D is for difficult Dendrobiums
 

I've been growing for a few years now. Maybe 3. It really seems like longer than that, but maybe not. I don't feel like I'm a great grower, but I now feel like I can diagnose and remedy problems with my Phalaenopsis, my Cattleyas, and my Oncidiums. But Dendrobiums are so difficult!

I have a D. biggibum compactum that grows, but barely, and while I've been out of town, one of its growths has died off. I have two TJ's Den phal types that have yellowed and lost a few leaves since I brought them home, although one is producing keikis or more flower stalks beside the flower stalk it already has. I have a nobile backbulb that someone gifted me that was growing a new cane, but that one croaked as soon as it came into my care. And I have another Den phal that has really struggled the two years I've had it, that got burned when I brought it to LA, and that now is growing 7 new canes! I have a Den. Stardust 'Firebird' 4N that I've gotten to grow and bloom before, but this time of year it always loses some leaves and looks kind of crappy. It looks so scraggly and unkempt compared to photos I see of this plant. I just noticed that it has spider mites, so once I get some alcohol and kill those, perhaps it will look better.

I grow my plants in LECA, so they drain well. I grow them now in a windowsill where my B. nodosa and some of my more tender mini-Catts are happy (Pot. Love tapestry and Lc. Cluster Fire 'Cinnabar'), but also my Phal. Donna's delight is doing ok there with them, so I don't think it's too much light for Dens. I think I will just end up seeing what lives with me and what doesn't, but I feel like it's such a shot in the dark with these Dens and I have no idea what I'm doing! :lol:

Personally I am not a fan of all LECA. In particular for Dens, which should be grown in tiny pots. Since each new growth only requires 1/2" or so, you do not need large pots.

If a Phal (needs abt 60% shade) does well in a given window, I would think that it is too low light for both Catts & Dens (both of which do well with 35-45% shade).

Den nobile types need cool, very bright and relatively dry conditions from Oct to March. Then ramp up watering & fertilizer, and move to same shade level as Catts.

Den Phal types prefer somewhat warmer (= intermediate to warm) temps year round, a little less water (but not actually dry conditions) in Dec-mid Feb. Reduce fertilizer a bit during winter too. They can be grown in bright to Catt light levels.
I tried one outdoors in full sun in NJ last summer. It was too bright, but only by a little. These can be grown in as little as 20% shade.

I know how you feel. Some of them can be so frustrating! I just failed with my first attempt of the Latouria types. I killed all three. I did replace the Microchip (which I water daily and now grow in a table-top greenhouse that sit on a heating pad) which is finally thriving.
Then there is that new Phal-type Den. It got knocked over twice and the second time, the roots were damaged (it is under the lights and getting a new growth so it will be alright). Some Phal-Dens really hate their roots being disturbed and react badly. I had one that always lost a few bottom leaves every time I moved it outside for spring and inside for autumn. Still, very frustrating.

I don't grow the nobile types but I do grow a few odd species and have grown the Phal-types (and now the Microchip). It is a really large group and they come from quite a few different climates so they tend to have different needs.

The Phal-types are pretty easy (once they get established in LECA or red lava rock). They like to be warm (above 60'F), they prefer Cattleya light, they like a medium that lets plenty of air to the roots and when watering, soak their roots until they turn green. I grew them in clay pots in the beginning but use basket pots for the one I have now. That way, when it gets huge, I can just set the basket in a larger one and add medium.
I have found it best to try not to get water on the new growths as they might rot if conditions are right. I also find it best to plant the Dendrobium on top of the medium and stake it well until it is established (again so the new growths have a chance at living). They bloom on old growths so don't remove those as long as they are green.

I have grown the nobile types. They like strong light, tons of water and fertilizer during the summer, and then, in the fall, very, very little water and no fertilizer. I don't grow them now because they lose their leaves but you can't just shove them in a dark place and forget about them until spring like Pleiones or the Cyncnoches. Again, you have to watch that the new growths don't rot due to water getting in the growths and sitting there.

Then there are the many other types..... :)
I hope this helps. The Phal-types are really wonderful as many of them can be in bloom for most of the year. :) Good luck!

I live in L.A., been succesfully grown den. Phal and nobile. I've have a noid den. Phal that bloom almost year around. I grew my dens in south facing windows where it get afternoon sun. I also started to grow some along the balcony, but when temp. Reaches tripple digits in L.A., it gets horrible sun burn. I now put it over a shade curtain. It's been growing again. I water them daily in summber amd fall. Even now, I have to water them almost every other day, since L.A. is still very warm during the day and the low humidity is not helping. Anyways, I've grown my with barks and about half an inch moss for topping to keep the moisture. I have two noid den. Phal sending out spike after spike on both old and new canes. Hope that helps

I purchased a couple of den phals at TJ's not too long ago. The evening I brought them home, I inspected the roots & found just about no viable ones. I am glad your plants are showing signs of life!
I was planning on cutting the flower spikes off of mine tonight, to give them a chance to grow roots.

Margit

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You can soak it in seaweed/kelp solution to promote new root growth.

My Dens thrive without any special treatment. I live in an area where the humidity is almost always over 60% and the daytime temp ranges from 30 to 35C (86 to 95F) in summer and sits around 20C (68F) in winter. I think your medium would be too dry for them especially the biggibum which is from a warm damp habitat.

This is a pic of my nobile in full rebloom in August (my winter). It was taken in the afternoon shade so it's in quite bright light all day. I hope this helps a little.

Thanks! I have read about the various types and their care requirements, and I agree that I wouldn't expect a Phal and a Den to do well in the same place. I keep thinking the Phal will burn up and I keep a close eye on it. They are all in an east-facing windowsill shelf, but it's in a corner where there are also two south-facing windows side by side. The Phals are in the northernmost part of the shelf, one Phal is set very deep in its pot, and the others two are shaded from the south by that pot, so they really only get light from the east in the morning. The Dens and Catts are placed south of the Phals, and my other phals and Oncidiums are on the west wall of the room, at least a foot away from the south facing windows (the Phals are shaded from direct sun by the Oncidiums). The Dens and the Catts actually have little isolated spots of sunburn from earlier in the year when the light was much stronger (that I don't worry too much about because they were just small spots), and even over the last month as the angle and distribution of the light changed in the room, one of my Phals on the west wall got burned up dead (My Phal. speciosa C1 :() while I wasn't here to realize that it was in the sun mid-day and that was why it was suddenly doing poorly. So I don't think low light is my Den issue. It surely might have been when I lived in Boston, especially combined with the cold issue, but I don't think light is my main issue now.

Thanks! I think you might be onto something here. I always repot new plants. I have learned to grow in LECA and am not comfortable with other media. Plus, I HATE repotting and cleaning stuff off roots, so I like LECA for that reason. If they don't like to be repotted, that and some temporary adjustment may be why they always lose some leaves at the beginning. And it may explain why the one I've had for a couple of years (where it was too cold and didn't get enough light to make it really happy, but not so little that it died), is now really taking off! It was in LECA since I got it, and hasn't been disturbed since I arrived here in August.

Thanks! That does help! I think you might be onto something, too, which is maybe that I am underwatering them given my choice of substrate. I may need to water more until they develop good roots that dig down into the pot where the LECA stays moister. The newer ones did come in a much denser potting situation than I have them in now, so they are probably not used to being as hot and dry as they have been here. I'll step up my watering with the new ones!

It's helpful to know that Den phals are just a little touchy about change and that if I can figure out to give them what they want, they'll be floriferous here. I really like the way they present their flowers, so much so that they have become my favorites and if I can get good at them and get them to bloom much of the year, I could see phasing almost everything else out!

---------- Post added at 09:06 PM ---------- Previous post was at 09:04 PM ----------

It does! Two votes for I'm keeping them too dry! Thank you!

I love Dendrobiums, they're very pretty, extremely varied, and fascinating. But they don't get along with me for the most part, so I stopped trying. In fact, I consider it a major accomplishment that I managed to rebloom a Phal-type dend I've owned for over a decade .... even though it only produced 2 flowers, at least it's not dead, yet.

However, more recently I got a Dend. Microchip that's done really well in my conditions. I basically grow it a lot like a Phalaenopsis or Paphiopedilum. Water twice a week year round, but I'll give it an extra spritz if it's looking a little dry between waterings. It stays warm, but not hot year round, and it gets Phal/Paph level light.

The only issue I had with it was that it developed mites, but those were easily dealt with, and it recovered nicely. It seems to bloom and grow pretty reliably for me, in fact it is finishing up its last growth spurt and is already showing signs of producing flower spikes.

There are so many different Dendrobiums that you are bound to find some that will fit your conditions and tastes. :)