Help my scorched Juniper.

seanothon

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So, I just noticed that one of my junipers got sun burnt at some point over the past 100 degree days in Cinci. The needles have turned pale green and they are stiff and some are even just falling off. I had been watering it every day but I guess it still wasn't enough. I gave it a nice long water and moved it out of the sun. Anything else I can do for it?
 

Sekibonsai

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"Anything else I can do for it?"

Not let it see you picking out its replacement? I know we all make that promise but you may have to move on... ;^)



Sounds like you let it go a few days at 0 moisture- or it has been fading slowly and the heat was the final nail- it will just further crisp and die- just keep it in the shade and watch the soil water level- maybe there will be some growth that did not fry that you can rebuild from. But... I doubt it.


If it it not tied into pot you could check roots - my guess is they are cooked- you want to see reddish with white tips but my guess will be black and dead.
 

seanothon

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Aww man that sucks. I kind of figured that would be the case.
 

edprocoat

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Seanothon, this summer has been a real bitch on the weather front. I lost my maple, my barberry looks like its gone too, and my one Thuja died and my other one is almost dead yet it has two small back buds on it so I am hoping it will survive. At least my tropicals are in a happy state as well as most my junipers.

ed
 

0soyoung

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So, I just noticed that one of my junipers got sun burnt at some point over the past 100 degree days in Cinci. The needles have turned pale green and they are stiff and some are even just falling off. I had been watering it every day but I guess it still wasn't enough. I gave it a nice long water and moved it out of the sun. Anything else I can do for it?

Of course you realize that root growth stops around 95F and root death begins in the low 100Fs - right? It might be a good idea to bury the pot so the roots never get hotter than 95F.
 

Vance Wood

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sean f

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We have had temps around the 100's for 3 weeks,and my shimpakus have been loving it.lots of new growth and very thirsty
 

jkd2572

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We had had 70days over 100 last summer. We're talking 107-109. I think roots can survive a little hotter than that?
 

0soyoung

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Could you share the source of this information? I've been growing bonsai for more than a couple of years and this is new to me. Who did the research?

Hover on the link - see the url near the bottom of your browser window; click the link - it takes you to the report on the Warnell School of Forestry site. Google the topic (e.g. temperature limits of root growth) to find more.
 

rockm

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I think the conditions that lead to root death in higher temps are pretty variable. Even though we've had temps well over 100 (110 was the highest reading on the thermometer in my backyard over the last few weeks), root death isn't inevitable. I've got trees that are still pushing new growth (BC, live oak, zelkova and others), and some that have retreated to summer dormancy (cedar elm). My Japanese maples haven't dropped leaves and show no signs of doing so.

Keeping pots out of the sun and hydrated is a key to preventing leaf drop and root death, I think. I've got my live oak in full sun and it hasn't begun to slow down. I cover the pot with an old white beach towel and wet it down in the morning. Even in that awful sun, the pot remains relatively cool.
 

0soyoung

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I cover the pot with an old white beach towel and wet it down in the morning. Even in that awful sun, the pot remains relatively cool.

Another way to keep the root temperatures down - how cool!

I'm curious to know if anybody has ever stuck an electronic 'meat thermometer' probe, say, in their pots to see how hot their roots are? I'd be happy to tell you all about my measurements, but it 'never' gets close to 100F where I live (now).
 

jkd2572

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I water my trees about 5:00 pm. I think it probably helps cool the pots back down.
 

Smoke

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I checked the soil temp in a pot in full sun. This is a Ca. juniper in a large pot. The pot is almost 30 inches long and 7 inches deep. Has about ten gallons of soil in it.

As can be seen in the first shot, the tree is in full sun. The right corner shows the soil in full sun while the back left corner has some shade due to the foliage of the tree itself.

The temp in full sun was 91 degrees, while the soil in the shade was 81 degrees. Only about 16 inches difference in location in the pot while the soil in shade was 10 degrees cooler.

Anyone want to buy some shade cloth?
 

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Smoke

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Oh...and the ambiant temp right now was 92 degrees, so in the sun the soil in the middle was already 1 degree lower than the atmosphere @ 2PM.

I wonder what it will be later this afternoon when it hits 104 @ 5PM?


hmmmm....maybe I should check later....
 
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Smoke

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Not so hot today, only about 99 right now with a smalllllllll breeze.

Checked the pot again. Yea, your reading it correctly. 110 degrees at 5PM.

Next week supposed to be around 108 around here. Wonder how hot it can get in a pot. maybe I will move this tree to some shade???????
 

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jkd2572

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Weather channel said 101. My back yard temp gage said 105 in the shade. Alll
Trees in the the shade this time if day. Will only by houses where the sun sets in the front yard. Wife thinks I'm crazy, but she loves me.
 
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