Hardiest epiphytic orchid?

[plantzzzzz]

I feel like Neofinetia falcata or maybe some dendrobiums are probably up there, but I'm wondering if anyone knows of others?

I know that the dream of having a tree outdoors, covered in ferns and orchids isn't possible here in Toronto, but maybe it's possible in Vancouver or something?

[rbarata]

The hardest for me are those that require environmental conditions I can't provide...epiphytic or not.

[Roberta]

I think you would have a difficult time growing any epiphytic orchids outside in winter that far north. Even in coastal Vancouver, there is significant frost. Some of the more durable epiphytic species, such as Laelia anceps, can handle slight frost if followed by warming during the day. But even those need the ability to move to protected areas if it gets colder than around 29 deg. F (-2 or -3 deg C) If they are on a tree that would be a major problem! (Remember, it's the extremes that are a concern, averages are not useful in figuring what you can get away with)

Note that epiphytic species don't occur naturally in North America north of Florida or maybe a little more. On the other hand, you can grow terrestrial orchids that are impossible for those of us in frost-free areas and there are some wonderful species. We all like to push the envelope, but there are limits...

[Optimist]

Have you considered Cypripedium? I think they are gorgeous; Cypripedium parviflorum (Yellow Lady’s Slipper) and Cypripedium reginae (Queen
Lady’s Slipper).

[Fernando]

Nope. Not because of tº alone, but because of coincidence of low tº and rain/humidity.

[MrHappyRotter]

As others have mentioned, it's probably a pipe dream to expect any epiphytic orchids to survive long term in your area, but to answer the question (as best I know), some of the hardiest tropical epiphytes would be ...

1. Nobile type Dendrobiums - This would be highly dependent on the species (or hybrid), but I know for a fact I left my plant out this past winter in a protected spot (and no water) when night temperatures dipped down into the upper 20F (-6/-7C) range with no apparent harm.

2. Epidendrum magnoliae - A Southeastern USA native that has been reported to be able to survive in protected areas outdoors in temperatures in the upper 20F (-6/-7C) range. Similarly, some of the recent hybrids involving other cool/cold tolerant species might be able to match cold hardiness. This might be able to cope with damp winter conditions, but I wouldn't push it.

3. Epidendrum nocturnum - This wide ranging species is known to occur in Florida (and possibly other parts of the US). Plants bred from parents that were originally from the USA will probably be more cold hardy. I got one of these that ended up being a clone that doesn't open its flowers so I sacrificed it to mother nature. It survived several frosts/freezes before it kicked the bucket, and that was likely due to the abundant rain more so than the temperatures alone.

4. Encyclia tampensis - Another Florida native that has proven to be "frost tolerant" if sufficiently protected.

5. Brassia caudatum - This one is a wide spread species, said to occur in very limited areas in Florida. Most clones available in cultivation are likely not from North American populations, and I haven't read much about actual cold hardiness, so this is mostly a guess based on the fact that it grows wild in Florida.

Keep in mind, as others have already pointed out, that temperature is just part of the equation. These plants all seem to be able to handle cold temperatures if and only if they remain dry during cold weather. Also, they have adapted to tolerate short periods of frost/freezing (typically for a few hours over night), so they aren't likely to handle freezing temps for weeks on end, day and night, or even just all night long. You'd also need to experiment with lots of each plant since cold hardiness will vary from clone to clone. So, if you had a couple dozen Epidendrum magnoliae, you might find that after a few years, if any at all survive, it may only be 1 or 2 specific clones that happened to be placed in just the right spot.

[Orchid Whisperer]

Epidendrum magnoliae (green fly orchid) is epiphytic and native on the east coast of the USA to Columbus County, North Carolina (record cold 12 F, not sure if it is hardy that cold). It is not a bad little green orchid, but not exactly breathtaking.

[Subrosa]

I had a small division of Coelogyne Unchained Melody accidentally survive a zone 7 winter outdoors, under an overhang where it remained dry. It wasn't the coldest winter, and the plant was right up against a south facing foundation wall covered in leaves, but temps did drop into single digits.

[mremensnyder]

I would conclude from previous knowledge, and some of the above responses that the answer is: Epidendrum magnoliae in the Western Hemisphere and Neofinitia falcata in the Eastern Hemisphere. Which is more cold hardy between these two? I'm not certain, but I suspect it's Epidendrum magnoliae. I don't recall reading that Neofinetia falcata can survive temperatures in the teens, while Epidendrum magnoliae would undoubtedly have to be able to in some of its northernmost range (even if it would not survive 12F, it would certainly have to be able to survive 15F-20F in North Florida and up to the Carolinas, despite being tucked away in sheltered forests).

I will say though, there are quite a number of epiphytic orchids native to Southern Japan and Subtropical China. Maybe there are some little known species here which would be as or even hardier.

It is just not in the physiology of the epiphytic orchid to be able to withstand hard freezes (and certainly most cannot survive freezing at all).

An interesting side note about super cold hardy epiphytes. The resurrection fern, the range of which generally corresponds with the boundaries of the subtropics in the Eastern Unites States, can be found in the wild as far north as New York and Pennaylvania.

---------- Post added at 01:10 AM ---------- Previous post was at 12:53 AM ----------

I had been growing a specimen of Paphiopedilum druryi in the Orlando area for 20 years and I can state for a fact that it can handle frost and light freezes to the upper 20s. I pushed it a bit by leaving it completely unprotected during January 2010, when many nights were below freezing and at least 2 nights reached the mid 20s, lowest was 24F. That period featured a lot of wet cold as well and a period of sleet one morning. My Paphiopedilum druryi, which by then was a large clump in a sizable terra cotta pot, lost about 2/3 of its total mass but survived and took off to recovering the next spring. This species is quite cold hardy and I am sure it is not the only Paph that is.

Regarding Brassia caudata, I remember reading a source which stated that it is one of the truly tropical orchid species that has just barely managed to gain a foothold in the most sheltered forests of extreme South Florida. I would not expect it to show any freeze tolerance.

[mremensnyder]

In searching orchid listings on eBay, I came across an orchid species that I thought looked interesting. When I am not familiar with a species, I always look it up on orchidspecies.com to get some basic information. The species is Pelatantheria scolopendrifolia. According to orchidspecies.com, this epiphytic orchid species is native to Korea(!), as well as parts of Japan and Eastern China. This may be a contender for the hardiest epiphytic orchid, as I am not aware of Korea having any subtropical, let alone tropical zones.

Follow-up, apparently Korea does have areas classified as "humid subtropical", but by this same classification system, New York City and Washington DC are considered to have humid subtropical climates. So, does South Korea have any areas that remain mostly or completely frost free year-round (the type of climate needed to support any epiphytic orchid species I am aware of), or is Pelatantheria scolopendrifolia in a class all its own in terms of cold hardiness for epiphytic orchids?