If you are considering making your own bouquets I recommend two things: 1) this website http://www.bridecraft.com/hydrangea-bridal-bouquet.html and 2) Xanax (you're gonna need it if you're doing your own flowers). :-)
I am obsessed with light blue hydrangeas (achieved by increasing the acidity of the soil in which they are planted), whose centers often melt into a pale green, a combination which soothes me. My bridesmaids will be carrying bouquets made of 4 or 5 stems of light blue hydrangeas. The flowers will look fabulous against their black dresses. I am using this as inspiration:
I have two junior bridesmaids, who will be carrying the light green variety. This distinction between bridesmaid and junior bridesmaid bouquets serves two purposes: 1) to add another subtle color to the mix in order to please the husband-to-be (who does not hold a lot of stock in the colorfulness of the light blue), and 2) to visually create a special role just for the junior bridesmaids.
My bouquet will be a gathering of white hydrangeas and dusty miller accents. Something like this (although leaving the stems exposed to allow for watering in between photos and the ceremony):
When the bouquets are put together, it will look something like this:
If using hydrangeas, keep in mind the time of year you are getting married. The growing season is typically in the summer, but can last as long as October if you live in a good climate - like Los Angeles!