Teresa - I hope you are able to source it in the USA. Someone, somewhere probably has it and could spare a piece if you can't find it in a nursery. It's a wonderful little hosta. 'Kinbotan' which I also have is similar but the leaves aren't wavy. It would likely work as well. And I have another large border of 'Lemon Frost'. Any of the 'Lemon Lime' family of hostas would work well as a border. That includes 'Lemon Frost' and it's sports:
-> Iced Lemon (yw)
-> Inky Dinky (wg)
-> Lemon Delight (gy)
-> Lemon Frost (yw)
-> Lemon Sorbet (yw)
-> Lime Meringue (gw)
-> Twist of Lime (yg) -> Twist of Green (gg)
This picture is my 'Lemon Frost' border.
And this is 'Kinbotan' which is similar to KKM.