The secrets to this method are ::
1. A giant punch bowl + giant flowers. Scale is critical.
2. Floral foam holds the flowers in place. The heavy heads of the hydrangea would droop otherwise.
3. Add more water to the floral foam each day so it doesn't dry out.
4. Smash the ends of the stems to allow water absorption. Woody stems require "opening" up.
Why is this a good arrangement? It makes the table fabby in just minutes. Look at how grand it can be. Summer dinner party? Check.