To arrange a dozen roses in a vase, choose a vase that is approximately 5 inches across. Cut off all of the thorns that fall below the water level, and trim the stems so that the roses are double the height of the vase. Arrange the flowers in a tight group, pulling the middle stems up higher for a rounded arrangement.Continue Reading
Select a vase that is about 5 inches across. Both square and round vases work well. Using floral tape or masking tape, make a grid with two pieces of tape running one direction and three pieces running perpendicular to them.
Cut the stems of the roses so that they stand approximately double the height of the vase. Leave three or four of the roses about 2 inches longer. Strip the leaves and thorns off the bottom half of the stems.
Place your roses in the tape grid, putting the longer flowers in the middle. Keep the flowers in a tight bunch to help them last longer; the tighter arrangement provides additional support. Once every flower is in place, start moving the heads until they form a cohesive, rounded shape. Reposition the leaves so that they frame the edges of the arrangement.