Liquid feed for a Hornbeam hedge

I had intended to feed my 2 year old Hornbeam hedge this spring with blood, fish & bone but I've realised that I can't access the bottom of the plants now because of other plants in front of it and new seeds sewn etc.  and a 1 metre fence behind it.  

Is liquid plant food ok as an alternative?  I could easily apply that from behind the hedge i.e. over fence.