Why are my Cattleya pseudobulbs turning brown?
Discoloration on any part of our orchids can be concerning, especially when it is seen on the plant structure of our Cattleyas! But before we jump to any negative conclusions, we want to be sure to rule out the common occurrence of shedding old sheaths most commonly found on orchids that produce pseudobulbs (like Cattleyas). We also created a video about this topic as an additional visual aid.
What are sheaths?
Sheaths are a protective layer of modified leaves appearing at the base of a young pseudobulb and enfolding all or most of it. When the pseudobulb is fully matured, the sheath will dry out, become paper-like, and will have served its purpose of protecting the young growth while it formed. Sheaths will then start to brown or blacken and become easy to peel off. Do not worry, this is completely normal. Much like our own skin after a sunburn or in time, the plant will also be ready to shed. At this point, it may be ideal to remove the sheath.
Why should we remove old sheaths?
1. Old sheaths can harbor pests.
Although the sheath may no longer protect the pseudobulb, pests like scales and mealybugs will glady find shelter under them.
2. Excess water can build up in and under the sheath and begin to rot the plant.
Not the most common of situations but possible and something we’ve witnessed personally. Depending on the environment and the routine of your care, water can get trapped in old sheaths and begin to pool. In the case that the weather is not ideal and the water does not evaporate in time, there is a chance that the pseudobulb may develop rot where it has not been able to dry.
3. Dried, dead sheaths can begin to mold and may not be beneficial to your plant.
Again, not the most common but seen when the weather is not the most ideal and the air is stagnant.
How to properly remove the sheath?
There are many methods to safely remove the sheath but the main thing we want to emphasize is that the sheath must only be removed once it is fully dried.
DO NOT PEEL THE SHEATH WHEN IT IS STILL GREEN!!
Premature peeling of new sheaths can expose the immature outer plant wall structures of the growing pseudobulb to danger and damage. First and foremost, determine that the sheath is ready to be removed. Then you may carefully begin to peel it off as much as possible. One method we’ve found helpful for removing the more stubborn bits of tissue is to use a wet clean washcloth and wipe down the pseudobulb.
If your cattleya pseudobulb is discolored but it is NOT the sheath, then there is certainly something wrong with the pseudobulb.
In this case, we'll need to determine the cause. We will go into depth on this issue in another article but for now take note of your current care regimen. How much water are your giving your cattleya and how frequently? Is your orchid being left sitting in water and not being able to properly dry in between? After you've gathered the information, please do reach out to us so we can help you further.