You can buy plant food specifically for acid plants, usually sold as Camellia or Azalea food, think Miracle Gro makes it. Otherwise, just rake in Growmore at the base in spring, as growth begins for both these plants, and then again six weeks later. If your hydrangea is turning lilacy pink, either stick with acid feed or give it a dose of Sequestrene iron tonic twice a year, and feed with Growmore as already suggested.

Just what I was going to suggest, Bamboo, and you got there first! I usde Sequestrene on my Camelias,and also on acers sparingly, as they also like an acid soil...Annie