What are the newest and most cost effective for floral centerpieces, for a summer tent wedding?

I'm planning a wdiing for mid July, on a Sat. night in a tent. The overall effect will be formal, as the tent will be dd with creme organza, the tables will have an overlay of sheer ivory, w/ gold ribbon entwined, and the tble will be adorned w/gold charger plates, etc. I need some ideas for a very sophisticated centerpiece,(Low on the table) and need some suggestions. Is Green hydrangea, viburnum, creme and or coral peonies available in July?..And what kind of container and style? Thanks.