Ailing Cotoneaster

[my nellie]

My Cotoneaster has been affected by the last heat wave.
Some of the leaves were burned and the new shoots were shrivelled.
Moreover there was an attack by spidermites starting, so I sprayed the tree with an acaricide.
I have also removed all the affected leaves BUT the tree continues to decline, i.e. the leaves are getting dark brown from the tips and upwards.
Is this a problem of the roots? Some fungal attack?

This is how the tree was last May

And these are some photos of its current situation. I apologize for the poor quality of images but had not other than a mobile camera at the time...

The second spraying with acaricide is due to be done the next days BUT temperature is still very high 38-39 C (100,4-102,2 F)
If I was to spray with a fungicide also I could not because of high heat.... What can I do?
Do you have any suggestions?
Perhaps water with @Osoyoung advised peroxide solution?

Thank you in advance for any input!

 

[AlainK]

I think it should recover.

Don't over-water it, keep it in the shade.

I would not use too much chemicals on it. Try "cinamon tea" on the leaves for instance, and plant a few cloves in the soil.

If it doesn't help, at least it won't kill it....

 

[0soyoung]

Roots of most woody plants don't grow at temperatures about 35C or more.

My Cotoneaster has been affected by the last heat wave.

This makes me wonder if the roots of your plant didn't get cooked - they definitely will die at 45C and more.

Meat thermometer probes are available at grocery stores here for less than $15 US. I am reasonably sure that they also are inexpensive and readily available in Greece. Get one. Stick it in the pot amongst the roots and know how hot they are getting instead of guessing/imagining. Do what ever you must do to keep the roots cooler than 35C.

 

[my nellie]

Thank you both @AlainK and @Osoyoung for your suggestions.
I have already lost two trees (a Chaenomeles shohin and a Plumbago mini) due to this horrible climate.... Hot and stone dry! I had the Plumbago many years with me...

 

[petegreg]

Hi Alexandra, Osoyoung starts with Zero instead of O.
I hope your cotoneaster will get through it.

 

[my nellie]

Thank you Peter @petegreg
I'm afraid I do not understand well what you wrote about @Osoyoung and start with zero... ?

 

[petegreg]

Oh, the first letter of the nick is not a capital O, but zero, nothing more.

 

[my nellie]

Oh, now I understand the reason why I could not link his nickname
Thank you for the clarification @petegreg !

 

[defra]

Cotoneaster are tough itl pull trough!
Sad to hear you lost two tree's

 

[Anthony]

Alexandra, did a check, cotoneasters have a zone 8 limit.
Might be better to try something local.

News to share with you.
Planted a pencil thick pomegranate about 1 m tall, airlayer, on the lawn.
This was in January.
Soil in pot was commercial peatmoss / perlite mix out a bag from Canada.

Today it is 2 m and 2.5 cm thick trunk .

Will airlayer the lower branch to save.

These trees, originally from India grow themselves to death, takes about 25 years.
So like the maple which will die within 4 years with no winter, the pomegranate
can only live around 20 to 25 years down with no rest.
Good Day
Anthony

 

[AlainK]

Might be better to try something local.

Anthony's right: if tropical species can more or less be successful in temperate climates ( I've long given up myself ), I think it's impossible to grow species that require a period of temps at least slightly below zero for a few days in a conutry which is dry and warm.

If you can see cotoneaster in gardens (I mea planted in the ground) that look fine, then try it.

Otherwuise there are many species that can thrive in Greece, "zone 9a".

Went to Portugal in late autumn and saw extraordinary Bougainvilliers in full flowers, hundred of year-old olive trees, etc.Pomegranate, different kinds of citrus too, etc. could make much more rewarding work I think...
Montpellier maple, cork-bark oak, Quercus ilex (πρινόδενδρο, holm oak) are probably more challengi,g than cotoneaster, but they make great bonsai...

And ..................... do you have a garden, even a small one, or do you have a terrace, or a balcony ?....

"Environment" is the key-word. Natural environment is even much better and it's not only about climate..................

Do you know this other forum :

http://www.ausbonsai.com.au/forum/index.php?

 

[my nellie]

@AlainK and @Anthony thank you both for your replies.
I am growing my trees on my balconies. Unfortunately no garden...

a.- Cotoneaster
They do grow successfully here around my location in the ground.
I am thinking perhaps it was my fault... because one or two times I forgot to lower the awnings/sunshades soon enough and sunshine hit the plant directly for some time....

b.- Pomegranate
Anthony, I have a group planting (I will create a thread about it soon...) of pomegranates since 2014 (first put all together into a training colander by Mr. Peter Warren during a workshop...).
One of this year's shoots has reached 27cm as of today. Nothing crazy like the growth rate in your side, though.

On the contrary the longer shoot of my J. maple from last spring has reached 55cm! https://www.bonsainut.com/threads/unidentified-j-maple.26454/page-2
Regarding the Ficus carica stump from last February its longest shoot is now 34cm https://www.bonsainut.com/threads/ficus-carica-stump.27052/#post-480078

You are both right, Anthony and Alain and I have no objection on growing only natives.
Indeed, we have a lot of amazing species well suited for bonsai cultivation.

 

[my nellie]

Do you know this other forum :
http://www.ausbonsai.com.au/forum/index.php?

Yes, I do. Thank you.
I visit the webpage from time to time when in need of information.

 

[Anthony]

Hmm Alexandra,

my questions would be, out on your farm, is the soil stony, and if so do you compost.
We are naturally lucky,our soil is clay, very rich and on the side of a hill, freely draining.
A little compost and it just gets better.

Secondly, I wonder if your cotoneaster has the same situation the fukien tea has down here.

As a hedge, when the rainfalls it grows and can be clipped.
It sleeps from Christmas to Mid February, and no rain falls so no growth in the ground.
A successful hedge.

But in a pot and you do not observe the rest, it will weaken and probably die.
AND you know folk like to trim.
Good Day
Anthony

 

[my nellie]

Cotoneaster are tough itl pull trough!
Sad to hear you lost two tree's

I doubt... Looks like it will be #3

... ...out on your farm, is the soil stony, and if so do you compost.
Yes, the soil on the farm is stony.
We do not compost as we visit the summer residence not too often... unfortunately...

Secondly, I wonder if your cotoneaster has the same situation the fukien tea has down here.
I do not think so but on the other hand bonsai growing in Greece is too young and I am not aware of a fellow bonsaist who has grown cotoneaster...
In fact I am going to ask on our forum and blog in order to be sure.