You should expect occasional below freezing temperatures in Houston and even an occasional ice storm. When I lived in Houston many years ago I would move my orchids into a small greenhouse in the winter.

Oh I see! I am still learning a lot about the names!! I would really appreciate your advice Roberta! :D
What would you suggest for these three?

1. Hisako Song ‘Mama Mia’
On orchid roots, its parents are ‘Rhyncholaeliocattleya Hisako Akatsuka’ and ‘Cattleya Mini Song’.

2. Lc. Orglade’s Grand ‘Yow Chang Beauty’
It’s parents are ‘Cattleya Mildred Rives’, and ‘Cattleya Persepolis’

3. Rlc. Mahina Yahiro (White)
Parents are ‘Rlc. Meditation’ and ‘Rlc. Donna Kimura’

These are my favorite ones I have so far..I really want to get them to bloom!!

---------- Post added at 02:52 PM ---------- Previous post was at 02:50 PM ----------

We have had some strong sudden freezes the last few years. I will have to take proper precautions.

---------- Post added at 03:04 PM ---------- Previous post was at 02:52 PM ----------

Very interesting! There is a lot to consider here. Thank you!!

Rlc (Pot.) Hisako Song - a very complex hybrid, not going to list all the constituents, but enough of it (40%) are cooler-growing species that I'd call it "marginal". Below around 50 deg. F, I'd protect it. This one likely a candidate for a windowsill or greenhouse.

C ( Lc.) Orglade's Grand - Both parents are classics. If you dig down to the species level, you have 16% warscewiczii and 13% dowiana, so nearly 30% warm-growers. the you also have 31% mossiae and 20% trianae, which are "sort of" forgiving. If temps are much below 50 F, I'd bring it in.

Rlc (Blc) Mahina Yahiro - Fairly similar composition to the rpevious. Slightly higher percentages mossiae and trianiae, but given the complexity of the hybrid (and its long pedigree of classics) I'd also manage the same as above.

If these are typical if your collection, I'd use 50 deg. F as your cutoff. And the additional cautionary note from Hunhunt says "don't take a chance". Don't move your plants back and forth, find a place where you can manage them for the winter. If you don't have a greenhouse and need to bring them into the house, consider getting some supplemental light for them. House temperatures will be fine, Catts aren't particularly sensitive to humidity, but they do need good light (as well as nighttime darkness) to bloom.

Time to start planning!

Using orchidroots.com to determine ancestory:

Rlc Hisako Song has a whole laundry list of cattleya alliance ancestors but number 1 on the list at 18.71% is C. dowiana.

Lc. Orglade’s Grand has C. dowiana as an ancestor at 13.27%.

Rlc. Mahina Yahiro has C. dowiana as an ancestor at 17.96%.

Hard to say if that percent contribution of a warm growing cattleya will have much impact on cold tolerance but it is there to consider.

---------- Post added at 02:44 PM ---------- Previous post was at 02:41 PM ----------

Sorry, looks like Roberta already responded thoroughly to your question while I was preparing a response.

Hunhunt, glad you pointed out the benefits of Orchidroots - which is free and available on the Web to everyone. OW takes the analysis a bit farter, but it is 1. expensive and 2. being retired - still available but won't be updated.

It's easier (and more accurate) to use the characteristics of ancestors on primary hybrids or maybe 1 or 2 more generations from the species. But for very complex hybrids like these (with long pedigrees) the envelope-pushing doesn't work so well. Best to be on the cautious side. Add to that the danger of "real cold"... zone 9a is very different than 10 a... I agree that outdoor growing in the winter, even for very tolerant orchids, likely isn't a very good idea!

Wow!!!! This is eye opening. Okay, I do have a lot to think about. I agree, I need to keep them somewhere stable instead of moving them back and forth. Just sounds like a recipe for an accident..I will have to move them indoors with supplemental light as you suggested. Because I don't have a greenhouse yet! It can get seriously cold here sometimes, and I don't want to take a risk.
I have an indoor orchid room for my phals that will be good for them, I'll just have to get much more light in the room!! Your help is greatly appreciated!!! Thanks tons.
Now I will have to do research the rest of my collection as well..lots to see and learn! :blushing:

Not many orchids will tolerate hard frost, Even the very tough ones, like Cymbidiums (most of them) , or Laelia anceps, can take only down to about 28 deg F, for a few hours, (assuming they can warm up during the day) without damage.

Interesting. I am so glad you told me now! :D
Also side note, I am in love with cymbidiums. I see that you grow so many. I hope I can grow some one day! ..maybe indoors? Fingers crossed haha!!

You can grow Cyms outdoors most of the time. Need to bring them in when it gets REALLY cold. Here's what one commercial grower did to manage serious cold... utilizing the fact that as long as there is liquid water, while ice is forming the temperature does not go below 32 deg F.
Ice
Citrus growers do the same thing - low-flow sprinklers that keep liquid water present, as it freezes. Obviously too complex for a small home collection, bur when it's your livelihood on the line, you get creative.

Omg!!!! Awesome!!!! Science is so cool. I can't believe how untouched those blooms were after a freeze like that. I will have to get some cymbidiums before the year is up..
Why do you say citrus growers in particular do this as well? I have a lemon tree..Have been working hard on it all year..I think I may bring it in the garage when we get our first freeze.