It might seem wasteful to you to decorate and use all of these cut flowers in order to make a big room beautiful for one night. Are there any environmentally friendly options?
Change the setting
The easiest way to keep from using cut flowers and dried petals is to have your reception and ceremony outside. This sounds like trouble in the making, but it's a lot easier than it sounds. If you have a large space in someone's yard or in a park(with everyone's permission), you can set up a large tent for the reception hall and even the ceremony if you'd like.
Since guests will be under a roof, there is little need for worrying about the weather and they can still see the beauty of the outside as they eat. Find a beautiful setting and light some lanterns around the tent, it creates a soft glow well into the evening.
Of course, if you're looking for the most earth friendly eating options, you will want to select the buffet option with a limited portion of food. Any additional food can be donated to the local shelter if you'd like.
You will not be using any plastic forks or cups, so you will need a lot of glasses and silverware to make sure that you don't run out. Napkins can be cloth and washed instead of thrown out.
As decorations, you can spread lavender along the tops of the tables and then include small tea lights as well as larger candles as needed. Find candles that burn clean (as soy ones do), and these are quite friendly to use.
If you're looking for a centerpiece, you can choose to have tall silver or gold vases in the middle (metal) and fill them with ice and a bottle of champagne for the table. This looks great, plus it serves a function. You can then give away the vases for planters at the end of the night.
Using kegs instead of individual beer cans is a great way to cut back on waste-even if it can be recycled. Recycling tends to be more and more difficult to do as the night goes on.
Let the conversation and the happiness decorate the night, not things that you will only throw away the next day. Being earth friendly isn't difficult when you think of other ways that you can use things after the wedding is over.