We have a Grevillea on the corner of a well drained, raised bed. It's been
there for many years but now is turning brown and dying off in patches here
and there. They're such good value plants and flower on and off for such a
long time that we're rather sad at the thought of losing this one. Is
anyone familiar with gradual dieback in these?

--
Sacha
http://www.hillhousenursery.com
South Devon
(new website online but not completed - shop to come and some mild tweaking
to do!)

Sacha wrote:
We have a Grevillea on the corner of a well drained, raised bed.
It's been there for many years but now is turning brown and dying off
in patches here and there. They're such good value plants and flower
on and off for such a long time that we're rather sad at the thought
of losing this one. Is anyone familiar with gradual dieback in these?

Many refs on the internet to dieback in Grevilleas. Usual cause is
Phytophthora.

You might get away with heavy pruning; it's worth trying as Grevilleas are
very fast growing.

there may be other causes, of course. Any weedkiller spraying been going on
nearby?

--
Jeff
(cut "thetape" to reply)

On 19/6/08 10:41, in article ,
"Jeff Layman" wrote:

Sacha wrote:
We have a Grevillea on the corner of a well drained, raised bed.
It's been there for many years but now is turning brown and dying off
in patches here and there. They're such good value plants and flower
on and off for such a long time that we're rather sad at the thought
of losing this one. Is anyone familiar with gradual dieback in these?

Many refs on the internet to dieback in Grevilleas. Usual cause is
Phytophthora.

Ugh. I hope not but will take a look. Everything else seems healthy
including its flowering Cordyline neighbour.

You might get away with heavy pruning; it's worth trying as Grevilleas are
very fast growing.

Ray was going to do that so I'll urge him on!

there may be other causes, of course. Any weedkiller spraying been going on
nearby?

Definitely not.
--
Sacha
http://www.hillhousenursery.com
South Devon
(new website online but not completed - shop to come and some mild tweaking
to do!)

On 19/6/08 10:41, in article ,
"Jeff Layman" wrote:

Sacha wrote:
We have a Grevillea on the corner of a well drained, raised bed.
It's been there for many years but now is turning brown and dying off
in patches here and there. They're such good value plants and flower
on and off for such a long time that we're rather sad at the thought
of losing this one. Is anyone familiar with gradual dieback in these?

Many refs on the internet to dieback in Grevilleas. Usual cause is
Phytophthora.

You might get away with heavy pruning; it's worth trying as Grevilleas are
very fast growing.

there may be other causes, of course. Any weedkiller spraying been going on
nearby?

Whoops! Hit 'send' too quickly. I meant to say 'thank you'!

--
Sacha
http://www.hillhousenursery.com
South Devon
(new website online but not completed - shop to come and some mild tweaking
to do!)

On 20/6/08 08:55, in article ,
"Chris Hogg" wrote:

On Wed, 18 Jun 2008 23:28:38 +0100, Sacha
wrote:

We have a Grevillea on the corner of a well drained, raised bed. It's been
there for many years but now is turning brown and dying off in patches here
and there. They're such good value plants and flower on and off for such a
long time that we're rather sad at the thought of losing this one. Is
anyone familiar with gradual dieback in these?

I lost one earlier this year that had shown signs of dieback last
year, after having previously been quite healthy (G. Canberra, IIRC).
I attributed it either to salt gale damage or the wet summer in
conjunction with too rich soil. Hadn't thought of phytophthora though.
AIUI phytophthora flourishes in warm wet conditions. I lost several
ceanothus and one or two other shrubs last year which went in much the
same way, so perhaps it's in my soil. A camellia planted in place of
the grevillea is looking decidedly poorly :-(

Is there any relatively simple way of sterilising soil infected with
phytophthora, available to the amateur (Jeyes Fluid rings a bell)?
Alternatively, what shrubs are resistant to it, do you know?

Chris, have you checked for honey fungus?

--
Sacha
http://www.hillhousenursery.com
South Devon
(new website online but not completed - shop to come and some mild tweaking
to do!)

In article ,
Chris Hogg writes:
|
| Is there any relatively simple way of sterilising soil infected with
| phytophthora, available to the amateur (Jeyes Fluid rings a bell)?
| Alternatively, what shrubs are resistant to it, do you know?
|
| Chris, have you checked for honey fungus?
|
| Er...no, good point, although no sign of fruiting bodies. I'll check
| for bootlaces under the bark.

Unfortunately, there are a zillion soil-borne organisms that can
cause those symptoms, including thousands of species of fungi.
I doubt very much that you will see bootlaces on a plant that is
even partly alive, and you are more likely to see a white or
yellow mesh - which won't identify the fungus!

Soil sterilisation doesn't work on any of them, with any reasonable
reliability. The reason is that the organism will be back as soon
as the poisonous concoction wears off. Going for resistant varieties
isn't easy when you don't know what the organism is.

The only practical solution is improve the growing conditions,
and it's pretty hard to avoid waterlogging when it doesn't stop
raining.


Regards,
Nick Maclaren.

On 20/6/08 18:11, in article ,
"Chris Hogg" wrote:

On Fri, 20 Jun 2008 09:25:33 +0100, Sacha
wrote:

On 20/6/08 08:55, in article ,
"Chris Hogg" wrote:

On Wed, 18 Jun 2008 23:28:38 +0100, Sacha
wrote:

We have a Grevillea on the corner of a well drained, raised bed. It's been
there for many years but now is turning brown and dying off in patches here
and there. They're such good value plants and flower on and off for such a
long time that we're rather sad at the thought of losing this one. Is
anyone familiar with gradual dieback in these?

I lost one earlier this year that had shown signs of dieback last
year, after having previously been quite healthy (G. Canberra, IIRC).
I attributed it either to salt gale damage or the wet summer in
conjunction with too rich soil. Hadn't thought of phytophthora though.
AIUI phytophthora flourishes in warm wet conditions. I lost several
ceanothus and one or two other shrubs last year which went in much the
same way, so perhaps it's in my soil. A camellia planted in place of
the grevillea is looking decidedly poorly :-(

Is there any relatively simple way of sterilising soil infected with
phytophthora, available to the amateur (Jeyes Fluid rings a bell)?
Alternatively, what shrubs are resistant to it, do you know?

Chris, have you checked for honey fungus?

Er...no, good point, although no sign of fruiting bodies. I'll check
for bootlaces under the bark.

I really do hope it's not that and it probably isn't. But when things start
to keel over next door to one another, it's certainly something to consider,
at least and to check for. The bootlaces will be in the ground. I know
that when it was found in a previous garden of mine, the first sign was
these mysterious deaths of otherwise healthy plants. One day fine, next day
not so fine, a day or five later, gone.
The RHS site is pretty informative, I think:
http://www.rhs.org.uk/advice/profile...ney_fungus.asp

--
Sacha
http://www.hillhousenursery.com
South Devon
(new website online but not completed - shop to come and some mild tweaking
to do!)