Question
QUESTION: Hi Wayne,

I cut the flower stem spike of my Dendrobium Orchid after it finished blooming.  I cut it above where the first flower was.  However, the larger stem is starting to turn brown no.  Do I cut that back as well?  If so, where do I cut it?  Is it normal for it to start turning brown?  If not, what can I do to prevent it from happening again if my plant is still savable?  

Thank you,
Melanie

ANSWER: Dendrobiums grow on canes.  However, when they flower, they flower from what are called flower spikes.  Sometimes, the flower spikes may branch.  Buds and flowers may emerge from either or both flower spikes and their branches.  It is normal for both flower spikes and their branches to turn brown and die after flowering and may be removed by cutting them off in any location (except for the cane) without damage to the plant.

The plant itself grows in the form of canes.  If a cane turns brown, that is not normal and is a serious problem usually due to a bacterium or fungus.  If it is the latter (ie the cane), then we need to discuss what to do.



---------- FOLLOW-UP ----------

QUESTION: It looks like it is the cane that is turning brown.  How do I go about treating the bacterium or fungus? Can my plant still be saved?

Answer
If it is only one of a number of canes, you may be able to save the plant.  You need to cut the cane off with a sharp instrument well below the point where it is turning brown.  You need to remove all parts of the cane that show any brown in the tissue.  Your cut needs to reveal only tissue that is completely green.  If you still see some brown, you need to cut off more of the cane until you finally arrive at all green tissue.  The cut end of the cane needs to be treated with a fungicide.  I prefer powdered sulphur but your garden center may have other fungicidal powders that you can smear on the cut end.  Then, you need to suspend watering or misting until the cut end is healed and there is no more sign of fungus.  Actually, you shouldn't be watering your dendrobium during its rest period so this should work well.  The rest period usually begins shortly after cessstion of flowering.  During rest (when there is no sign of new growth), watering a dendrobium can contribute to loss of the plant.  Do not resume watering until you see new growth at the base of the plant.