Those zones pertain to cold hardiness!!
Not heat tolerance.
It may have a chilling requirement. It may not like your heat or humidity but those zones aren't the reason your seedling is droopy. Just because you don't see them around there doesn't mean it won't grow there. Heavens knows yall don't get real trees down there even if they are native. Speaking of native, Catalpa bignonioides (Southern catalpa) is native to Florida with vouichered specimens in Lake coutny at least. So you should be able to make it work. If your seedling doesn't work out try a mail order tree.

There are two different types coyle if you don't already know.

Northern catalpa (Catalpa speciosa) Hardiness Zones: 4-8
Southern catalpa (Catalpa bignonioides) Hardiness Zones: 5-9

Probably both could grow there but I'm not 100% sure.

I know there are many kinds of catalpa but the northern one has the bigger leaves that I like. Hmm, so the zones are for cold tolerance, that's interesting. I mean sure because it gets in the 90s in Colorado, the only difference would be humidity but more likely it's because they are in pots and up close to my wall where it gets intensely hot; they only droop when getting the sun and then rebound. My Mom was saying that her plants are drooping due to the intense sunlight right now and that it is better to wait until fall to transplant but I just felt in the mood to split them up; mainly because the landscapers have been using their weedwhacker to brush the cut grass off my porch and they might end up whacking one & this way I have a back up; plus I can experiment putting one in more sun and others in less and see how it goes. Oh and quirky- we do get some real trees; my Mom planted a sycamore 25 yrs ago in her front yard and it's like over 75ft now. Who knows, one of these catalpas might end up in the back yard if I can get them going first (messy though.)

We have northern catalpa here in zone 8 part of Texas, as well as the southern. At the end of summer last year, many of them shed their leaves early due to the drought.
They all seem basically healthy this year. I do like the rather unique way they look. Would think the northern would grow where you are, if not try the southern variety.

Maybe it would be best to stick it in a filtered sun location, perhaps even under a patio or somethjing like that until it gets more acclimated to the world. Make sure the soil is not drying out too rapidly.

Zones are for both cold and heat tolerance. Some plants cannot take high summer heat, some need a cool winter to induce dormancy. If there is an upper zone limit (example 5-8), it means the plant will not tolerate the high summer temps or high winter temps of higher zones.

Northern Catalpa may survive hot summers in Florida but it needs to be dormant during winter and that requires cooler temperature than you will have in Florida. Anyway, nothing much lost if you grew them from seed and you never know, it might survive.

It gets colder in the winter than people sometimes think. Right now the ones totally behind the lawn chairs are ok but I put one more in the sun and it was really bad today. Really I wanted them for an ornamental tree in a pot because they look so cool and tropical and in Colorado they are fast growing and extremely hardy. I want to pollard them once they get bigger. I can't believe I am having so much trouble with this tree. I was sure it was going to be the easiest one to grow! I even have to watch out for the landscapers because they might weedwhack them. Makes me kinda protective of them. I really want them to live. There's only 3 really hot months and if they are in the shade they'll be all right (then I'll have to see if that not going dormant is going to affect them. See I gave my Mom a Dwarf Mammoth sunflower variety that was developed just for colorado and they grew totally different down here and I just sent an old girlfried up in CO a plant from down here that's a type of leafy succulent and she says it's growing like a vine up there. Too crazy!

JudyB, this is true The US arboretum devised their zone map on a number of different factors, so what I should have wrote is that the zone map should only be referenced for cold hardiness. There's a million different zone maps out there, the folks that release these plants are more than likely never in Florida and don't actually test them, they just approximate zones. Zone, that will vary from map to map in a place like Tampa, FL where you'll be z 8 one minute and be able to plant blue spruce and sugar maple and the next minute you be zone 10 and can't plant anything.

Plant the right tree in the right place, and examine your own microclimate and conditions. No map can do this for you. The numbers are nothing but a discouragement set forth by people that just don't know and haven't tried it.

Coyle, You might ask in a new post or google around for the northern catalpa minium chill hours. Someone posted a list a long time ago but I didn't save it since I didn't plan on ever needing it.

Northern Catalpa is rated to grow in AHS Heat Zones 1 to 8.
I don't know what city you are located in FL but USDA Cold Hardness zone 9b would be anywhere between AHS Heat Zones 9 to 11 or 121 to 210 days above 86F. Many trees can grow safely about 1 AHS Heat Zone higher then they are rated if they are located in a moist area and it does not come a bad drought. So if you are located in AHS Heat Zones 9 then it could probably grow there if it was kept from drying out and was mulched good and properly etc. If you are located in AHS Heat Zones 10 it might possibly live there in a partly shaded and moist area but the heat would still be very stressful on it and it might could die.

The reason they can grow in CO so easy and well is because there is no location in CO that is above AHS Heat Zones 8 which means there are no locations in CO that have more than 120 days above 86F.

Wow! tell that to my ex, she says the temps are up to 101f this year but I guesss not for 120 days. Yeah, my Mom was saying today that she's had problems with plants that are supposed to hibernate. And she mentioned something about mulch too. Well, I put one under my Hibsiscus and will just see how it does and the other ones I put in the shade behind my lawn chair w' a backing. Actually I am in Southern Tampa Bay, right where it turns into zone 9b so if I keep them in the shade I might be ok. I shouldn't have transplanted them in the summer. I really want these to grow. They are such a cool (though dirty) tree. Thanks!

Your location would be in the upper 10 AHS Heat Zone most years but a few years you might could reach the lower 11 AHS Heat Zone range. So it might possibly live there in a partly shaded well drained moist area. Although it is drought tolerant make sure it does not dry out in the hottest parts of the summer because of the added heat stress they are not used to and also make sure you mulch well after planting with about 4 inches of mulch in a wide area around the tree (not against the trunk). If you cannot grow northern catalpa I'm pretty sure southern catalpa would grow much better there.

The I think if you're going to abide by maps, then the AHS heat zone map is the one to go with. But I still maintain that there is not enough testing and people just guestimate on the zones. Thus they are not a guarantee of success nor failure. If you want to grow a catalpa, then ignore the maps. Be a gardener and try to simulate the best conditions for it as you can.

Well one problem was keeping them against the wall on my porch; it gets hotter there than I knew even though it only gets the morning sun (east facing) so I put them all under my hibiscus tree (also east facing.) There they are shaded under the hibiscus, sitting on ground and not tile, and should be protected from the weedwacking and weedkiller spraying landscapers. I've noticed that they need more water than the ones in Colorado which are VERY drought tolerant. This is all very interesting though about microclimates. Someone was showing me a tree that only grows on these indian mounds because it creates that microclimate being higher up off the ground in an area that is right on the water etc. These catalpas are a nightmare of a tree for upkeep. They're ok for in cities where they just mow and streetsweep all the litter from them but at a residence...I wouldn't want one to get very big and would keep it very cut back (pollarded.) I will be very surprised if such a hardy "weed tree" has to follow parameters like minimum chill days. If so it's done for as we don't get freezes, that's why it's a good agricultural area. I also thought I'd put some nightcrawlers in the soil but they can't live down here either, too hot for them. Well, we ARE getting afternoon showers now so that cools it down a lot. I fertilized them for the first time today so I've done all I can. Thanks for the encouragement!

Wow Coyle! Nightcrawlers? Can you grow nightcrawlers? Can someone tell me if this is true. I lost all the worms on my Catalpa tree so can go with nightcrawlers. Don't know why there are no worms. Had blooms, now have cigars but no caterpillers. Usually would be getting the second generation by now. Nothing.

Novice, the "worms" on the catalpa trees are the larva of a butterfly - I forget which one. The late freeze may have cut the emerging population back. If you google for catalpa worms, you will get more info.

Coyle, if you have the trees in pots, then they need more water more often than if they are in the ground. And moving/repotting trees is stressful, so after dividing them, they would need more water. Drooping leaves in the heat of the day can be a normal action to conserve water - if they are perked up after it cools off, it means little in terms of water needs, but if they are still droopy, then water them. It sounds as though under the hibiscus is better than on the patio for them.

Well, after I moved them off the porch and kept them watered they did pretty good over the summer. In the fall I transplanted them into bigger pots but afterwards they stayed wilted and got that white disease on the leaves so I cut all the leaves off (around thanksgiving) then around xmas I cut the trunks down to about 1 ft. We have had no winter here (70s everyday.) When can I expect some new growth or did I kill them cutting them back like that?

Maybe they are just going through a forced winter rest?

I think drooping leaves are normal, something to do with during the heat and intense sun of the mid afternoon, the plants can't take up water as quickly as they are losing humidity through the leaves. I have a empress tree (paulownia) that's planted in a sunny fenced-in corner and droops every afternoon in summer despite frequent watering.

Another catalpa for you to try is Chinese catalpa, catalpa ovata. It's a smaller sized tree than the northern catalpa, perhaps smaller sized flowers too, but the neat thing is that it blooms in as little as two years from seed. In fact one tree I had started from seed in February (indoors) and it bloomed that same summer.

After blooming the long bean-like seed pods are quite neat looking too, especially in late fall when the tree had lost it's leaves for the season.

Glen (who's experimenting with these trees as well, but from an opposite side of the thermometer).

I just purchased some paulownia seeds and I'm going to put them in the pots with my catalpas (which may be dead now.)
Anyhoo, I'm much more optimistic about the paulownia seeds doing well down here. See, the n. catalpa is not supposed to be able to grow in FL so if it gets new growth this spring I will be very pleasantly suprised. The empress tree is supposed to do well in FL.
I'm just going to keep mine as container trees so that will be interesting to see how they do.
I guess you are pushing the zones with an empress tree in Manitoba. I didn't think they would grow up there very well.

Hi Coyle,

Actually, my empress tree behaves more like a perennial or as some call it, a 'dieback' shrub. Over winter the tree winter kills down to the ground level but resprouts from the base in spring. If you keep the growth to one shoot during the summer, the result is a single trunk with incredibly large leaves. Here mine only reaches about 4 feet high, however, but it may possibly push out more growth per year once it gets more established.

The one downside is, because it only blooms on the previous year's wood and that doesn't survive winter here, there are no blooms, but no messy seeds sprouting everywhere either I suppose.

I've seen the empress tree purposely grown this way (deliberately cut down/stooled/coppiced and allowed to grow to a single stem)in a book about northern plants that can be used, when mixed with actual tropicals, to create a tropical feel garden.

Glen

Oh right, I'd read that up north they might dieback like that, and that it is a desired look because of the larger leaves.

Ha ha ha ha!!! My empress trees are growing like crazy now!

I cut nicks off the top of the still bald catalpas and it's green under there so who knows...I hear they don't come back until May.

Here's the funny: I was telling my Mom today that my plan is to have these container trees then put vines and stuff in them; well she just sees these cut back stalks (and doesn't know what we all know know about this) so she didn't think I was going to have trees in my containers, then she didn't think the empress trees would grow here. HA! From the time I showed them to her to the time we got back from dinner they had grown. She then remarked that I could probably sit right there and watch them grow. Probably. You know what though, out of 200+ seeds, only 7 came up. Luckily. I also planted some okra seeds in there and they sprouted in 24 hours. The containers are full of that $2 a bag cow manure they sell at walmart. Maybe it's even $1 a bag, whatever. I anticipate wild growth this year!
And with the empress trees in a pot I can cut them back ea year right? We are having a good spring here in FL so far.

Are empress trees invasive down there like they are up here?

Why did you not try the Southern Catalpa?

No, not at all. There's not only not ANY around here but out of over 200 seeds I planted only 7 came up at all so...
I didn't go with the southern catalpa because I wanted the larger leaves of the northern variety. What's invasive around here are castor bean trees, brazilian pepper & what I believe to be a mimosa tree (these are going crazy around here.)
Btw, the first empress tree that sprouted is the biggest and growing new leaves daily now, and it's only getting morning sun.
The other thing about the northern catalpa was just to see how it would do down here. I gave my Mom some dwarf mammoth sunflower seeds that were made just for the Boulder area & in FL they grew 6ft+ and had an orange flower instead of the yellow they get up there.

Yep, got the first shoots from where I cut them back before.
So the northern catalpa CAN live in FL, and we didn't even have ANY winter to speak of. I thought they were goners for sure so I started the empress trees, now I've got both :-)