Oeceoclades calcarata care

[MateoinLosAngeles]

Any tips on Oeceoclades calcarata?

I understand this orchid is mostly a lithophyte growing in between alkaline rocks rich in Calcium and Magnesium. I have it potted in a terracotta pot with equal amounts of coco coir, perlite, orchiata "precision" (the tiniest size), and small lava rocks (black, red, zeolite, and maifanitum)

I've seen some contradictory advice in terms of light and watering. Some online info suggests treating it like a succulent, while others recommend Phalaenopsis light (800-1000 FC). Regarding watering, some mention water often, others to water sparingly. I also have read a lot of suggestions mentioning that this plant can basically take anything.

I couldn't find a sheet from the Baker's on this orchid. Based on this website: Specimen - Oeceoclades calcarata (Schltr.) Garay & P.Taylor I see it grows and has been photographed near Ambatofinandrahana in Madagascar, on rocky surfaces and higher elevations. This area is extremely wet and muggy for about half of the year, the other half it experiences a "drier" season with occasional rains (the lowest is twice a month in August) and when humidity plummets for a couple of months. Yet, I haven't read anything about Oeceoclades calcarata needing a dry rest period.

Regarding light, this orchid seems to grow high up in the mountains on open rocky fields that lack a canopy, growing in between rocks. It makes a lot of sense that this is a cool-temperate growing orchid, but in terms of light, this habitat suggests more of a Cattleya or Odontoglossum light to me, than a Phalaenopsis light.

So far I've kept my plant on a NW facing window where it gets some direct sun for about an hour or two in the afternoon. I've been watching it like a hawk but there are no signs of burning whatsoever, which makes me think this plant can really take a lot...

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I've been there but didn't see it. The habitat description is exactly where you find Pachypodium brevicaule, which I did see. There is some water below the surface all year, even during dry periods, because nights are cool all year. So they don't need a dry period. Days are pretty hot even in winter, but it can dip to freezing. The plants snuggled in the rocks don't get quite that cold. Their roots extend down into rocky, sandy soil. They are surrounded by grass during wet seasons so they don't really get full sun. They do need very bright light, though.

Keep in mind plants grow where they grow not because they like it there, but because they can outcompete other plants there. It's rare a plant in a genus needs a special substrate different from its relatives.

Succulent growers treat this like any other succulent. They tend to underwater "succulent" orchids because that's how they're trained. I don't have it because it died in Phoenix heat.

I keep my other Oeceoclades and Eulophias moist to wet all spring and summer, and reduce but don't withhold water in fall. A loose Cymbidium mix works well for larger plants. Most Oeceoclades are small to miniature shade plants, but not this one. Most of the little ones grow in leaf litter lying on top of rocks, like many Paphs. They're on the forest floor but not really terrestrial because their roots don't enter soil.

[Roberta]

There are two photos in Orchidwiz that appear to have been taken, not quite in-situ since there is a potted plant nearby, but planted in what looks like sandy, rocky soil with not much around it (so likely getting bright light) So that looks to me like it's being treated like a succulent. Definitely not being pampered. Based on the habitat description in IOSPE, it experiences desert-like conditions at least some of the time. Also looking at synonyms, it's related to Eulophia. Based on these little hints, I would put this into the "takes anything" category. Neat plant!!

From what I have observed with the Eulophias that I grow (and what I know of desert plants generally) they're opportunists... they tolerate dryness, but if they get water, they grab it and grow.

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Coming back after looking up something... Grigsby Cactus in Vista, California has sold this for a long time under the name Eulophia paniculata. That's where I got mine. They sell other relatives. The late David Grigsby was an excellent propagator. Many succulents from Madagscar were sent first to him for distribution.

[MateoinLosAngeles]

Thank you both. I'll still watch it like a hawk, especially during summer, but I think it can live on this NW exposure without too much fuss. Looking around the forum I've seen another grower mention he puts his under light that could burn a Vanda.

As for watering, I follow the "water often and abundantly" principle for all my orchids and adjust media and pot size to ensure those that can't tolerate dryness stay moist between waterings. So I'm just going to follow that same principle with this one.

I have been letting it dry out more than I would've, say, a Cattleya. But, I think from now on, I will water the heck out of it, especially during Summer, and see what happens. As you say, Roberta, it'll potentially take as much as it's given, it definitely has the big fat pseudobulbs to store it.

Regarding potting media, I didn't initially know that this was in the Cymbidium and Eulophia vicinity, so when I got it, I mixed and matched the media based on what I could find about its habitat. No other reason.

Wouldn't like to lose it because it's a rare find, but I only paid $12 for it, so the loss would be the nuisance of finding another one, not really because this one was expensive. Maybe I'll report at the end of the summer, or the year, on what worked and what didn't.

Wish the camera would capture the silver hue of the leaves—quite a cool plant.