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.

Orchid pseudobulbOrchid pseudobulbs and leaves

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.

Dendrobium stem and leavesMiltonia pseudobulb and leaves

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.

Cattleya pseudobulbs and leavesCattleya pseudobulbs with dry sheaths

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

Subscribe to the About Orchids Blog:
AddThis Feed Button

Both comments and pings are currently closed.

11 Comments on “Pseudobulb”

  1. Rita Davis Says:

    Maybe it should be “sue doh bulb”

  2. Wendy K Says:

    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!

  3. joel300 Says:

    good photos – worth 1000 words

  4. Dennis Says:

    Good article.

  5. AboutOrchids » Blog Archive » Winter Orchid Care Says:

    […] Resist the urge to water until you see their pseudobulbs start to shrivel. […]

  6. Gwen Says:

    good post thanks

  7. ChoownBor Says:

    Just want to say what a great blog you got here!
    I’ve been around for quite a lot of time, but finally decided to show my appreciation of your work!

    Thumbs up, and keep it going!


  8. AboutOrchids » Blog Archive » Thunia Says:

    […] 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.[…]

  9. AboutOrchids » Blog Archive » Little Purple Stars Says:

    […] plants can dry out quickly in high temps or high winds, and Lepanthopsis has thin roots and no pseudobulbs. […]

  10. AboutOrchids » Blog Archive » Equinox Says:

    […] Many orchids are heading into dormancy. Start to reduce watering for orchids with pseudobulbs, like Cattleyas, Cymbidiums, Dendrobiums, Epidendrums, Miltonias, Odontoglossums, Oncidiums, and Vandas.[…]

  11. AboutOrchids » Blog Archive » How to Kill An Orchid Says:

    […] 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 […]