Dendrobium Speciosum

[Petey]

Have had this orchid for may years. I think the last blooming was about 9 years ago. I have repotted twice, fertilized and now and then a new bulb grows out; but no blooming. Is there anything I can do to get some blooms out of this or is it a goner?

[Roberta]

Where in Florida are you located? My suspicion is that it isn't getting enough of a chill in fall/winter, It also needs good light (with just a bit of shading at midday in summer, leaves can toast otherwise). But seasonal temperature variation is the biggie.

These grow well and bloom profusely in coastal southern and central California, outside with very little care. They tend to climb out of pots and that doesn't seem to matter. Along with seasonal chill, they also tend to get cool nights in summer, but I don't know if that is as big a factor.

[Keysguy]

Roberta's questions and points are spot on.

My speciosum is currently in spike down here in the Keys where I get far less of a diurnal temp change than you do assuming you're up on the peninsular somewhere. My guess is yours isn't getting enough light.

In their native habitat in Australia they are typically found growing right out in full sun.

[Petey]

Maybe I should try and give this orchid a change relevant to the sun. It gets its sun in the afternoon for a few hours the way my house is configured. Perhaps I'll put it in tghe east side and get the morning to noon sun. As far as cool weather, we have this season quite a few cooler 9even cold) nights this season but now headed towards spring. Roberta, I live in Palm Beach county. Thanks for all the comments. Perhaps I'll just give it more fertilizer as a boost. Why not>

[Roberta]

If actively growing, maybe some fertilizer. But in general, these Dens don't want much, especially in the cool months. If anything, that could even suppress blooming. Mine get hardly any, and they bloom well. They do want that light though.

Note that Den speciosum is a lithophyte in nature. (Its nickname is "rock lily".) It grows with roots in cracks in the rock to hold on and perhaps find a bit of moisture. Then, it produces "bird's nest" roots, pointed upward, to catch falling detritus from the forest canopy with rain, very little in the way of nutrients. I have seen a Den. speciosum plant in an 8 inch (20 cm) bulb pan, the plant 5 feet (150 cm) across, most of the roots pointed upward. The pot was just to hold the plant for transportation.

[Keysguy]

I cut back on water and eliminate fertilizer completely from Dec 1 until early March. Although we had a very wet winter down here this year so who knows?

[Roberta]

Mine got rained on a lot (at least by California standards) both last year and this year, get watered along with everything else when it doesn't rain. Doesn't seem to faze them.

[estación seca]

It should make multiple new growths every year. Do you water it if it hasn't rained? How often do you fertilize, and at what concentration? Repotting twice in 9 years is probably waiting longer than ideal, but wait to repot until new roots are just forming.

[Petey]

Recently repotted. More than two times in nine years. Fertilize once/mo. Concentration I use the fertilizer suggestions. However, one thing I did a long time ago; that is I cut a few bulbs to start in another pot so I would have two plants. Eventually, original pot died on me. It has 5 mature bulbs and two mini ones. This pot has never bloomed.

[Roberta]

With only 5 mature p-bulbs, it's a bit undersized for blooming (depending on which variety, some are smaller than others). They grow slowly but can become beasts with enough time and with culture that they like.