Google, Vine, Twitter, Bitly, Birchbox and Spotify may be very different companies, but they're the same in the respect that they're among the dozens of major brands paying as much as $100K each for a tiny, 10-person startup called The Sill to equip their NYC spaces with office plants. And we don't mean a few simple potted plants on shelves and desks—we're talking hanging flowers, greens planted into furniture and entire plant walls.