'Waterslide' is a new introduction from Proven Winners for 2017. It has wavy, ruffled leaves with heavy substance. The blue, rippled leaves look like water splashing in the shade garden, and hold their blue color well into the summer season. Lavender flowers appear on proportionate flower scapes in late summer. This medium-sized hosta is a perfect companion to 'Wheee!' and suitable for landscapes and containers alike.