'Bali Hai' is a dormant diploid introduced in 1973 by Allen J. Wild. Check out more information about the family and their website: http://www.gilberthwild.com/
I have had this daylily in my garden for 20 years. It is reliably hardy and has always bloomed well for me. In my garden it is a smaller daylily and I have it at the front of a border along one of my garden paths.
I agree with touchof sky. I have Bali Hai in the front of one of my beds in zone 4, Minnesota. It is a reliable bloomer, somewhat on the small side and doesn't multiply fast in my garden. Still a beautiful flower!