Good evening everyone,
Tomorrow is going to be 36C (96.8F) and Friday is 42C (107.6F) just wondering what extra things i need to be doing in this heat? Obviously more watering but is there anything else?
Cheers.
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What species are you working with? No trees in north America like temps above 100F. Some junipers thrive in heat, most deciduous do not. Shade cloth can both reduce radiation as well as heat. If the pot overheats the roots may die and lose the tree. Shading or wrapping the pot with burlap or towel can protect from overheating. A wet bench and moist cloth wrapping can help keep the pots cooler from evaporation. If you have a shaded area the trees can be moved until the heat wave is over.
Where do you live?
Good luck and let us know how it went.
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Hey Jimmy, you’ve got to be kidding me. Did you do that on purpose? don’t rub it in man! We’re around -20C in Montreal. Here’s what else you should be doing: Have a beer, enjoy the heat. Laugh at us folk frozen in the northern hemisphere… also maybe water the surfaces around the trees and the pots too to cool them down.
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As soon as my temps hit that high, I move them into some shade. Even junipers appreciate shade after some morning sun. In a bonsai pot, even sun loving trees need a break from the sun in those temps.
Keep them watered, but not wet. I water in the evenings when it’s cooler, and the water doesn’t evaporate as fast, but I check them in the morning and mid day when I can, to make sure they aren’t drying out. If you aren’t used to it, you’ll really have to watch your watering until you figure out what your trees need. And skip the fertilizer if you can. Good luck!
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Thanks for the responses.
In regards to species I have some Japanese maples, Chinese elms, ficus Benjamina, juvenile shimpaku juniper, as well as a few Australian natives (mostly eucalypts but also melelueca).
The maples are in a good spot where they will get a little morning sun but then shade. The natives are all in full sun, and I’m watering morning and night. The Chinese elms and Junipers have been moved to the maples. I’m just not sure about ficus.
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I keep a green island ficus and several ficus benjamina in shade after getting morning sun until 12 noon, and they do great. I also keep some tiger bark ficus in a completely shaded porch, because they can’t take my summer sun, even for a few hours. I keep one pre-bonsai benjamina in almost full sun, and though some leaves drop in the summer, the tree does fine the rest of the year. Ficus are very resilient.
I would tell you to move it to a spot where it will get a break from the afternoon sun, and watch the watering. Out of all my trees, bougies and junipers included, ficus are the ones that handle my heat (117°F average in the summer) the best. As long as you mind the watering!
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Always an option to keep the ficus inside during heat spell. They do well indoors with adequate light water and air circulation. Mine live in the 3 season room during the winter with florescent lighting to increase daytime sunlight condition. Unless the heat inside is greater than outside!! lol 
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Jimmy I’m guessing you’re in Australia. Most figs can deal with the extended heat, even when they’re getting radiated heat from surrounds, as long as you can water them deeply once a day. I think your ideas of moving the other trees into the shaded areas will be a good one for the duration of the extreme heatwave. I’ve heard of a few South Australians getting crispy plants because of the repeated days of over 45°.
You can get plenty of localised info on ausbonsai.com.au
I’m in Brisbane, and usually set up shade cloth enclosures for the Summer.
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Yeah in Melbourne. We aren’t having weather quite as harsh as Adelaide but it’s still been hot.
I’ve found the Spring fundamentals video but haven’t been able to find a summer one, that might be because I haven’t quite figured out the best ways to navigate the library though.
The plants seem to be holding on well though so for now I guess I’ll just keep doing what I’m doing.
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Hmm there used to be a filter for the fundamental series, but I don’t seem to see it now.
Anyway, most of those were released for free on YouTube too, and maybe it’ll make it easier to find it there.
I think the one you’ll want is Post-Growth Management. But I don’t remember if it’ll address your standing question of heat management (maybe a little here or there)
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Good luck with it, the heat will be a constant in Summer for the future, by the looks. I only have a suburban block, so my trees are constantly moved to either catch the sun or dodge it, and I suspect that’ll be what you’ll need to do as well, especially when there is a heatwave.
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@MelBAU
Do you have any native trees? I tried a eucalyptus once, hard to train and did not like wire. Succombed to my ignorance of the species…? Seems they would be more heat and draught tollerent…?
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Hi Kurt
Many of the Eucalyptus, Callistemon and Melaleuca actually seem to like sitting in a shallow water tray during Summer, strangely enough. You’d think they’d be drought tolerant, but I guess because we cut their tap roots off, they can’t go chasing deep water underground. I’ve even read that sitting them in water after repotting is a good move, which generally goes against the standard you expect from exotic trees…
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The summer heat is finally here. Going to hit 94F not including heat index. With the heat index it’ll be over 100F for sure. My trees have shut down. I haven’t had to water most of them for two days.
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Seemed prudent to add the link above incase others find the thread in the future. It’s got some good tips in it as well as identifying the damage.
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