Posted: 25/02/2017 at 14:14
They're pretty straightforward shrubs. I wouldn't bother feeding as they've had quite a lot of stuff already. If you wait a month and give them a general feed then - not too much, something like a sprinkle of Blood, Fish and Bone - and then mulch with the manure, that should be plenty. Make sure they've been well watered ( not usually a problem at the end of winter ) before applying the manure mulch. That'll help them retain moisture and will feed the soil. It's something you could do in spring and autumn.
Then let them grow away. See how they are in a few months, and if they still look a bit pale, do a foliar feed then.
You can add the bark as well on top if you want, but I'd keep that for a later date as a mulch, or use it elsewhere in the garden for now.
Pruning helps them thicken up, so carry on keeping them trimmed as you've been doing. They naturally want to grow big and wide, so it can be an issue trying to keep them as a narrow hedge. Better to keep them tidied up a little, regularly, instead of letting them get big and then having to hack them back.