Cymbidium with yellow pseudobulbs

[david meyer]

Hi all. I have a cymbidium that has yellow pseudo-bulbs and the lower part of the leaves are also yellow. Recently I found one new shoot rotted. Another new shoot is yellowing from the bottom also. I have attached a photo. This orchid did not flower this year or last. The yellowing was present to a lesser degree last year. I think another orchid is developing the same problem.

Can anyone help?

[estación seca]

Welcome to the Orchid Board!

The yellowing could be normal if you're growing it in lots of sun. They make new growth in late winter to early spring, now for you. Cyms lose older pseudobulbs eventually. The newer pseudobulbs are smaller than the old, indicating it isn't getting everything it needs.

It looks as though it hasn't been repotted in a long time. They like a loose potting mix that never dries completely, plenty of sun and regular fertilizer. Flowering is triggered by cool night temperatures in the winter and fall months before flowers appear.

There is a Cymbidium forum here. From the left yellow menu select Forums and scroll down. There is a lot of good information.

[Roberta]

First, Welcome!
My first inclination would be to get it out of the pot and find out what is going on with the roots. Spring is the ideal time to repot Cyms, though I do it pretty much through most of the summer as well. So timing is good. If the plant hasn't been repotted within the last 3 years, it probably needs it. Cyms are also heavy feeders - I use time-release fertilizer with them in addition to giving a drink of my regular fertilizer solution, and that seems to have helped a lot as well.

I know that parts of Australia are already seeing summer-like heat. If you're getting into that "above 35 deg C" range, consider some shade cloth as well. Cyms are tough, but they do have limits. When I first moved to my house, I had Cyms completely unprotected, but when I added light shade cloth (about 45%) they responded quite favorably. Especially that helps if they're getting toasted all day. I have very little shade, in an east-west yard, so in summer, it's about 13-14 hours of intense sun, that turned out to be at the upper edge of their tolerance so taking the edge off with shadecloth was beneficial.

[david meyer]

Thanks for the help. Re-potting is on the agenda.

[david meyer]

We have relatively cool weather this week (20's C) so re-potting is planned.
The orchid is easily removed from the pot. See attached photos. Some roots look a little browner than others (I assume older). Does anyone see anything obviously wrong?

[david meyer]

Also, should I divide it?

[Roberta]

New roots look great. The ones in the middle of the pot may be less good, hard to tell. If that were my plant, I would take as much of the old medium off as I could do fairly easily, then give it a good blast with a hose to get some more. The plant looks pretty substantial, so this would probably be a good time to divide. Make sure that the divisions have at least 3-5 pseudobulbs. It looks like you have plenty. When you get it apart, you will probably have some old back bulbs in the middle that can be discarded - again, though, make sure that each division has the minimum number of pseudobulbs (firm leafless backbulbs count) When the the mass opened up to divide, it will be easier to clean out the the middle. I leave old roots that don't come off with a good tug, though you can trim obviously bad ones too. Also... I find that I cause less damage to roots when I divide if I can find a weak spot and break the mass rather than cutting (you might have to make a cut to start things... your hands are probably stronger than mine, though) When you add the new medium, add a little at a time, tap the pot to get it in between the roots, pack it down with your hands or thumbs, then add some more and repeat. You do want the plant to be firm in the pot. (If you can pick up the newly potted plant by the leaves and it doesn't fall out, you have done it right) Then, having gotten your exercise for the day, a nice cool beer might be in order.

[david meyer]

Thanks Roberta! This will actually be the easiest job of the day.
Some of the older roots look a bit grey and when I hose the roots just now, they look like they are dead I think. I am left with a thin internal cord.

FYI, last year was the end of a very bad drought and we had some kangaroos come to eat the last of my lawn. They still visit regularly even now that we have had a good year for rain. Yesterday one female was feeding int he back yard with a fairly large joey in her pouch.

We are a little way from the bush, so she has to come through a few yard to get here.

[Roberta]

Oh wow! Very, cute, but I am sure annoying too. If you have plenty of good roots, no harm in clipping the bad ones. The ones from the new growths look excellent.

[david meyer]

Our back yard is a bit wild, so they are welcome.

It split is 2 easily and there were a lot of dead roots in the centre.