Leafless Orchids

[Graphicgreg]

Here is a shot of the pile of orchid leaves I swept up this weekend. I also have an album of some of the damage here.
Here in West Palm Beach, we had ten nights with temperatures below 45 F and at least two nights temps reached freezing. We used to cover the shadehouse and put heaters in it (kerosene & propane). But as our collection got smaller from the 04-05 hurricanes that became more work than it was worth. So this year we moved the plants inside, but not all at once. Repots and seedlings near the beginning of the cold spell...choice mature plants midway through...deciduous Dendrobiums and anything else we had room for before the two really cold nights. Some things stayed out the whole ten days. One of those was a Cattleya percivaliana pictured in the album. It took quite a lot of damage which totally surprised me. I have seen its habitat in the Venezuelan Andes and know thatit is one of the highest elevation, most cold-tolerant cattleyas.

I guess it got colder here than we thought

[Ricardo in PR]

A truly blood curdling sight!

[epiphyte]

Thanks for documenting the cold tolerance. Here are some of my thoughts when I looked through your gallery...

The phals...no surprise
Grammatophyllum scriptum...looks better than I would have expected. A couple times I've been tempted to purchase a Grammatophyllum but most, if not all, are tropical lowland species (TLS) and so far this is the first reference I've run across to their cold tolerance level. I'm curious how an Ansellia africana would have fared in the same situation.
Epidendrum stamfordianum...not surprised that it doesn't look that bad
Dendrobium smillieae...seems to fall into the category of typical TLS
Dendrobium farmeri...looks like it should recover quickly. Mine has no problem down to 33F.
Caularthron bicornutum...was hoping this one would be an atypical TLS (ATLS) like the Myrmecophilas. Are the photos of two different plants or of the same plant at two different stages?

In the Miltonia flavescens in Snow thread we broached the topic of outdoor orchids in Florida versus Southern California and in the Minimum Temperature Errors thread there was discussion on the relevance of minimum temperatures. The orchids outdoors in Florida that manage to survive the minimum temperatures are more than compensated by the higher average temperatures.

Maybe the basic equation (with somewhat arbitrary numbers) would look something like this...

Minimum Temperatures (mt)
Average Temperatures (at)
Growth Gain (gg)

Southern California...
6at - 2mt = 4gg

Florida...
12at - 4mt = 8gg

If you're interested...next time you purchase some relatively inexpensive seedlings of species from Oakhill or somewhere else let me know and perhaps we can see if it's feasible to sufficiently minimize the influence of the other variables (fertilizer, water, medium) to come up with some useful, somewhat more scientific, conclusions.

[fotofashion]

How sad to see. You say your temps got to 45 and you got all that damage? The temp in my GH got to 32 one night and 34 another but nothing was damaged at all, not even my phals. I have a B. medusae in bud and it is OK. Just found a Dend. Aussie Chip putting out 8 spikes.
I sure hope something survived for you.
Beverly A.

[Pantoufle]

Oh Greg, Sorry about your plants. I have had a few Cattleyas growing in trees for about seven years but this year it was too cold for too long in southern Louisiana. They are now masses of mush. They were nice but nothing special. It was an experiment. What I was really surprised about were the Doritaenopsis hybrids and Doritis species in the greenhouse. I have the heater set for 55 degrees F but I lost many leaves on the species and some hybrids lost every leaf. I plan to raise the setting to 65 degrees F if we are forecasted to get freezing temperatures in the future because the plants near the walls were the ones that suffered the most. It must have been much colder than 55 near the walls. I didn't have problems with any other plants. When I saw the damaged plants, I thought, our orchid growers in northern states really have to be admired for persevering through their long harsh winters.

[Marci in SoFL]

Ouch! That's hard to look at, Greg. We hauled almost everything inside. A B nodosa and a huge Schom too large to move indoors appear to be fine. Our deciduous Dens that were left out don't seem to be damaged but I'm still holding my breath, as leaves from a few large catts and phal-type Dens we hoped would be okay are dropping daily.

[Kathy-WPalmBeach]

Here in West Palm Beach, we had ten nights with temperatures below 45 F and at least two nights temps reached freezing.

What was bad was the 10 consecutive nights BELOW 45 degrees at the end of which, the last 2 nights reached 32 degrees. We also have had no problems with 45 degrees - especially if the days warmed up somewhat. But during this cold spell, there was no let up and 45 degrees was the warmest it got at night and the days were mostly cloudy and blustery.

[EdM-in-TN]

Ouch, Greg & Kathy, those photos are painful.

Send Carlos the bill for his education.

[Graphicgreg]

It is sad...especially the Dendrobiums. We have a large Den. junceum, Den. crumenatum and one of the two big Den. purpureums that all look a goner unless there are some hidden leads that were protected. And even then it would take years for them to come back. What DID surprise me was the damage some of the deciduous Dendrobiums took...especially Den. smillieae. There have been many years when these plants have tolerated 35 F without any ill signs. Once the leaves are gone the plants are quite cold tolerant. Not this year though.

[Kentucky]

Thanks for the pictures, Greg. Sorry you had to run this unintended experiment.