Hi,

I have a 4m high by 9m long conifer hedge. It is either a leylandi or
thuja type, although I have done some research I cannot be exactly
sure.

The hedge is made up of 4 trees, and since its last pruning about 6
months ago (which I did not do), some brown patches have appeared,
majority on 1 tree, slightly on another and none on the other 2.
I have researched the potential cause of the browning, and know it
could be due to many causes, and that it may never recover. One of
these could be some kind of insect infestation.

In the scenario of an assumed insect infestation I was thinking of
getting some insectiside and spraying the hedge. I am under the
opinion of spraying it for the sake of it will at least eliminate an
insect cause, even if not actually present.

I haven't got a clue what type of insectiside to use or what
equipment. Also the potential side effects on the hedge itself,
flowers and other plants in the same soil, animals and children.

Can anyone give me any advice?

Thanks,

James

wrote:
: Hi,
:
: I have a 4m high by 9m long conifer hedge. It is either a leylandi or
: thuja type, although I have done some research I cannot be exactly
: sure.
:
: The hedge is made up of 4 trees, and since its last pruning about 6
: months ago (which I did not do), some brown patches have appeared,
: majority on 1 tree, slightly on another and none on the other 2.
: I have researched the potential cause of the browning, and know it
: could be due to many causes, and that it may never recover. One of
: these could be some kind of insect infestation.
:
: In the scenario of an assumed insect infestation I was thinking of
: getting some insectiside and spraying the hedge. I am under the
: opinion of spraying it for the sake of it will at least eliminate an
: insect cause, even if not actually present.
:
: I haven't got a clue what type of insectiside to use or what
: equipment. Also the potential side effects on the hedge itself,
: flowers and other plants in the same soil, animals and children.
:
: Can anyone give me any advice?
:
: Thanks,
:
: James

Sounds like bad pruning has led to die back to me. I wouldn't spray at all,
certainly not just on the off chance as the whole food chain can be
interrupted let alone any beneficial insects getting zapped

"Robert (Plymouth)" writes
wrote:
: Hi,
:
: I have a 4m high by 9m long conifer hedge. It is either a leylandi or
: thuja type, although I have done some research I cannot be exactly
: sure.
:
: The hedge is made up of 4 trees, and since its last pruning about 6
: months ago (which I did not do), some brown patches have appeared,
: majority on 1 tree, slightly on another and none on the other 2.
: I have researched the potential cause of the browning, and know it
: could be due to many causes, and that it may never recover. One of
: these could be some kind of insect infestation.

What kind of insect infestation? It affects what treatment is
appropriate.
:
: In the scenario of an assumed insect infestation I was thinking of
: getting some insectiside and spraying the hedge. I am under the
: opinion of spraying it for the sake of it will at least eliminate an
: insect cause, even if not actually present.

Not necessarily. Insect pests are becoming increasingly resistant to
available pesticides.
:
: I haven't got a clue what type of insectiside to use or what
: equipment. Also the potential side effects on the hedge itself,
: flowers and other plants in the same soil, animals and children.

Sounds like bad pruning has led to die back to me. I wouldn't spray at all,
certainly not just on the off chance as the whole food chain can be
interrupted let alone any beneficial insects getting zapped

I'd agree. Assuming you manage to avoid spray drift and keep animals and
children away, the killing of beneficial insects may mean you have more
problem from other insect pests on other plants (plant eating insects
are adapted to breed quickly once a food source is found; predators
obviously are slower to react since there is no point in their
populations building up until the prey population has established
itself). In addition, some insecticides have adverse effect on
particular types of plant.

Reading the list of precautions on any insecticide bottle suggests that
these are serious chemicals, and the thought of spraying 'for the sake
of it' even if there are no pests present rather alarms me. Remember too
that many pests will have been killed off by the cold winter, and in
this case spraying is a waste of money.


--
Kay

wrote in message
ps.com...
Hi,

I have a 4m high by 9m long conifer hedge. It is either a leylandi or
thuja type, although I have done some research I cannot be exactly
sure.

The hedge is made up of 4 trees, and since its last pruning about 6
months ago (which I did not do), some brown patches have appeared,
majority on 1 tree, slightly on another and none on the other 2.
I have researched the potential cause of the browning, and know it
could be due to many causes, and that it may never recover. One of
these could be some kind of insect infestation.

In the scenario of an assumed insect infestation I was thinking of
getting some insectiside and spraying the hedge. I am under the
opinion of spraying it for the sake of it will at least eliminate an
insect cause, even if not actually present.

I haven't got a clue what type of insectiside to use or what
equipment. Also the potential side effects on the hedge itself,
flowers and other plants in the same soil, animals and children.

Can anyone give me any advice?

Thanks,

James

Spraying against aphids will probably make things worse as leylandi hedges
are major overwintering sites for ladybirds who will soon sort out any
aphids problems. browning of hedges is more likely due to wrongly
timed/badly done trimming or too wet/ too dry conditions.

--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collections of Clematis viticella (cvs) and
Lapageria rosea

wrote in message
ps.com...
Hi,

I have a 4m high by 9m long conifer hedge. It is either a leylandi or
thuja type, although I have done some research I cannot be exactly
sure.

The hedge is made up of 4 trees, and since its last pruning about 6
months ago (which I did not do), some brown patches have appeared,
majority on 1 tree, slightly on another and none on the other 2.
I have researched the potential cause of the browning, and know it
could be due to many causes, and that it may never recover. One of
these could be some kind of insect infestation.

In the scenario of an assumed insect infestation I was thinking of
getting some insectiside and spraying the hedge. I am under the
opinion of spraying it for the sake of it will at least eliminate an
insect cause, even if not actually present.

I haven't got a clue what type of insectiside to use or what
equipment. Also the potential side effects on the hedge itself,
flowers and other plants in the same soil, animals and children.

Can anyone give me any advice?

Thanks,

James

James-I agree with all the other comments.If the hedge is Thuja then it
should regenerate.I think the browning problem is possibly due to wind
burn.

wrote in message
ps.com...
Hi,

I have a 4m high by 9m long conifer hedge. It is either a leylandi or
thuja type, although I have done some research I cannot be exactly
sure.

The hedge is made up of 4 trees, and since its last pruning about 6
months ago (which I did not do), some brown patches have appeared,
majority on 1 tree, slightly on another and none on the other 2.
I have researched the potential cause of the browning, and know it
could be due to many causes, and that it may never recover. One of
these could be some kind of insect infestation.

In the scenario of an assumed insect infestation I was thinking of

It is almost certainly not insects and even if it was, spraying with
insecticide usually does not help much and can even make thimgs worse.
Please don't. Seriously, it is a waste of money at best. Brown bits on
conifer hedges are part of teh package.

getting some insectiside and spraying the hedge. I am under the
opinion of spraying it for the sake of it will at least eliminate an
insect cause, even if not actually present.

I haven't got a clue what type of insectiside to use or what
equipment. Also the potential side effects on the hedge itself,
flowers and other plants in the same soil, animals and children.

Can anyone give me any advice?

Thanks,

James

"Robert (Plymouth)" wrote in message
...
wrote:
: Hi,
:
: I have a 4m high by 9m long conifer hedge. It is either a leylandi

If you find out what caused it, put it in a bottle and sell it ;-)

Charlie Pridham writes


Spraying against aphids will probably make things worse as leylandi hedges
are major overwintering sites for ladybirds who will soon sort out any
aphids problems. browning of hedges is more likely due to wrongly
timed/badly done trimming or too wet/ too dry conditions.

Interesting article in latest issue of Garden by a lady who used to be
involved in research which used aphids to transfer viruses from plant to
plant thus requiring a good supply of aphids. When aphid populations
were waning, their approach was to spray once with an insecticide. This
killed all aphids on leaf surfaces but not those in nooks and crannies.
It also killed all predators (who roamed widely over leaf surfaces and
therefore picked up the insecticide). Resultant rebound from breeding of
the hidden-away aphids resulted in bumper crop of aphids within two
weeks.
--
Kay

On 12 Mar, 23:22, K wrote:

Interesting article in latest issue of Garden by a lady who used to be
involved in research which used aphids to transfer viruses from plant to
plant thus requiring a good supply of aphids. When aphid populations
were waning, their approach was to spray once with an insecticide. This
killed all aphids on leaf surfaces but not those in nooks and crannies.
It also killed all predators (who roamed widely over leaf surfaces and
therefore picked up the insecticide). Resultant rebound from breeding of
the hidden-away aphids resulted in bumper crop of aphids within two
weeks.

I was overwhelmed to see that article in The Garden mag. After so many
years we've been talking about this, it is amusing to see that it is
now taken seriously. I suspose it's because so many chemicals have
been removed from the shelves, plus the incredible invasion of a lot
of insects and their cheer numbers - we cannot pretend that nothing is
wrong any longer. A good balance of *all* insects is necessary to a
healty garden, that includes ants, aphids, spiders, snails etc.

"gentlegreen" wrote in
message k...

"Robert (Plymouth)" wrote in message
...
wrote:
: Hi,
:
: I have a 4m high by 9m long conifer hedge. It is either a leylandi

If you find out what caused it, put it in a bottle and sell it ;-)



For Leylandii I usually recommend aggressive pruning (cut back to just above
soil level) followed by a good concrete mulch or treatment with a flame
thrower. They respond really well with both.

On 13/3/07 10:38, in article ,
"Des Higgins" wrote:


"gentlegreen" wrote in
message k...

"Robert (Plymouth)" wrote in message
...
wrote:
: Hi,
:
: I have a 4m high by 9m long conifer hedge. It is either a leylandi

If you find out what caused it, put it in a bottle and sell it ;-)



For Leylandii I usually recommend aggressive pruning (cut back to just above
soil level) followed by a good concrete mulch or treatment with a flame
thrower. They respond really well with both.


A man after my own heart. ;-) I know they have their uses in the right
place but all too often they're in the wrong place!
--
Sacha
http://www.hillhousenursery.co.uk
South Devon
http://www.discoverdartmoor.co.uk/
(remove weeds from address)