I'm coming to the conclusion that "full sun" means "Full sun.....but..."

[Mike Corazzi]

...........Full sunny BRIGHTNESS.....

I have "rescued" junipers by moving to the "sun bench." Olives too.
HOW-EV-ER our sudden onslaught of summer has made heat QUICKLY!
And.... I can see some reaction even in junipers and olives.

BEGINNING to look crisp-ISH (a bit) olives taking on some waviness. Not right. A few juni tips not laughing at their private juni-jokes.

Soooooooooooooo..... "FULL SUN" here in Corazziland is gonna mean .....UP TO..... 90 degrees.

........................Fair-in-height

 

[Atom#28]

...........Full sunny BRIGHTNESS.....

I have "rescued" junipers by moving to the "sun bench." Olives too.
HOW-EV-ER our sudden onslaught of summer has made heat QUICKLY!
And.... I can see some reaction even in junipers and olives.

BEGINNING to look crisp-ISH (a bit) olives taking on some waviness. Not right. A few juni tips not laughing at their private juni-jokes.

Soooooooooooooo..... "FULL SUN" here in Corazziland is gonna mean .....UP TO..... 90 degrees.

........................Fair-in-height

Same stuff going on in my backyard. 92f on Tuesday, 95f yesterday, and 93f today. Elms and spruce and even my larch are happy AF, but junipers look a bit “parched” and hinokis do too.

 

[RKatzin]

Water! Water! Water! When the heat steps up you have to step up the water.

 

[Mike Corazzi]

Water! Water! Water! When the heat steps up you have to step up the water.

To a rolling boil or just simmer?

 

[Mike Corazzi]

Seriously, the trees will only take so much water on VERY hot days. It isn't being used and it doesn't do what water should do.
Now spraying to COOL the whole tree (bark and all) that's ok.
But more water just turns to stew.

 

[Paradox]

Water! Water! Water! When the heat steps up you have to step up the water.

This.
When it gets really hot here, I water twice a day instead of once

Your juniper are getting crispy because they don't have enough water

 

[RKatzin]

Seriously, the trees will only take so much water on VERY hot days. It isn't being used and it doesn't do what water should do.
Now spraying to COOL the whole tree (bark and all) that's ok.
But more water just turns to stew.

Sounds like a soil composition problem. What's in your pots?
I'm in predominantly pumice. The few additives are barely worth mentioning, but even the things I'm growing out have a lot of organic but still pretty much flow through drainage. I can stand at any one of my pots with the hose on full shower and the pot will not fill up and over flow.
Roughly: less than 80° I water every two or three days. Over 80° and I water once every day. 90° and above I water twice a day, once in the morning and once in the early afternoon. Maybe a third if the wind is up along with the temps.

 

[BrianBay9]

When people east of the Mississippi say "full sun", they might mean 25% shade cloth in the west. There is so little humidity in the air where you are, the "full sun" is more intense than anything in the east.

 

[Dragon60]

Well it does get very hot and humid in Florida, but large trees in the back yard provide a lot of partial shade.

 

[Mike Corazzi]

Sounds like a soil composition problem. What's in your pots?
I'm in predominantly pumice. The few additives are barely worth mentioning, but even the things I'm growing out have a lot of organic but still pretty much flow through drainage. I can stand at any one of my pots with the hose on full shower and the pot will not fill up and over flow.
Roughly: less than 80° I water every two or three days. Over 80° and I water once every day. 90° and above I water twice a day, once in the morning and once in the early afternoon. Maybe a third if the wind is up along with the temps.

I think you're right. EVERY time I decide to "be good" and use akadama... EVEN AS ONLY PART OF A..MIX...., I have problems. The boxwood I rescued with 100% pumice is humming along happily.
I went with larger pots this year for "stability." And to maybe not have to RE POT next year.
Looks like I fucked up.

Even watering as I do.....which is "as needed" I am not getting it ....right. And yes, twice a day (at least) during our forged in fire days.

 

[badatusernames]

Seriously, the trees will only take so much water on VERY hot days. It isn't being used and it doesn't do what water should do.
Now spraying to COOL the whole tree (bark and all) that's ok.
But more water just turns to stew.

Does this not cook the leaves? I thought part of spraying pesticides in the AM was due to the leaf opening, but also partly due to avoid getting things scorched when under intense heat. I feel like I've also heard that whether or not this is true may or may not be a bit of an age old debate but I'm not positive, so sorry if I'm opening a can of worms.

 

[AZbonsai]

BEGINNING to look crisp-ISH

They do much better if they have time to acclimate to the full sun. I do not even think about shading my bonsai until we have a week of 100+. I will have bald cypress on the full sun bench today at 105.

 

[Mike Corazzi]

Does this not cook the leaves? I thought part of spraying pesticides in the AM was due to the leaf opening, but also partly due to avoid getting things scorched when under intense heat. I feel like I've also heard that whether or not this is true may or may not be a bit of an age old debate but I'm not positive, so sorry if I'm opening a can of worms.

I spray ONLY the trunk. And add some water to the soil if needed.
Not ...mist... spray with water from the nozzle.

 

[Mike Corazzi]

They do much better if they have time to acclimate to the full sun. I do not even think about shading my bonsai until we have a week of 100+. I will have bald cypress on the full sun bench today at 105.

Bingo. Same here.. They were in sun from bud break to now. It's the sudden RUSH of heat that gets em.
This year went from 70s to 90-100s in a couple weeks.

 

[penumbra]

Does this not cook the leaves? I thought part of spraying pesticides in the AM was due to the leaf opening, but also partly due to avoid getting things scorched when under intense heat. I feel like I've also heard that whether or not this is true may or may not be a bit of an age old debate but I'm not positive, so sorry if I'm opening a can of worms.

This is true because pesticides can be very reactive to heat. Water on the leaves does not cause scorch. This has been debunked several times, most recently in Bonsai Heresy.

 

[AZbonsai]

RUSH of heat

BINGO

 

[Moridin]

I'm in the same boat as you @Mike Corazzi this bomb of a heatwave we are having hit hard


I'm in orangevale and a couple of my maples got slightly crispy this week with the weather we are having. Even though they are in a somewhat shady part of my backyard.

 

[AZbonsai]

Now spraying to COOL the whole tree (bark and all) that's ok.

Hey Mike check your bonsai pot temps. Roots stop working in extreme heat. I cover my pots with burlap to keep the sun off. Bonus: water on the burlap creates evaporative cooling effect. Burlap also dries out so you do not have to worry as much about fungal issues. Just my two cents.

 

[Mike Corazzi]

Hey Mike check your bonsai pot temps. Roots stop working in extreme heat. I cover my pots with burlap to keep the sun off. Bonus: water on the burlap creates evaporative cooling effect. Burlap also dries out so you do not have to worry as much about fungal issues. Just my two cents.

Good idea. I hose off the pots when I cool the trees.
Has been less concern since I went to plastic.

 

[Shibui]

Learning how to water properly makes a big difference to how much heat and sun the trees can tolerate but with each species there seems to be an upper limit that watering cannot overcome.
We recognize that maples are less sun hardy than pines.
Even among conifers I find that shimpaku does better with some shade in the hottest months.

When people east of the Mississippi say "full sun", they might mean 25% shade cloth in the west. There is so little humidity in the air where you are, the "full sun" is more intense than anything in the east.

Very true. 'Hot' depends on what we get used to. Hot for us also depends on humidity so humid zones feel hotter but seems to be less stressful on plants.

It regularly gets over 40C (100F) here in summer and that's a dry heat like US west. I put up 30% shade over susceptible trees - usually after Christmas here (mid summer) when daytime temps are approaching 40C for more than just a day at a time. The shade stays there until it is much cooler in autumn.
Taking shade away too early exposes shade adjusted leaves to full sun too quick and they will burn even in moderate temps so the shade has to stay on even when temps reduce to less than spring.

I did trial less shade just to see if I could do it. More water goes a long way to compensating but it is hard to get it exactly right and trees are still under stress so don't grow well. I managed to get maples through summer without shade but they did have some burnt leaves. Much easier to add some shade when required.