Pseudobulb
Pseudo-what? That word is pseudobulb, pronounced “SOO-doh-bulb.” Like the bulbs of tulips and daffodils, orchid pseudobulbs store water and nutrients during the dormant season. Many popular orchids, like Cattleyas, Miltonias, and Oncidiums, have them at the bases of their leaves. Pseudobulbs come in a wide variety of forms. They can be egg-shaped, spherical, or flat. Some are smooth, while others are wrinkly. Dendrobium and Epidendrum pseudobulbs look like swollen stems.
No matter what they look like, pseudobulbs serve the same purpose: to provide a reserve of water and nutrients for the orchid. Some varieties can survive for months during a dry season in their native homes. To mimic this natural dormancy, growers can cut back on watering during fall and winter. Wait and watch for the pseudobulbs to shrivel slightly, and then water. Depending on other factors, such as light, temperature, humidity, and air movement, dormant orchids may only need water once or twice a month during winter.
Unlike tulip bulbs, orchid pseudobulbs need to be kept completely above the potting material. They’ll rot underneath bark or moss. The final picture shows a Cattleya with papery sheaths that are typical for some varieties. The sheaths start out green, but eventually dry and fall off.
Orchid varieties without these storage devices, such as Phals, Paphs, and Masdevallias, do not go truly dormant. However, with less light and cooler temperatures in winter, growers can cut back watering slightly. Maintain high humidity for all orchids during winter, whether they have pseudobulbs or not.
Explore posts in the same categories: Dormancy, Misc, Photos, Watering
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November 20th, 2009 at 8:48 pm
Maybe it should be “sue doh bulb”
December 2nd, 2009 at 9:56 pm
many years ago I bought an lovely oncidium. It bloomed for a while and then someone told me to repot it. I didn’t know much and just buried the plant up to lower leaves in bark. the whole thing quickly rotted but it wasn’t until a year later that i learned that the round part was a psuedobulb that needed to stay above the soil. Live and learn!
December 20th, 2009 at 10:59 pm
good photos – worth 1000 words
December 22nd, 2009 at 3:29 am
Good article.
December 27th, 2009 at 9:56 pm
[…] Resist the urge to water until you see their pseudobulbs start to shrivel. […]
March 10th, 2010 at 10:33 am
good post thanks
May 15th, 2010 at 9:56 am
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Cheers
Christian, iwspo.net
June 25th, 2010 at 1:52 pm
[…] New leaves emerge from the base of the previous year’s stalk (actually a pseudobulb,) and the new growth shoots up in just a few months.[…]
July 24th, 2010 at 1:49 pm
[…] plants can dry out quickly in high temps or high winds, and Lepanthopsis has thin roots and no pseudobulbs. […]
September 22nd, 2010 at 7:43 pm
[…] Many orchids are heading into dormancy. Start to reduce watering for orchids with pseudobulbs, like Cattleyas, Cymbidiums, Dendrobiums, Epidendrums, Miltonias, Odontoglossums, Oncidiums, and Vandas.[…]
October 6th, 2010 at 7:17 pm
[…] This method is very effective, however, during winter dormancy it may take months for orchids with pseudobulbs to die. If you’re trying to escape suspicion, you may want to dribble a few drops […]