Coffee grounds for my hydrangeas?

I ran across an article that talks about saving up your coffee grounds for gardening uses. One coffee ground use for gardeners is to use them on your hydrangeas. I love my hydrangeas because you can change their color by tweaking with the acidity/alkalinity of the soil. Coffee grounds are acidic, so the coffee grounds should make them a nice blueish purple for me. It is always good to find green gardening tips and extra exciting when they are cheap too! Hubby may just need to drink some more coffee at home this spring.