilizer: Feed during active growth every 3 weeks with an organic orchid fertilizer.
Propagation: Division. Divide into clumps of at least 4 pseudobulbs each.