The simplest, most beautiful floral trend: rooting plants in water. All you have to do is snip a plant at the base of a leaf and place it in fresh spring water in a glass vase. I imagine this doesn't work for every kind of plant.
Orchid terrarium idea using a geodesic leaded glass container from Restoration Hardware, and phalenopsis and lady slipper plants. The environment is easier to control for some orchids when they are enclosed in glass.