I live in Mukwonago (zone 5a), similar to your 5b. I look for certain things when I search the online sites for dls.
I want hardy( dormant) extended bloomers (reblooming) which start early in the season (E, EM, EL) or midseason (EM, M, ML). Go to Garden.org, the AHS database and look to see if any awards have been granted. One of my favorite (though oftentimes overlooked) daylillies is When My Sweetheart Returns. The reblooming is so continuous it appears to be blooming from May straight through to September.
Another fabulous daylily is Karol Emmerich's Shout from the Mountaintop
