Rosie -
Hello neighbor! I live in Durham and grow many types of iris. I have mostly bearded iris - from minatures to talls, but do grow Lousiana and Japanese as well. If you are over my way in late April or all of May, I can show you my iris. That may help you decide which types you would like to grow.
I mix the colors in my gardens, and plant the dwarf and intermediate (smaller/shorter) iris in the front of each bed with the talls in the middle and back. You probably have a lot of clay in your soil so I suggest mixing in some good garden soil as well as compost. I make raised beds myself since my ground is so hard. I shovel out the grass, then break up the underlying soil. I then build the garden edge. I use wall stone because it won't break down over the years like wood, then put down a layer of paper and cardboard (to help prevent weeds growing up). Then I add a good eight inches or more layer of the garden mix I get from Poultry Villa and I am ready to go! I have a friend with a dump truck, so he drops off however many cubic yards I need.