Angraecum didieri turning black. Leaves dropping. - Orchid Board

junebug's orchids · #1 02-27-2018, 03:49 AM

So, my Angraecum is doing terribly. I don't know what happened. I missed a single watering on Saturday because I was out of town. Went to water it Sunday afternoon and I found it like this:

Leaves dropped and blackening, stem turning black, and most of the roots completely shriveled up.

I do still have one root that is looking really good.

It's very green after I water and appears to be growing some new warts. I have other orchids in this terrarium that are doing really well; my jewel orchids that survived the horrible shipping disaster, and a restrepia spp. sitting in a pot in there, until I figure out where I'm going to put it permanently (probably in a very large orchid vivarium I'm building right now, with my gecko for good measure haha).

The angreaecum was supposed to be the centerpiece in this tank so I'm pretty bummed it appears to be dying and I didn't want to stress it even more by re-mounting it.

Is there anything I can do to save it? Is this really from just one day of missed watering/misting? I have been diligent about misting it every day. If one missed watering really caused this I'm going to be very annoyed.

Ray · #2 02-27-2018, 08:40 AM

Looks like erwinia to me. Not caused by the water - or missing a watering - but very easily spread by splashing.

I would get rid of that plant immediately, and treat the tank with a topical disinfectant like Physan.

katrina · #3 02-27-2018, 08:47 AM

From the sounds of it, you kept it too wet. Ang didieri likes to dry out a bit between waterings...even more so during the winter months. It's very intolerant of constantly wet roots.

Dollythehun · #4 02-27-2018, 09:12 AM

Quote:

Originally Posted by katrina

From the sounds of it, you kept it too wet. Ang didieri likes to dry out a bit between waterings...even more so during the winter months. It's very intolerant of constantly wet roots.

So, Katrina, how do you grow this? I understand they love to be potted in charcoal. Now I've learned the wet/dry cycle and I understand bright light? Do you have tips? I just brought one home from Hausermann's.

Leafmite · #5 02-27-2018, 01:58 PM

Once these things get a fungus, there is really nothing that can be done to save them. As said, if they cannot dry quickly and conditions are cool, it is not wise to get water on the leaves. They come from breezy Madagascar and just don't have much natural resistance to fungus. If you replace it, it helps to make certain it has a good, steady source of Calcium. I found that this has helped. I also prefer growing this in plastic Vanda baskets with a large, chunky medium. If you do mount them, it can be more difficult to keep the leaves dry. Of course, if you have warm conditions and a small fan, there is no problem with getting the leaves damp. If you have cool conditions, though....

Another interesting thing about many Angraecums is that they are sensitive to fertilizer. Using too much fertilizer or not flushing the pots well can easily kill them. It is best to use rain water/distilled water with Calcium added and, to fertilize, use a very weak solution (and, as indicated, flush well) or use a slow release formula like Osmocote that will not burn the roots. The fertilizer won't kill the orchid instantly but will, at some point, cause a rapid decline.

Some people just always use a fungicide as a preventive for these.

I don't currently have any as the three that I grew for many years succumbed to this same problem one cool, wet summer when I was busy and not only left the three didieri hanging where they would get rain but also forgot to ensure a steady supply of Calcium. I am finally replacing them (from Hausermann's).

Here is a good blog of someone who grows these in Florida.

Angraecums...

The Encyclopedia Angraecum site is no longer up.

Dollythehun · #6 02-27-2018, 02:33 PM

Interesting sure, Leafmite, thanks. I understand it likes to be potted in charcoal. Mine is sitting in a south window with my new Dendrobiums. (The window is screened). I've been wondering how to pot it. I'm open to suggestions

Leafmite · #7 02-27-2018, 04:33 PM

I have never heard of them liking charcoal but I have no experience with charcoal so I would not know its properties. Perhaps charcoal is suggested so that one doesn't need to transplant them again. Many Angraecums have a reputation for not faring well after a transplant.

I have mostly seen them in empty baskets or mounted. What is probably most important is that the roots have good access to air so there are not worries about fungus or Phytophthora. Fungus and Phytophthora are the main reason that one needs to take precautions when transplanting. When transplanting them soak well to soften the roots, be gentle when removing the old medium, then place in DRY medium and leave dry for a few days to allow the roots to heal.

I will probably try adding Plaster of Paris to the red lava rock to give a steady source of Calcium. Maybe the Cattleyas will benefit from this idea, too.

---------- Post added at 03:33 PM ---------- Previous post was at 03:31 PM ----------

Junebug, I just wanted to let you know that I am sorry to hear about your didieri. I went through it, too, after growing mine for many years, and it happens sometimes. I hope you will try again as these are great little orchids.

Roberta · #8 02-27-2018, 04:48 PM

Only advantage of charcoal that I can see is that it doesn't stay wet - one could get the same result with LECA or rocks or large bark or bare root. For what it is worth, I have found that they grow very nicely outside at my house, essentially bare root... which says that they like to be on the cool side especially at night, to dry out, and have lots of air movement - however that might be accomplished. (How one does that indoors will be different than my arrangement, but the resulting conditions need to be similar because that's what they seem to like.) For calcium, a little southern California tap water now and then will do the job - this particular species isn't all that fussy.

Dollythehun · #9 02-27-2018, 05:09 PM

"I will probably try adding Plaster of Paris to the red lava rock to give a steady source of Calcium. Maybe the Cattleyas will benefit from this idea, too"

You gave me the idea to use eggshells. I now crush them.onto of every pot of anything remotely Catt related.

Roberta, the charcoal idea was on the Orchid web site. His video featured a huge one and he said they loved to be potted in.charcoal. I have a 4" mesh basket that I'm.going to use and thanks for the tip on the dry material. Air circulation around here is usually good.

---------- Post added at 03:09 PM ---------- Previous post was at 03:05 PM ----------

Angraecum didieri "Third Time's A Charm"

Well, sad to say mine got soaked in Kelpmax when it came home. It looked ok this morning. I do not want to mount this, to much headache in the house but, I can give it exceptional drainage. So, bright, good circulation, damp, not soggy. I actually bought this by mistake....again. But it was on my wish list.

Nexogen · #10 02-27-2018, 05:19 PM

I have two Angraecum didieri plants; I keep them in the terrarium, in sphagnum moss and with good ventilation. I use only RO water and found that the plant is very sensitive to the fertilizer, the leaves become black. I use a very rare fertilizer in a total of 25ppm.