Instead of going with plastic Easter grass, try using 100% biodegradable fine wood shred (also known as wood excelsior or wood wool). This shred can easily be dyed using gel icing coloring found in your craft store's cake decorating section. Just mix up some of the gel, water and a little bit of vinegar (I used a tsp or so) to the color you desire. With all the different gel colors available you can mix up your own custom color! Then soak the wood shred until it reaches the color saturation you want. Finally let air dry on some paper towels. Once you get going, it will be hard to stop yourself as you will be tempted to make many a rainbow of colors. You can also add glitter to the grass to give it some sparkle.
Here is the'before' shot of the Easter grass still in its natural shade (which is still lovely, but for Easter it is fun to have some color).
P.S. I found the vintage Italian pressed glass dessert cups at a Thrift Store ($1 each!).