Place the seeds in slightly damp peat or soil, place in the fridge for 30-45 days (stratification). then bring out into the warmth. Catalpa grows fast! It is a virtual weed in my garden.

Yes, i know they grow fast ⺠So far, I haven't had any that have grown on their own.

When we moved into this house, we had an Ailanthus altissima in the backyard. i can't believe anything could be more weedy than that!

Thank you for the information.

On another note, we have Catalpa sp(?) growing here in the north country in z4a(almost z3b) above the 45th parallel.
These seem to be very hardy and I wonder if this is unusual.

I would have no idea! Below is a link to the USDA Database. It shows Catalpa Speciosa growing in MN. Whether or not it's indigenous there, the site didn't say. Sorry I couldn't be more helpful.

Here is a link that might be useful: USDA site

If the USDA website has a map like the one referred to, at the bottom left corner is "native status". If you click on it the map changes color and by the shading you can tell if it is native to your area. In this case Catalpa is native to the Canadian border. Probably native along the border area but not shown on map.

I did this, quite by chance, two years ago. I laid the long pod( from a neighbour's tree) in a window box, out on my porch in the spring.
I thought if I were lucky, I might get 6 or 7 plants.
Instead, I had more than a HUNDRED spring up a month later!
Too close together to effectively separate.
But somehow I managed this, and now I have 10 or 11 in large pots, that I bring indoors late every fall. I gotta sell 'em soon! I DO NOT NEED this many catalpas!
And oh, yes - the rest I planted in a big bunch in my back yard. Last spring they mostly all started growing also!
I never realized they were such a weed - even in Canada.
Generally outdoors (I'm in Southern Quebec) they do not start leafing out until late May, and flower towards the end of June, or early July.
So, in May, do not think your tree has died. Wait a while.

In point of fact, while I find the USDA pages to be a marvelous tool, they're not necessarily 100% accurate. Then there's the gray areas: N. catalpa may be native to MN all the way to the Canadian border, but in reality, it would never be found in the north of that state or neighboring WI on its own. Simply wouldn't happen.

None of which should be taken to mean it's an innapropriate choice for the landscape. I rather like them used as street trees in my community. We're just south of Green Bay, and already here, nature would not have distributed this species in any meaningful numbers this far north.

+oM