Dendrobium with no flowers!

[Tarryn]

Hi everyone,
We bought a dendrobium from an orchid seller that we met at an orchid show last year. It's quite a big plant with lots of branches and in a beautiful hanging basket. We've put it on a good spot and since we've had it, it's almost doubled in size! I've even had 3 keiki's off it, but NO flowers!!!!
Is there anything I can do to stimulate the flower growth? I have been feeding it once a week and it should be flowering now as this is their season, but there are no flower spikes at all! I read on one of the forums here that some Den's don't produce flowers, just keiki's. is this true?

[katrina]

The usual reason for lack of flowers has to do w/not enough light but before we go down that path...let's start w/a few more specifics....

Do you know what kind of Dendrobium is it? There are a lot of different species and there are also a lot of different cultural requirements for this group.

Also, you say you have it in a good spot but what specifically do you mean? Is it in window? If so, what direction is that window? N, S, E, or W or some combo? Maybe you grow in a g/h or outside year round?

Just a few more specifics on how you're growing it might be helpful in determining what needs to be changed up or adjusted.

[Tarryn]

Thanks for the reply Katrina!
It's a dendrobian phalaenopsis. It's outside at the moment in a spot behind our house that gets good dappled morning sun (about 3 hours of sunshine). We live in a tropical coastal town that rarely see's temperatures dropping below 15 deg's in winter so we leave our orchids outside and daytime temps go to about 25-30 deg.
As I said in the post, we believe it to be a good spot because in the year that we've had it, it's almost doubled in size! Lots of new leaf stems have grown with beautiful leaves on it. I'll post a picture of it in a later thread.
It grew 2 keiki's that fell off (think the wind broke them off) and its got one on that's got little roots and we are leaving on until it gets bigger.

[WhiteRabbit]

If it's currently growing, you may need to wait until the new growth is mature, or nearly so, before it may spike.

I only have a couple small den-phals, so I don't know about all of them, but mine start spikes mid to late summer to bloom in autumn.

When last year did you get this one?

[FSUOrchids]

I have a feeling it's the type that needs a winter rest, and that's why it's not blooming.

[King_of_orchid_growing:)]

Dendrobium phalaenopsis, (I'm talking about the species here, not the hybrid types), does have a winter "dry out" in the wild. It still rains in the winter, but far, far less compared to late spring and summer.

So, for anybody growing Den phalaenopsis and has been watering them regularly even during the winter, you can actually save some money on water by just letting this species go much drier in the winter.

During the winter, you can drop the watering down to once every 2 - 3 weeks, and it'd be fine.

It is also mostly found as a lithophyte in nature, btw.

[Discus]

I don't really dry my hybrid phalaenopsis-type dendrobium on purpose (unlike some of the other dens in my collection); it's in a CHC mix, so I err on the side of slight dryness anyway (with the occasional heavy flood) - it's flowered twice in a row under my care. Our inland town is probably considerably colder than yours, but it's grown indoors (min 10ºC at night), so that may not be a factor. I greatly reduce fertilisation in the winter, which may be a factor, but I don't change the type of fertiliser (MSU formulation for pure water, 13-3-15-8Ca-2Mg, in RO water).

I haven't had keikis on mine either, but I get TONS of keikis on my Nobile-type dendrobiums (all decended from one plant) (lots of growth, no flowers) if I don't give them a winter rest.

Re: seasonal timing, mine blooms in autumn (and is now going to start dying off now, having been in bloom for a couple of months).

It is very unusual to find a plant that won't flower at all; they do this when there is something you're doing wrong in keeping it (too much of something, not enough of another).

Some people have noticed in nobile type dendrobiums that it's not so much a break in water they need, but a break in nitrogen (fertiliser) over the winter to trigger their flowering. Try not fertilising it from now until spring and see how you get along; you can reduce watering too, making sure to water it if the pseudobulbs show evidence of excessive shrinking. I'm not sure if this will work with yours, but it's worth a shot. Many dens also respond well to an increase in sunlight in winter; without knowing the (probably) hybrid ancestry of your plant, it's hard to know what it will see as a "trigger" - and in some crosses, only testing our various things will reveal what it is!



---------- Post added at 06:43 PM ---------- Previous post was at 06:21 PM ----------

It may be worth finding a local(ish) orchid Fundi who has some experience with growing these in your climate; there are a couple of nurseries over that way (Stephward in Uvongo, Inhle in ?Ballito? and Colin Silver at Stone Age in Durban); there are several orchid societies there, and I'm sure someone in one of those grows these in a garden similar to yours! Orchid Societies Affilliatedto the SAOC

[King_of_orchid_growing:)]

It's not necessary to do the "dry winter" for Den Phal hybrids. But since it was brought up, I know that the species Den phalaenopsis does have a "dry spell". Some people don't observe it for the species as well, but I'm just saying that it's possible, and it could be a way to save some water, time, and money.

In cultivation, yes, as Discus did mentioned, the fertilization of the orchid stops altogether.

Since everybody here is kinda guessing at how to solve the problem with your Dendrobium without actually seeing what the plant looks like, is it possible to post a photo of it?

Why people observe the reduction in watering for the Dendrobiums that go through distinct dry seasons, is not necessarily for the sole purpose of triggering blooms. It is a way to indirectly stop fertilization, (most orchid fertilizers are water soluble fertilizers), and also because watering during winter, depending on the circumstances of how it was grown/potted, has the potential to add the problem of rotting your plants out if done just as regularly as during growing season. For me, I'll throw in that it saves me time to reduce the water for those that experience the dry spell.

[pipsxlch]

While I do give my hardcane dens a winter drier rest, I'm going to go off into a different direction and guess it may want more light.
I grow mine getting dappled light a good 6+ hours a day, a fair bit of it pretty direct. I've had plants refuse to bloom when moved to more shade, then start again when moved to higher light.
It didn't affect their keiki throwing, though.

[Tarryn]

Thanks everyone for the advise. For the past month I have already reduced the watering it received and it didn't look happy. The stems have gone a bit limp so I've resumed it's normal routine. The previous owner used to keep it outside as well under a tree so I've tried to mimick that environment. I do think it needs maybe a bit more light. So I'm going to move it to a spot that maybe gets a few more hours sunlight. I'll take a picture of it today so everyone can see.
But in other great news.... Our Paph has got a flower on it! Can't wait for it to open!!