Acacia stenophylla I believe. Here is the one that sprouted near my foundation of my house in Sun Lakes, AZ. I posted on a Facebook page and everyone recommended taking it out because it is a very messy tree and sprouts all over the place. HOWEVER, if I were you, I would go to a local nursery like Treeland etc. with a piece of it and maybe your photo and find out for sure what it is. May actually be a desirable different species of Acacia.