hawthorn 3yr old hedge - plants slowly 'dying' one by one...

Hhmmm... poor little plants don't have much chance anyway as they were planted beneath mature trees against a perimeter fence & road round a school. kids run through the mature trees so i've already lost half the 'hedge' plants to kid damage. However in last few weeks i've noticed they're dying off (turning brown on leaves and eventually stem) one by one, starting from the far end and slowly moving round - currently there are 3 meters worth of hedgerow hawthorns in their various stages of 'dying' ... ground is rock hard, hardly gets rain. thought it was sun-scorch except it didn't happen at once to all plants. i keep the soil mulched & fed so not sure what's happening. school broke up for summer - i dont wanna come back in sept and find another 3 meters has died too... any ideas? shall i take a piece into a garden centre to ask? as i say, they're dying from the leaves inwards, the stems are last to die (or is that normal) ??? thanks guys

 

Before you give up post a couple of pictures on here for us to have a look at, members might just be able to help.

 

too much rain with poor drainage?

 

simply to dry? Dunno how much rain you had down there - we had plenty...
And if it rains it possibly runs off elsewhere (is there a slight incline?) because the ground is to hard and dry to soak it up? You said you mulched, that should normally help to keep it moist or soak up rainfall. is the mulch applied thickly ?

 

If the ground is rock hard, can we take it its clay? I think hawthorn doesn't like compacted clay.

I also wonder if you can save the dying trees by cutting them back severely. Hawthorn responds very well indeed to brutal pruning, but I suspect at 3 years old they may not be ready for that yet.