Lucy, I love the dwarfs for edging! I love all the small/intermediate types- they're very user friendly for the mixed border....and the gardener who bites off more than he can chew sometimes, LOL.
"...and don't think the garden loses its ecstasy in winter. It's quiet, but the roots are down there riotous." Rumi
You should come to the Bluegrass Iris Society meetings. We have several experts and hybridizers who can help you out as well as a sale of all sorts of varieties that will bloom well in KY! We meet on the third Thursday every other month in Lexington. See our FB page and website bluegrassiris.org