Acer palmatum in "hot" weather ?

Jan JC

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Hey everyone!
First of all, I'd like to apologize if my english isn't correct, I'm from Spain so it's not my maternal language...
Anyway, I have a Japanese Maple (actually two of them), varieties are 'Seiryu' and 'Yamamomiji' (common Japanese Maple), since this spring-summer (2020).
They've been quite ok, none of the leaf tips has been burned a lot, just the beginning of the tips of some leafs...and only on the 'Yamamomiji', 'Seiryu' was great.
So, the question is, is my weather ok for them to properly grow in here? By the moment they are ok but..I'm not sure...
Winters temperatures are generally 5°C min and 15°C max, sometimes a bit colder, reaching 0 to 2°C some very cold winter mornings.
Summer temps are 23°C min and 33°C max, sometimes reaching 36°C in hotter days (maybe a week per year)
Direct sunlight isn't quite abundant, cause I think it isn't good for them...
Is everything correct ? What do you think?
Thank you very much!
 

Jan JC

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Hey everyone!
First of all, I'd like to apologize if my english isn't correct, I'm from Spain so it's not my maternal language...
Anyway, I have a Japanese Maple (actually two of them), varieties are 'Seiryu' and 'Yamamomiji' (common Japanese Maple), since this spring-summer (2020).
They've been quite ok, none of the leaf tips has been burned a lot, just the beginning of the tips of some leafs...and only on the 'Yamamomiji', 'Seiryu' was great.
So, the question is, is my weather ok for them to properly grow in here? By the moment they are ok but..I'm not sure...
Winters temperatures are generally 5°C min and 15°C max, sometimes a bit colder, reaching 0 to 2°C some very cold winter mornings.
Summer temps are 23°C min and 33°C max, sometimes reaching 36°C in hotter days (maybe a week per year)
Direct sunlight isn't quite abundant, cause I think it isn't good for them...
Is everything correct ? What do you think?
Thank you very much!
I forgot to say I'm in Barcelona!
 

JoeR

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I think the most important thing to pay attention to if you're worried about heat is the pot. Ensure that the container the maples are growing in are not baking in the sun- if you keep the roots cool they should be just fine. This means avoid black pots, use damp sphagnum on the soil surface, plastic or tinfoil to block light, etc. Your English is great by the way!
 

Jan JC

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I think the most important thing to pay attention to if you're worried about heat is the pot. Ensure that the container the maples are growing in are not baking in the sun- if you keep the roots cool they should be just fine. This means avoid black pots, use damp sphagnum on the soil surface, plastic or tinfoil to block light, etc. Your English is great by the way!
The pot isn't heated by the sun, and over the soil there's a bit of pine ...corch ? ...bark? (sorry idk the english name...)to keep it humid.
Then everything is fine?
Thanks!
 

clem

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i grow my JM in a ventilated green house and the T° can reach 50°C during heat waves. In summer T° is usually 40 - 45°C inside the greenhouse and the JM and other decidous grow very well with no sign on the leaves.
Before, the leaves extremity of my JM used to be burned, but the problem was a lack of watering. I used to water every 2 days, but now, i water every day and the leaves are fine.
So i think your leaves burns are more probably caused by a lack of water and/or wind. JM hate wind !
The 1rst signs of excessive T° and sunlight are some little black spots on the shoots. Now i use a shade sail during summer (july & august) to protect from the sun. And i mist the trees frequently during heat waves, to lower the T° (from 50°C i have very quickly 47°C after a mist inside the greenhouse )
 
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Jan JC

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Wow, those are hardy maples !
If you can grow them fine, I'll be able too.👍
Why do you grow them in a green house? Are outside temperatures extremely hot/cold??


*Yeah, wind is quite common here, so it may be that what burned my leaf tips.
 

clem

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Wow, those are hardy maples !
If you can grow them fine, I'll be able too.👍
Why do you grow them in a green house? Are outside temperatures extremely hot/cold??


*Yeah, wind is quite common here, so it may be that what burned my leaf tips.
i think they enjoy/support high T° (but i don't affirm it, it's just my feeling) and i live near to the beach, so i have very frequently some wind. Wind and soil drought are the things to avoid with acer palmatum IMO. High T° isn't an issue at all in my place, unless it exceeds 50°C (1mm black spots on the young shoots and after that burns on the leaves if the T° are too high and sun too strong).

In my 3 years of JM experience (which isn't very long i confess) JM prefer 40°C with sun, frequently watering and NO wind, than 30°C and wind

I live in Normandy, so my outside T° are quite mild & temperate. 5- 10°C in winter, 30-40°C maxi in summer. I use a greenhouse to avoid WIND and the birds that damage my organic fertiliser :eek:
 
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Jan JC

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Hmmm I see.
Winter temperatures inside that greenhouse are low , I suppose, right?
I don't remember where I red that A.palmatum need really long cold periods , if not they grow poorly...maybe it was wrong.
I have no experience with Acer palmatum, that's why ask so much😅
 

clem

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Hmmm I see.
Winter temperatures inside that greenhouse are low , I suppose, right?
I don't remember where I red that A.palmatum need really long cold periods , if not they grow poorly...maybe it was wrong.
I have no experience with Acer palmatum, that's why ask so much😅
I have only 3 years experience with JM so it isn't a long experience neither ^^
In winter, the T° inside the greenhouse are frequently the same as the T° outside, because the weather is cloudy 80% of the time in my place, so no sun ray and no "greenhouse effect". With sun, the inside T° is maybe 15-20°C maxi during a few hours, when the outside T° is 10°C. I don't plan to change my way of cultivating, because in my situation, in my greenhouse, it works very well : the trees grow well and they have no sign of disease or "early bud break" up to now...
 

Maiden69

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Bienvenido. Another place you can check on in our language is David Cortizas website . He is also on YouTube under "Escuela de Bonsai Online", he is located in Cadiz, which is a 10b zone just like Barcelona. Spain growing zones. David opened his forum again, you could send him a PM there or check for other españoles that are growing a.palmatum there. I know he has quite a few, but from what he explains in addition to the lack of "chill" hours, they don't like the Spaniards sun at all... so you will at least need to get them protection from the afternoon sun.
 

Jan JC

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Bienvenido. Another place you can check on in our language is David Cortizas website . He is also on YouTube under "Escuela de Bonsai Online", he is located in Cadiz, which is a 10b zone just like Barcelona. Spain growing zones. David opened his forum again, you could send him a PM there or check for other españoles that are growing a.palmatum there. I know he has quite a few, but from what he explains in addition to the lack of "chill" hours, they don't like the Spaniards sun at all... so you will at least need to get them protection from the afternoon sun.
Hola!
Yes, I know his forum, but I remember it was very inactive, and after all polemics and the temporary closure...I decided to move to another forum , as this one is in english I suppose I'll get more accurate info as more people speak it.
Anyway, thanks for the suggestion!
(no se porqué te hablo en inglés si seguramente me entiendas....😂)
 

Maiden69

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Hola!
Yes, I know his forum, but I remember it was very inactive, and after all polemics and the temporary closure...I decided to move to another forum , as this one is in english I suppose I'll get more accurate info as more people speak it.
Anyway, thanks for the suggestion!
(no se porqué te hablo en inglés si seguramente me entiendas....😂)
Si... but to be polite and have everyone included in the conversation.

HIs forum was inactive for a few months. I think he is still working on migrating the old content into the new forum... David is awesome, but he is not good at ignoring the negativity that a few people project. I guess it is the same in almost every forum... I moderate at a luthier website, and a lot of times, you get a lot of negative comments when you post something that is not the "norm", even if the end result is the same, or better than what others achieve going the "tried and true" way.

It is true that there is way more information here, because of the "universal" language, but even here, a lot of the more seasoned members will tell you to go search out local talent in order to get information on what works and what doesn't in your area.
 

Kanorin

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I agree with the above advice to ask people local to your climate. I don't think too much heat will be an issue as long as you give them some sun and wind protection and/or can get them enough water. But you might be right on the border of providing enough winter chill time. I notice on a topography map that there are some hills or mountains a little bit inland from Barcelona - you might even be in a situation where they could get enough winter chill time up at higher elevations, but may not at sea level.

I'd ask locals if anyone has kept them healthy for four years or more, because lack of winter chill would manifest as a slow weakening over the period of a few years - perhaps becoming less resistant to insects or disease (from what I have read in Michael Hagedorn's book).
 

Jan JC

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I agree with the above advice to ask people local to your climate. I don't think too much heat will be an issue as long as you give them some sun and wind protection and/or can get them enough water. But you might be right on the border of providing enough winter chill time. I notice on a topography map that there are some hills or mountains a little bit inland from Barcelona - you might even be in a situation where they could get enough winter chill time up at higher elevations, but may not at sea level.

I'd ask locals if anyone has kept them healthy for four years or more, because lack of winter chill would manifest as a slow weakening over the period of a few years - perhaps becoming less resistant to insects or disease (from what I have read in Michael Hagedorn's book).
Yep, next to Barcelona there's a mountainous area called Collserola.
Temperatures just behind there can be far below 0° (-5°C aprox.) meanwhile in Barcelona temperature is around 3°-4°C; and unfortunately I live in the "hot" area...
About what you said refearing to the gradual weakening over the years, I don't think this will happen to mines (I hope 🤞🏻), at least because as Maiden69 said, there's a Spanish Bonsai youtuber called David Cortizas, who lives in a hotter place than I do and has some Acer palmatums; what I don't know about those maples is how do are they, maybe is true that they are weaker than they used to be.
 

Jan JC

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Oh, now I remember that some months ago I saw a palmatum bonsai in Barcelona, as that was ok and was in an exposition(so it's been there for quite a long time), it may be possible to have it here !
This is the bonsai I'm talking about, is beautiful:
IMG_20200726_162742.jpg
 

clem

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Yep, next to Barcelona there's a mountainous area called Collserola.
Temperatures just behind there can be far below 0° (-5°C aprox.) meanwhile in Barcelona temperature is around 3°-4°C; and unfortunately I live in the "hot" area...
About what you said refearing to the gradual weakening over the years, I don't think this will happen to mines (I hope 🤞🏻), at least because as Maiden69 said, there's a Spanish Bonsai youtuber called David Cortizas, who lives in a hotter place than I do and has some Acer palmatums; what I don't know about those maples is how do are they, maybe is true that they are weaker than they used to be.
yes, keep motivation, hope and joy because it is always better to have fun and keep optimistic 👍
When i started to show my JM from cuttings in the french forum i use to show my trees, i recieved those comments : "it will take a very long time before you reach your goal".. or "JM cultivar don"t survive more than 3 years on their own roots" or "I'll follow your topic, i used to cultivate Deshojo JM and it died because of a disease a few years ago".. so many sincere but unintentionally disheartening comments. Keep the motivation, the pleasure to cultivate and the pleasure to contemplate your trees, even if people don't give you the comments you expect !!
As Sorce said : welcome to crazy ! (i think it is the meaning of his sentence : enjoy )
 

Jan JC

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yes, keep motivation, hope and joy because it is always better to have fun and keep optimistic 👍
When i started to show my JM from cuttings in the french forum i use to show my trees, i recieved those comments : "it will take a very long time before you reach your goal".. or "JM cultivar don"t survive more than 3 years on their own roots" or "I'll follow your topic, i used to cultivate Deshojo JM and it died because of a disease a few years ago".. so many sincere but unintentionally disheartening comments. Keep the motivation, the pleasure to cultivate and the pleasure to contemplate your trees, even if people don't give you the comments you expect !!
As Sorce said : welcome to crazy ! (i think it is the meaning of his sentence : enjoy )
Thanks for the encouragement!
These are my palmatums ( in summer, when they had leafs),as you can see they looked healthy, I hope they keep this look for so many years.This winter-spring I'll repot and turn them into bonsai.
IMG_20200725_131746.jpgIMG_20200917_135531.jpgIMG_20200722_114812.jpg
 

Dav4

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What is your relative humidity like in the summer? A hot AND dry wind during the summer months will definitely damage A. palmatum leaves. Without knowing anything else about your microclimate, I suspect you'll need both sun and wind protection and if truly dry with low humidity, misting during the day will be very helpful
 

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