How do your temperate climate bonsai cope with that heat?

[Underdog]

This is my first year w/my new "tree house" and I am amazed at what a difference it has made. I always thought more sun the better as long as you water enough but, not so.

 

[GGB]

When I first got into this hobby I was paranoid about my trees being cold hardy. After a few years I realized it was actually the summer heat that I needed to plan around. I use full shade for the day if temps get hot here, but we don't quite see triple digit days like some places. Regardless no Northern species for me anymore

 

[Maiden69]

I only have 2 JM, one cork bark and a koto hime, they are both doing fairly ok this year as they are located under the shade of my yoshino cherry, trident maple and peach trees.

I don't know if the trident, cherry, or peach would be considered a temperate tree, but those are doing great under full sun. Maybe a few edges dried up on the trident, but none on the cherry or the peach tree.

On the other hand I did tried a Mugo pine, that one dried out no matter what I did. Lasted almost 2 years since I received it. I am building an area with shade cloth for next season, as I plan on propagating a few trees, and definitely want to get more JM cultivars.

Cork JM



Koto hime



The vine maple in the far right was left out under a bench and did received a little too much sun... I hope it recovers.

 

[Clicio]

Japanese white pines don't do so well here, not enough dormancy period and the heat just kill them. There are some that keep them alive tho with freezer setups, but for me that's too much of a investment. Some japanese maples can survive here, just need some decent shade netting and up the watering

Yes, South Africa and São Paulo have a similar climate; definitely no Japanese White Pine, and Maples only with the utmost care. Mine are under shade all year round, and get watered and misted twice a day.
The JWP freezer setup is very expensive and too complicated. It's not just throwing them into the freezer; temperature and light both have to be lowered on a day to day basis in the autumn, and slowly heightened in the Spring.