No success this year!!

Hydrangeas are not heavy feeders like roses are. Established hydrangeas planted in the ground can feed off their decomposing mulch. They do not need fertilizer unless there are some soil nutrient deficiencies (say, your soil is sandy or is lacking phosphorus/etc.) or if the plant was recently planted/transplanted. You can give them a single application of organic compost, composted manure or cottonseed meal. Or you can use one Spring application of a chemical fertilizer that is general purpose, slow release, with a NPK Ratio of around 10-10-10 (if there are no soil nutrient deficiencies). Be careful with some Miracle Gro products as some formulations are 30% nitrogen (NPK 30-x-x). Amend the soil regularly if your soil is alkaline.

Hydrangeas planted in pots will require more frequent fertilizer and amendment applications due to the constant watering.

 

Thanks guys, I appreciate the replies. Well it seems like I have been doing the wrong thing with the food. Advice noted in my little book!
One other thing that I have just thought about, I live on the outskirts of Caerphilly, next to farmland, we are also on a hill. The sheep and cows poop all day long in the field next door and the rain water flows down into the garden. In fact a couple of years ago I had to get in the field to dig a trench to divert the flow of water off the field as it was about to wash the garden away. So, liquid poop! Any good for flowers?