I have this huge crush on art installations since I don't know when. And when it is done with natural flowers...ah, don't ask me. Anne Ten Donkelaar is one such artist who specializes in installations (read constructions) of flowers, twigs, broken wings of butterflies...well check it out yourself: http://anneten.nl/
Her flower constructions are 3d collages from pressed flowers and cut out flower pictures. Each element is meticulously placed on pins which creates the depth. Some of them are like a fantasy Herbaria, filled with dried flowers or branches, with irregular shapes and sophisticated twists and some refer to planets.