Dendrobium Leaves Turning Yellow & Falling Off

[scy]

Update: I sphaged and bagged the cane that fell off my dendrobium on Dec. 1st. 6 days later, a small nub started to form so I waited a while to see what would come of it. I opened the bag every day for a few minutes to let it get some fresh air and check for mold. When there was mold, I rinsed it off and put it back inside the bag. I did soak it in Physan prior to putting it in the bag.

Here's what it looks like now. When can I take it out of the bag? What do I do next?

[RosieC]

To me that looks like it may be a new cane starting, roots usually follow coming out the new cane.

Personally I would carry on with the sphag-n-bag you have been doing for a while longer, possibly until roots start to show. I've not done it before though so others may have different advice.

[scy]

Hi Rosie! I started a new thread in hopes that I may get more responses.

The new cane forming was originally there before the cane broke off. The only difference from before and after sphag and bag is the green nub in the picture. I think it's a new root but since I've never done sphag and bag, I was hoping for more advice.

[Orchid126]

Dendrobiums like as much sun as you can give them without burning the leaves. Here in NJ an east window with a curtain is not enough light. The plant is in the dark. Mine are in an unshaded west window right up against the cold glass, and they bloom. Many books recommend a sheer curtain, but they are not talking about the light starved northeast.

Without enough light to stimulate the leaves the plant can't utilize the water or fertilizer. The plants will sit in the wet medium and the roots will rot. Leaves dropping from the old cane is one thing, but the leaves dropping from the very young cane is quite another.

Also, the plant is overpotted. Dendrobiums like very tight shoes, to the point that they look top heavy. Too big a pot will allow for too much medium that will stay much too wet for the root system and cause the plant to suffer.

Also, dendrobiums don't like a lot of nitrogen.

Dendrobiums are pretty tenacious. Try making some changes and see what happens.

[RosieC]

Originally Posted by scy

Hi Rosie! I started a new thread in hopes that I may get more responses.

The new cane forming was originally there before the cane broke off. The only difference from before and after sphag and bag is the green nub in the picture. I think it's a new root but since I've never done sphag and bag, I was hoping for more advice.

The only green nub I can see is the one I think is a new cane.

There is the main cane, there is a much much shorter old cane, then there is a tiny green fresh looking nub, which I think is a new cane starting.

I could be wrong though

[quiltergal]

You're not wrong Rosie, it is a new cane starting. That is where new roots will come from once it gets a little bigger. Old canes normally do not grow new roots.

[scy]

I'm a little confused. Off the original plant, there was the main cane and 2 smaller canes. The cane I sphagged was the smallest of the group and came off the 2nd medium sized cane. What would constitute it as "old?" How can I tell what new roots will look like as I start to watch it grow?

[quiltergal]

Dendrobiums are rhizominous, meaning the canes are connected together by a rhizome. In the case of Dens like yours the rhizome is very short and pretty much invisible. The colony of canes are actually one plant. Sometimes when a plant suffers severe root rot, the rot extends to the rhizome as well and that is why your one small piece fell off the main plant. So, technically you now have 2 plants.

Most rhizominous plants have two growth "eyes". It's kind of emergency backup in case a new growth is damaged or diseased. The plant will "activate" the second growth eye in order to save itself. Any cane that has matured..(not growing any new leaves or has bloomed) is considered old growth and will not grow any new roots. New root growth always comes from new canes still growing.

Dendrobium roots are very slender and fine. The actively growing tips are bright green and shiny, and as the root elongates you will see white velamin (a sponge like root tissue which surrounds to root, that absorbs water and sends it to the root core). So look for small, shiny bright green nubbins to pop out near the base of that new cane.