Flowers 
Fresh flowers breathe life into any celebration. Here are a couple of tips to make sure mama nature approves:
Opt for Potted Plants
Imagine carrying a bouquet that you can later plant in your garden--how cute is that! Visit your local florist for custom live arrangements, or if you have a green thumb of your own, you can get eco-friendly supplies here:
Choose Organic
If you prefer cut flowers, make sure they're pesticide-free. Here is a link to a great service which donates part of their proceeds to charity: