Any ideas?

I found this growing in the garden ages ago potted it up and now it's quite big(about 3ft) anyone know what it is?

 

Looks like an Accacia of some kind

 

I thought that!

Is there an acacia growing anywhere near?

Tuck it away out of the frost for the winter.

 

It looks like Acacia Longofolia but I'm not sure it is an Acacia the leaflets don't look right.
I know some Acacias have both pinnate and phyloid leaves on the same plant but this looks different, a mutant Gleditsia?

 

I've grown acacias fron seed before, the juvenile leaves are like that, complete and totally unlike the usual ferny leaves

 

So have I but I thought at the size in the pic the leaves are usually are of one type or the other. Perhaps it is Acacia Longifolia, I have two month old seedlings of Longifolia which as you say have two types of leaf.

 

Thankyou everyone, yes I do have an Acacia so it must of seeded itself, Thanks again

 

Can you take a pic of the older acacia?.....so we can identify which species it is.

 

Sorry only just seen your reply here are some pics

 

That looks like Albizia Julibrissin to me. In your pic it is dopping leaves as most Albizias do. Most Acacias are evergreen.

 

Looks like a tropical stow away accacia, I get loads of these in my tree ferns which seem to love germinating in the trunk. I have one which I removed and planted in a pot. They get quite big quite quickly, fully hardy so far and respond well to heavy pruning if you want to keep the juvenile fern leaves.