The mysterious hardiness zone of "who woulda thunk it?"

Sometimes I think USDA hardiness zones are like the twilight zone. Unless you experiment, you might never know if something will really work where you live, because everyone who supposedly knows, says it won't. I call that the hardiness zone of "Who woulda thunk it?"

Dumb name, I know. But, who would have thought that this very tropical Calathea ornata would freeze to the ground in a hard 20F freeze, and then...COME BACK? In zone 8B? BTW these leaves are emerging at a size of about 10" long. Not teensy tiny.

And I know I posted before about my white Tacca that did the same thing. It was simply frozen to nothingness, and now, it has leaves over 2 ft. Who woulda thunk it?

Another WWTI...
Zingiber collinsii Silver Streaks. Nothing new about Zingibers being hardy in this zone, but to be honest, when I first planted this out about 4-5 years ago, I was darn scared. It was hard to get a pricey then (probably still is as far as I know) and I was really scared to lose it. So I only planted one piece out. But...totally hardy here!

And another kind of WWTI, but a WWTI nevertheless...

Costus stenophyllus. I used to grow this in the greenhouse, where it was a huge plant, 12-15 ft tall canes and bloomed profusely. But it was trying to take over (like those darn torch gingers) so I decided to remove it and keep a containerized specimen.

I was keeping it for foliage, because, by ALL accounts, no one had ever gotten it to bloom in a container before (except me, ONCE, years ago, and I only got one bloom and because I failed to get a photo no one would believe me they thought I was making it up) but I am happy to say, history HAS repeated itself and I currently have a bloom on one of my containers of C. stenophyllus!! And I think another is developing!! I got the pic this like.

"I consider every plant hardy until I have killed it myself...at least three times" - Tony Avent. Aechmea recurvata in zone 9A.

Yeah I have Se. recurvata in the flowerbeds here too, its a great performer. So are Ae comata and most of the Dyckias

I've got one of those Calathea ornatas, it's the only Calathea I've had success with. The others have just faded away, don't know why. It gets less water in its position than the others did where they were.

I found out that several tropical plants are hardy (semi-hardy) in the Atlanta area. I left the following out in pots over winter. We had one week where we close to single digits over night (10 - 12 Deg). This past winter was one of our coldest in the last several years. We have several weeks of overnight temps in the low 20's.

Rabbit's foot (Davallia fejeensis) fern in a coir lined basket on flagstone - completely hardy. PF has it has a zone 10 plant?
Most cordylines have come back - albeit slowly.
Bird of Paradise (Strelitzia reginae) has shown several leaves emerging from the ground - all the exposed leaves are brown and dead.
Brazilian Glory Bush/Princess Flower (Tibouchina semidecandra) is coming back.
Variegated Shell Ginger (Alpinia zerumbet 'Variegata') has a few new leaves.

Variegated Shell Ginger, Tibouchina, Cordyline and Strelitzia are all able to come back here without any problem, but never the Ti never gets as big as it was before.

I also have Alocasia Stingray and Alocasia lauterbachiana coming back, I wasn't certain either were going to be hardy here.

ALocasias "Polly", "Purple Prince", loweii and grandis also come back here which was a surprise but I have had them return for about 4 years, as well as Monstera deliciosa

Well, after reading all of that I just have to include my
little 2c if it is okay..........

I am in Cenral Alabama and the zone can vary 7b-8a...but
some of these were just mistakes in the rush of loading the greenhouse
because it was simply going to freeze....

I left out a Norfolk Island Pine, unknowingly there was an Alocasia amazonica
in that same pot (go figure), walking iris, galangal, turmeric curcumin, and a
rabbits foot fern. These are the least..........I am sure there have been more.

I never let them stay out another winter though. All are thriving.
Oh, almost forgot the Alocasia frydek....but it's pretty tough anyway.

Allison, I have to say... Frydek is among the hardest of alocasias for me.
I have been growing it for years...at least 10 years. And I can't ever seem to please it. Ihave the regular green one, the albo-variegated one, and the aureo-variegated one. They come and go as they please.

I have learned with some of the more 'unusual' alocasias....they have a definite schedule of basic existence that does not seem to actually coincide with my own schedule of how I think my plants should be growing. They grow, disappear, and reappear at will. I used to think I had actually killed them. Then, I realized...they were operating on an entirely different schedule or existence than I was.

I just had an Alocasia Imperialis reappear after 2 years of dormancy. I had it growing in a cocofiber basket. When it 'went away', I knew better than to discard it. I stuck it in a corner of the greenhouse and ignored it. And now its emerging again, beautiful, simply gorgeous. My Alocasia 'Nishihara" and 'Tigrina'

All things have their own timetables. They may not be OUR timetables, but they exist. I believe its that way with cold too. Things may not actually DIE. They may just go to sleep, and wait for better times to re-emerge. I never throw anything out until its been fallow for about 4 years.

Calathea louisea has been very hardy here in Zone 8 for decades. Will definitely have to try C ornata now! Z collinsii has a natural dormancy and is why it does well unlike Z midnight that is an evergreen that hates cold despite what many sellers say.

Tim Chapman