It's not simply super hydrophobicity though. While it does employ a contact angle greater than 150 degrees between that and water (that is the defining characteristic separating hydrophobic and super hydrophobic), what it's meant though is that it's also self cleaning as well; but that is just an extension due to its super hydrophobic properties.
The lotus employs nano-scale hair-like tubes, which gives it its roughened microscale surface. Although the waxy cuticle of the leaf itself is not super hydrophobic, the nano structure is what enables it to be super hydrophobic. This surface is also not charged as well, giving no adhering properties to the dirt or dust that may fall on it. So by decreasing the adhesive forces of water to the surface and making it so that water literally just slides off the second the leaf is tilted even abit, it is able to self clean in the sense that water's natural attraction and ability to encapsulate dirt/dust given its extremely polar (hydrogen bonding) nature make it good at capturing dirt, and by simply when rain befalls it, it agitates the leaf, making it tilt one way or another, allowing the encapsulated dirt-water particle to simply slide off.
Sorry if it got abit too detailed; did quite abit of research on these last year haha. Although the salvinia molesta is what caught my attention for one of my paper's this year (it's nano-scale hairs are hydrophobic at the root and shaft of the hair, but at the tips, its hydrophilic, so it actually is able to create a layer of air on its surface and can survive for a really long time if it becomes submerged).
Man I'm such a dork... Haha