There is something so romantic and soft about a room full of white hydrangea. The nice thing about using hydrangea is that you don't actually need a lot of flowers to have an impact. And I think they look stunning all massed together with a few dark green accents. But be careful with hydrangea as they are very sensitive to heat and can wilt! Hydrangea is also very unpredictable, it may last anywhere from two to six days.