Grebo

Hi, we have a well established hedge of Viburnum tinus, Lucidum. It's a good 3m high, over the last couple of years it's started to die off in places, no visible pests, no obvious fungi, like root rot or canker. The local garden centre suggested it could be the well water, but then there's not much we can do about that. Any other ideas ?

snikpoh

Can't help with Viburnum but we've lost most of our privet hedge. In total it must be nearly a kilometre long so you can imagine I'm none too pleased!

ned flanders

A kilometre long hedge. You must have felt very privet.

Retired in Euskadi

3m high sounds way over the top. I know it's easy to give advice when it's not one's own, but I'd give it a good hard pruning down to about a meter or less late spring (or after flowering). If you wish to keep the height for privacy however, then cut out all the dead stuff & burn it.
Not sure whether you can blame the well water unless there's herbicide run-off in it.

discoman

There is Honey Fungus (or its equivalent) in "my" part of Spain - Andalucia that is.....and that can be lethal for some hedging plants.

Grebo

Thanks for the suggestions, Snikpoh that's terrible, I really don't want to loose it as it's a major barrier between us & the main road.
The well water is a bit on the salty side but other than that it's pretty good & as it has grown this big I doubt that is the reason. Yes will give it a good trim this year, but it's def drying off. Lost 4 plants & two replacements aren't doing to well. They bud up nicely then leaves curl up & die.
Will look up honey fungus thanks.