The Superhydrophobic Surface of Nasturtium Leaves

Rain doesn’t happen too often in Southern California, but when it does, I always love the gleam it brings to the garden. And literally, too — the wide-spreading patches of volunteer nasturtium vines seem to sparkle with thousands of Swarovski crystals after a good storm.

Sometimes the raindrops roll off the leaves, or bounce as soon as they land, but many will pool on the lily pad-like surface and stand still until a breeze blows them away. They may even form patterns along the veins, as i...