Who needs flowers?
The other day I was on a walk and stole a few small branches of fresh sage from my neighbor's plant. After I used what I needed (to make this sage cocktail, which I also implore you to try), I stuck the leftover branches in a little glass of water. An effortless mini-centerpiece; easy!
Then I saw this great, similar idea on Remodelista: centerpieces from winter greens. Cheap and striking in their simplicity.
Try little buds in a simple glass, like these basic Mexican tumblers.