Cut the flower stems at a 45-degree angle with shears. Leave an inch of stem attached to each blossom.
Thread a small fishing weight onto a short length of green floral wire. Wrap the wire around the stem of one or more blooms to secure the weight in place.
Fill the vase with a 1- to 2-inch layer of clear or colored floral marbles. Alternatively, you can use smooth stones.
Add distilled water to the vase until it is about half-full. Distilled water is preferred, especially in areas with hard water that can cause cloudiness. Place the blossoms inside and gently push them under the water. Use a long wooden skewer to move the flowers into the desired position and to dislodge any air bubbles caught between the petals.
Pour more distilled water into the vase until it is filled to within 4 inches of the rim. Submerge additional unweighted blooms on top of the first layer until the top of the blossoms sits 1 inch beneath the water's surface.
Set a floating candle on top of the water's surface. If you're using a wide vase, set multiple candles around the blooms. The candles prevent the submerged flowers from floating to the surface while adding a decorative finish to the arrangement.