In article ,
Tahiri wrote:
A recent thread contained the following comment :-
'The only common UK plant I can think of that seriously causes problems
is walnut which really does have a potent anti competition compound in
its roots called juglone.'

I did not know of this until now. I wish I had known thirty years ago when I
planted a walnut tree about six or so feet from a hedge! We didn't notice
the hedge dying until it was too late as the ivy and brambles are still
healthy. At least now we know why it died...

According to wikipedia some plants are badly affected by juglone and some
not at all affected.(No examples of the latter are mentioned) Does anyone
know of anything in the 'not affected' category that might be usable to
patch the hedge?

It's crap. Firstly, the tree that causes that effect is Juglans nigra,
not Juglans regia and, secondly, the effect is fairly minor - indeed,
I don't even know what plants are definitely affected. My mother had
shrubs growing under a J. nigra, and I have Hamamelis, Viburnum,
Helianthemum and Berberis growing under a J. regia.

What will have happened is that the tree took the water, nutrients and
light from the hedge, and it probably failed because it was out-competed.
Brambles and ivy are undershrubs and are adapted to that. I am not sure
what hedge plants do best as underplants, but I have seen yew and holly
growing as such in woodland.


Regards,
Nick Maclaren.