I assume by "green" you mean environmentally friendly and not the color green. Think potted and bedding plants.
I did an outdoor wedding at a Gazebo site at a country club. Although it was a beautiful setting, there was a drought and nothing was blooming. So I visited the local greenhouse and brought brightly colored purple bedding plants to the gazebo. I literally buried the trays in the ground, using extra peat to hide the fact that the flowers weren't actually in the ground. I planted a mixture of purple bedding plants in wired containers and set them on the rails.
I had one guest exclaim later how perfect the setting was because "the flowers were all the right colors!" She never dreamed that I had put them there. Later - I easily removed all the plants and put them in my own bedding pots at my home! Double use was wonderful!
At another outdoor wedding we used brightly potted azelas, mums,etc. down the aisle, wrapped in decorative foil. We clustered more on different elevations and stands around the archway.
The bride had the pleasure later of using these plants around her own home.
