Hostas ‘Krossa Regal’ and ‘Regal Splendor’ have long been admired for their distinctive upright vase-shaped habit. The new ‘Regal Supreme’ has all of the wonderful traits of its parent, ‘Krossa Regal’, but it displays a significantly wider leaf margin than ‘Regal Splendor’. In spring, frosty blue leaves of good substance display wavy, creamy yellow margins. In summer, the color transitions to blue-green with wide, creamy white margins. Like its parent, lavender flowers appear on very tall scapes in mid through late summer.