rupicolous laelias - Types of rock

[rbarata]

Anyone knows what's the best type of rock, in particular those species that have the Sierra Madro Oriental as habitat?
There's a lot of information available, too much information so it's difficult to filter what's important.

Thank you

[bethmarie]

Do you grow in a greenhouse, under lights, or something else?
Rupics are rock growing in their habitat, but that doesn't always translate so well into pot culture.
I grow indoors under lights, and I lost many little laelias planted in rock-- root by root, from under watering.
In my growing space, mine do well in small bark (if few roots, I put a styrofoam peanut or a layer or two of aliflor in the bottom of the pot), in 2.5" plastic pots, that get watered about every 5 days currently. When they are actively growing again, I may have to water a little more often.
Pictures show the trials and tribulations of a lucasiana that endured and survived my learning curve. Those psuedobulbs in back? They were fat and happy when I got the plant not that long ago (in rock), and they shriveled dramatically while I learned. The most recent growth is still a bit under watered, but it's rooting well and in bud right now.
Last picture shows rupicolous laelia, in situ. ;-)

[Roberta]

Remember that these plants don't grow strictly on rocks, but rather, they root into crevices where they find moisture and a bit of organic matter. They may also then spread roots onto the rock surface, but that's not where they start.

I have had good luck using the following potting style: First, put a layer of gravel at the bottom of the pot (I use terracotta pots). At this point you can put the plant into the pot. Add a thin layer of sphagnum (to hold the soil) , then, a layer of potting soil (about 1/2 inch/1 cm). Then fill the rest of the pot with gravel.

I grow them in full sun (40% shade cloth, summer bright sun duration is 12-13 hours) outside in coastal southern California. They experience summer highs of over 90 deg F (32 deg C) or more, and winter nighttime lows occasionally down to 35 deg F (3 deg C) or even a little lower. Basically, Cymbidium conditions for temperature and light are pretty close, Rupis perhaps a little brighter.

[estación seca]

The rock domes you see in photos of Laelias growing in Brazil are almost always granite. The underlying granite is often white or pale tan. It appears black because it is covered with a layer of cyanobacteria, also known as blue-green algae. It should be very easy to walk up these bare granite domes, even when wet, because fractured and weathered granite is very rough, providing substantial traction underfoot. But these domes are exceptionally treacherous when wet. The blue-green algal layer becomes extremely slippery. Walking up one of these requires full attention and careful foot placement. These domes in Brazil tend to get more water than similar formations in other parts of the world.

Cyanobacteria are able to convert molecular nitrogen from the atmosphere to compounds plants can use, and a great many plants in water-restricted environments seem to grow in association with them.

Dead leaves and dust accumulate on irregularities on these granite domes. Moss grows on this detritus. This forms mats only a few centimeters thick, which remain moist long after it has rained. The mats may extend in all directions for many meters; on steeper slopes they are more restricted.

Lithophytic orchids root into these mats of dust, organic matter and moss, and are not exposed to the air and sun. The only place you typically see roots are at the very bases of plants. In this way they are protected from the high temperatures of sun on bare rock in the tropics. Jumellea in Madagascar grow in similar situations.

Some Laelia sp I saw (no flowers, no ID) near Diamantina in Minas Gerais grew on igneous intrusions into what had been metamorphic rock. The metamorphic rock had eroded down to form fine white quartzite sand. The intrusions were flat-topped benches about 25cm / 10" above the sand. The orchids grew on top of the benches, with their roots in sand. During the summer rainy season there would also have been a lot of annual grasses growing on the benches, shading the orchids. This spot is mostly desert, and receives little rain. The fine white sand would retain water far longer than bare rock. In winter night temperatures can dip to just below freezing, and the Laelias were completely exposed to the sky.

The main lessons I drew from these observations are that rupicolous Laelias in habitat have access to much more summer water and nitrogen than people unfamiliar with how they grow might imagine. The primary hybrids I have from Sunset Valley Orchids are extremely thirsty plants during the summer, and I think the advice to water these sparingly is completely incorrect. They need high air availability at the roots, but also a lot of summer water while pushing new growth. When I upped my watering the plants began leaping ahead. My 2 are in medium bark in plastic pots. If I had time to water them every day in summer while they make new growths they would appreciate it. They do suck all the water out of the pot that rapidly.

[rbarata]

Thank you for the replies...I'll explain my project...

It all begins with this... a clay rectangular pot (what's the english term for it?)...



... and this... a Laelia anceps...



My project is to put it growing outdoors in rock.
Following Roberta's idea I could put the plastic pot directly inside the medium in the clay pot, or wait to repot it next fall. I haven't decided yet.
So the idea is to let the rhizome grow freely outside the pot and let the new roots grow into the medium (again, outside the plastic pot).
That's when I thought...why not put medium/large size rocks, broke them to create cracks and fill them with debris?
Considering the water availability in summer mentioned by ES, I could place the rock laying over some type of good water retention medium such as bark+sphagnum so that the new roots can have the possibility to go under the rocks if they want.
With this design I think new roots will have at least three different ways to choose: directly on the rock, into the cracks or into the cracks and under the rocks.

What do you think about this?
I know anceps is not a true rupiculous Laelia but i the wild they can be found growing like this.

[estación seca]

That's a trough.

Don't! Laelia anceps is a true Laelia, from Mexico. It is only distantly related to Brazilian Laelias, now Cattleyas. It grows on evergreen oak trees at higher altitudes. As such it is under a loose canopy throughout the year, and does not get strong sun during hot times of the year. Brazilian Laelias in habitat get much hotter and stronger sun through the year than most Mexican Laelias.

Hot for L. anceps in the summer in habitat might be 35C / 95 F. Hot for Brazilian Laelias in summer might be 50C / 122 F or higher.

L. anceps roots dry out completely between rains, and are always fully exposed to the air on the oak branches. Brazilian Laelias have roots under moss and detritus, and they stay moist to wet longer.

I would be surprised if L. anceps ever grew as a lithophyte, except in rare circumstances of rocks shaded by trees.

I think your experiment might work for a real Brazilian Laelia, but it's not a good idea for a true, Mexican Laelia.

I recall you writing Brazilian Laelias aren't available in the EU. Maybe some of the vendors who import Catasetums from Fred Clarke at Sunset Valley Orchids might consider also importing some of Fred's Brazilian Laelia primary hybrids? He has recently released plants for sale that are fully Brazilian Laelia, hybrids of primary hybrids he mostly made.

[Roberta]

English term is "clay rectangular pot" too...

thought we were talking about rupiculous Laelias. L. anceps isn't, it's definitey an epiphyte.

I think just put the plant, in its pot, into the clay pot, add enough rocks to stabilize it. I would suggest then putting some large bark on top of the rocks, to give the plant a little organic matter and some moisture for the roots to be attracted to. Then your plan to just let it grow out of its existing pot makes sense to me (rather than risk disturbing roots) But rocks alone will probably not do what you want unless you water a lot more that I think you want to.

[rbarata]

I can find some Brazilian Laelias, and I probably wrote about the difficulty of finding an adult Sophronitis mantiqueirae, but as this anceps growing pattern makes it a perfect candidate for a rectangular clay pot () and the fact that they, sometimes, grow on rocks I thought about this project.

I think I'll stick to the original idea as Roberta described.

[Orchid664]

After being unsuccessful growing rupi's in rocks (under lights), Fred Clarke from Sunset Valley Orchids suggested clay pots with a collar of sphagnum moss, leaving the bottom half of the pot empty. My rupi's have never grown or bloomed better.

[rbarata]

Originally Posted by Orchid664

...clay pots with a collar of sphagnum moss, leaving the bottom half of the pot empty. My rupi's have never grown or bloomed better.

I'm not sure if I understand what you said...can you elaborate?