Very sick fuscia

I planted some fuscia last year that I grew from cuttings.  It's a very hardy fuscia that grows wild in our Irish hedgerows.  Three of the plants that I planted grew really well last year and are well up, but two of them seemed to really fail going into the winter.  They started putting on new growth this spring and seemed to bounce back, but all of a sudden the leaves just died off, in fact I thought the sheep that sometimes wander in had eaten them!  Now the one that was doing extremely well has started dying.  The other two now look dried up and dead.  The stems have become brittle, although they are still green inside.  I can't understand it, as everything else around them is doing well.  Any thoughts?

Have you checked for Vine Weevils eating the roots?

Well there are leatherjackets & vine weevils in my garden, but no other plants are effected.  I've also noticed that the cuttings I planted out the back garden which were also flourishing are starting to exhibit similar symptoms, but those that are still in pots are fine.  It does suggest it's something in the soil, but I must reiterate that these are wild fuscia and very very hardy.  We've had no frosts in my area since March as I'm on the coast, so it's definitely not frost damage.  Is there something out there that specifically attacks fuscia?