here (PDF), taken from a presentation Piet gave to Friends of the High Line last year.
James Corner, the principal of Field Operations , who's working with Piet on the landscape design for the High Line, said, "He's like a really good chef. He knows his ingredients in a much deeper way than an amateur. He's a master of the medium."
Looking out over his perennial meadow, Mr. Oudolf articulated it this way: "You look at this, and it goes deeper than what you see. It reminds you of something in the genes - nature, or the longing for nature." Allowing the garden to decompose, he added, meets an emotional need in people.
"You accept death. You don't take the plants out, because they still look good. And brown is also a color."
A Landscape in Winter, Dying Heroically  (New York Times)
Slide Show: Artfully Planned Decay  (New York Times)
Piet's Web Site , with a 360 degree panorama of Hummelo
Piet has also written three fantastic books with beautiful photographs. The most recent is called Planting Design: Gardens in Time and Space . (Amazon)