I have 2 wedding ceremony pieces to do today using a 2 1/2 foot cylinder vase. I am surrounding the interior w/ ti leaves and using delph, hydrandea, lizzies, dalias, callas, hanging amaranthus. I need height for the flowers. The pieces will be placed on wine barrels outside. I tried adding 5 lbs of river rocks and still need some more height. I would love some suggestions.