Need Help . . Hydrangeas in an outdoor wedding???

I am getting married outdoors in mid-June 2008 in Central Washington. The temperture is projected to be in the 80s-90s in the late afternoon and evening. Everyone keeps telling me that my choice of hydrangeas is not going to work because they are going to wilt before the wedding is over, even if I keep them in water. Does anyone have experience with this flower? Is this true? If it is, any suggestions for a cornflower-lightblue flower instead? Thanks!