I always love when people make flower arrangements and fill the vases with interesting objects. Unfortunately, if you use a filler that isn't waterproof, you have to use fake flowers. Or do you?
Here is how you can do this with water and real flowers.
First get a vase, a smaller vase or glass that will fit inside the larger one, and enough filler.
Place the smaller glass inside the larger one, centering it the best you can.
Then pour your filler in between the large and small vases.
Now you can put your flowers in the center... water and all.