Yellow leaves on unknown dendrobium

[AussieGrower123]

Hello!
My first post here. I'm a relatively new grower from Australia and I'd very much appreciate advice on what to do with one of my dendrobiums. For a while, it seemed very happy in my orchid house but now it's got an abundance of yellow leaves and a fading of the green leaves. Please see the images attached. It had about 8 kikis on it - all healthy at one point but these seem to have died back.

I picked this thing up from a private nursery - not sure what sort of den it is but I do know there's more than one in there (I bought it in flower - some flowers were pink and white and some were pink and yellow). Can anyone suggest what might be going wrong and what I can do to rescue these plants?
Thanks much!
AG123

[SaraJean]

Hi there!
Don’t worry about this orchid. It’s not dying. You’re in Australia, right? And it’s late Autumn there? This Dendrobium looks a lot like my Dendrobium loddigesii. I can not tell you if that is exactly what yours is. But I can say that yours is either a nobile or semi-nobile type. Do a google search for more in-depth care instructions, both types are cared for the same. The Dendrobium genus is huge, and covers a massive swath of the globe, it’s broken into several sections or types. FYI:you can’t care for every Dendrobium “like a Dendrobium”

These go dormant in the winter. Starting in the mid to late Autumn the leaves will start to yellow and drop. By the late Winter, most of their leaves should be gone. Many people completely withhold water during the fall and winter months (for a plant this size you could probably do this if you have decent humidity, so you could stop watering now). They need cool winter nights and very, very bright light. Don’t resume watering until after buds set in the spring.

[estación seca]

Welcome to the Orchid Board!

Yes, this kind of Dendrobium drops leaves in autumn. Others don't. You can read a lot here on Orchid Board perusing old threads. Use the top maroon menu to Search on the name SaraJean mentioned, Dendrobium loddigesii. Also Dendrobium nobile, its close relative. Their hybrids behave very much like these ancestors.

[AussieGrower123]

SaraJean and estacion seca - thank you!! Thanks for replying so quickly with such great information. I now have hope that these plants will come good in the spring.

Also, thanks for the identification help - I bought this as an unnamed orchid, so it's great to finally know what it is.

Just to clarify - when you say 'withold water', do you mean keep it out of all rain or just don't go applying any extra water?

Again, I appreciate your time and knowledge!

AG123

[estación seca]

Originally Posted by AussieGrower123

...Also, thanks for the identification help - I bought this as an unnamed orchid, so it's great to finally know what it is.

Just to clarify - when you say 'withold water', do you mean keep it out of all rain or just don't go applying any extra water?

You're welcome. You still have an unidentified orchid. When it blooms, if it's not clearly a recognizable species, it will remain unidentified. But you now have some idea of its cultivation needs because you know which type of Dendrobium it is.

As to winter rain - there is a lot of argument about how much winter water to give this type of Dendrobium. The Huntington Botanical Gardens in metropolitan Los Angeles has a climate not too far from Sydney, and they leave their Den. loddigesii out exposed to the rain in winter. They flower wonderfully.