problem with Thuja

At the beginning of April this year I planted a hedge of 16 pot grown Thuja Plicata, alternate Zebrina (approx 3 foot high) and Altrovirens (approx 5 foot high).

Within about 3-4 weeks a strip of 12 trees showed signs of browning from top to bottom on the side adjacent to my neighbour and by mid June they were totally devoid of any greenery.

What I can�t understand is that they were planted behind a conifer bed that was established 4 years ago with outstanding success and not a single plant loss. Nothing either side of the affected trees has suffered in any way, including the remaining 4 newly planted Thuja and the inevitable weeds which continue to flourish all around.

The new trees were given exactly the same care and attention as the established trees yet the results have been distressing.

I have never seen evergreen trees turn brown so quickly, it was as if they had been sprayed with brown paint! So fast was this process that my initial thought was that they had been damaged maliciously, particularly with 4 of them remaining quite healthy to this day!

I will be replacing the affected trees in autumn but before doing so, is there any test I can do on the soil and/or the dead trees to determine the cause of the problem and ensure I don�t have a repeat?

 

I would lift one and take a good look. Your desription sounds like a root problem - could be that they were infected with vine weevil before they were planted?

 

Thanks Fran, that was my immediate response, have a look at the rootball, but there was absolutley no sign of any infestation whatsoever. I even called in the garden centre that supplied the trees and they were of the same opinion, nothing visible in the root. Anyone know how I could test part of the dead tree to establish cause of death?

 

Sounds malicious to me :(
Phone your local Dept of Agriculture office and ask about how to have a test done. It will probably cost you something
Of course .... you soil here could be contaminated. Would a local search pinpoint a possible contamination issue?

 

Hi Briand. If the trees are only browning on one side it sounds to me as if they have been sprayed with weedkiller. Thuja are very good hedging plants because, unlike Leylandii, they will regrow if the foliage dies back. However, if it`s weedkiller they will not. David.

 

If there's no sign of root damage, and the browning is one side, then it may be the result of a spray.

Bearing in mind the danger of neighbour problems escalating and spoiling every ones lives - I would suggest a very gentle inquiring chat. You gotta live with them, and you don;t know what their experience with other neighbours have been. They may have experience leylandii <shock, horror>