Prepare the flowers. Release the petals from six white roses by pulling gently on each petal. Take any leaves off of the carnation stems. Place the pink and white carnations to the side of the soda glass. Measure the stems and cut them so that the carnation tops stand just above the glass rim.
Fill the soda glass to the rim with the white petals, which represent vanilla ice cream.
Place the pink carnations, which look like strawberry ice cream scoops, tightly around the edges of the soda glass. Pack the center of the soda glass with white carnations so that they look like whipped cream.
Cut a red rose so that there are 4 inches left on the stem. Slide the rose down between the carnations. This acts as the sundae's cherry.
Add a straw to the soda glass. Push the straw into the flowers near the outer edge of the glass.