Question
I saw a demonsration on a very tall bronze urn type arrangement that I loved. The designer used an oasis wreath to give the illusion that there were flowers covering the whole top of the urn. Could I do the same thing with a clear vase or would it show that there are no flowers in the center. This is for a wedding and the vases will be on round tables so the guests would be looking at the arrangment from below. (The vases are about 4 feet tall.)

Answer
If the vases are tall enough then yes, you would get the fullness effect.  The concern would be in the ability to see through the glass up into the mechanics of the design.  You would have to disguise the bottom of the wreath or whatever your mechanic was to have the idea work well.