I forgot to post the picture

I'm thinking that you are right; that it is a mimosa tree. The red fairy duster here has much shorter fronds. Also, I've never noticed it having seeds. Did you have seeds on yours when you had it? Lots of seeds in these pictures so maybe my bush is not being visited by the right pollinators.

I need to correct something I said on another thread about not seeing seeds on a Kidney wood tree. I never noticed any on my tall tree, which was pretty tall when I first planted it, but on the seedling Kidney wood I see lots of seeds. It's just that they are the size and shape of the foliage and thus are not noticeable at a distance, at least they were not to my eyes.

I never saw any seeds on mine, but I know you can buy seeds.

I have collected what I thought was Kidney wood seeds from our small tree.

The Mimosa will have to be dug out. Maybe someone will want it.

I just noticed an old seed pod on the Baji fairy duster I bought about a month ago. I think it came with it. From where the plant came I don't know, but hope it makes some seeds for me.