I've used the Edelweiss hop blend in my last few kolsch recipes, and it turns out amazing. Lots of nice noble hop notes, and I get a gorgeous floral component in the taste and aroma that meshes well with typical kolsch yeast strains. In fact, I brewed this recipe again yesterday -- 1 oz. early in the boil, 1 oz. late in the boil, to hit ~24 IBU.