Dora: if the bloom is smaller than you stated, I would ID it as H. 'Lemon Lime'. There are quite a few photos of that cultivar in the database and it was widely available a few years ago. If it is actually 6" across then its much harder to ID. There are several larger ones that had a pale green undercast to them, such as H. Luna, but I don't know of any of the bigger ones that were actually a pale green. Do you expect it to bloom again this season? The size of the flower is the deciding factor in ID this as Lemon Lime.
