An underwater floral centerpiece turns a run-of-the-mill vase of flowers into a stunning display suitable for any occasion. Tall, narrow clear glass vessels serve as the structural element for your display; flamboyant blooms such as roses, lilies or orchids show off their elegant looks even more when underwater, as the water tends to magnify them a bit. Clean any bits of dirt and debris off the selected flowers and stems before placing them in water, as those tiny particles may dislodge and float atop your display.
Inspect the flowers closely to remove any petals that are starting to wilt or that are damaged.
Hold each flower next to the glass vessel that will contain it. If you plan to include the stem in your display, trim it at a slight angle using garden shears so the flower stands 1/2 to 2/3 of the size of its respective vase or container. If you're including just the blooms of a flower, trim the stem so an inch or so of stem remains. This part of the stem allows you to tie on a weight so the flower doesn't float. If you don't mind if the flower floats, trim off the entire stem.
Run a small piece of floral wire through a fishing weight. Wrap the floral wire around the base of a flower stem to weigh it down in the vase. Skip this step if you want the flowers to move around underwater.
Set the weighted flower in the glass vase, holding it up with your fingertips so it is centered. Gently place a few polished river pebbles or glass floral gems in the vase so they surround the stem and hide the fishing weight.
Pour distilled water into the vase around the flower while holding the flower steady. Pour in enough water to cover the top of the flower by at least 3/4 inch. If you're creating a floating flower display, add the flower or flowers on top once the water reaches within an inch or two of the top of the glass container.