I am wondering whether to plant two this Fall or wait until Spring.

I understand that if you plant them in the Fall they have time to develop root systems over the winter and perform in growth the following year.

How big of a difference would it really make if I planted them in early Spring instead?

Btw, I am in Tennessee.

Thanks for your information!!
I dont understand why everyone hates the look of Leyland Cypress trees!!

I think they look nice!!
And I want them to grow fast, so as to block the neighbors next to me.