Bonsai Possibility? Best time to uproot?

[dstahre]

Hello!
I've had a tough beginning to the year, which will result in me selling the house I've lived in for 35 years. There is a very old White Ash here that's monstrously tall, taller than my house, even! I'm looking for a way to take a piece with me. I'm afraid the next owner may cut it down.
I thought about getting a cutting of it and some root hormone and growing another tree, but then I saw a seedling under the porch yesterday! It's about 8" tall, and almost looks like a single compound leaf sticking in the ground.
I'm now thinking that bonsai might be the way to go with this, I'll be able to keep it on my porch or in my house, instead of planting it in the new place, which may not be possible.
All of that to ask, when is a good time to dig up this tiny tree?

 

[R0b]

Assuming north hemisphere based on species. Now is a good time, protect from frost though after digging up. Plant it in a container and let it recover for at least a year before deciding what to do.

I hope things turn around for you.

 

[dstahre]

Assuming north hemisphere based on species. Now is a good time, protect from frost though after digging up. Plant it in a container and let it recover for at least a year before deciding what to do.

I hope things turn around for you.

Hi! Yes, Northern hemisphere. I should've mentioned location, mid-Atlantic US.

Sounds good. I've got a few empty containers now. I'll pick up some soil and get it potted!

And thank you!

 

[penumbra]

Dig it now.
A few points. Ash make terrible bonsai if bonsaiable at all. It has to be kept outside all the time. Seedling is your only option, you can't root it. I am not sure of your location but you should be aware that all the ash are dying. A small plant in a pot will probably not attract the attention of the Emerald Ash Borer. Otherwise they are very tough plants and you stand a good chance of keeping one alive if you monitor it frequently, learn about it and give it what it needs.