That it's necessarily about nature is a bit of a misconception. Haiku is supposed to be about "the nature" of what you are describing and nothing past it. You as a poet are not to interfere with what you are describing... it's about "a few strong images presented in simple language," says the textbook I have in my lap.
Just create something completely sensual. How it looks, how it feels, how it sounds. It's about images...
Officially the syllable count is 5-7-5, but then again, that's not the crucial element of Haiku... a few strong images, in simple language. Haiku isn't about your style, it's about content, it's about what you write, and what the reader sees when they read it...
Haha, personally I don't like Haiku...