First of all, thank you for the acorns.
I have no idea what the name of this one is. We planted it over 20 years ago when we moved to AR. I do know, however, that it is an Encore variety and I purchased it for that reason as well as the fact that it had different colored blooms on the same plant. I was afraid I might have to do a big search for the picture, but found it right away. Here it is: