I’m new to bonsai too but I’ll attempt to answer anyway.
So the point of misting right now is to let the juniper have a drink from the foliage. Transplanted junipers ( in particular) can have difficulty adjusting to new soil /repotting. After transplant giving it foliage water helps ensure the tree gets enough water while it’s roots may be unable to absorb enough water until it adjusts. Keep it in the shade until it adjusts to repotting. You’ll know by any new growth , lack of brown needling and just an overall healthy looking tree. Then slowly start giving it some direct sun light each day.
IMO, a newly collected tree shouldn’t be directly reportted into bonsai soil this time of year. I’m being more cautious and keeping my newly purchased juniper nursery stock slip potted up a size into some potting soil with bark. Keeping most of the old soil on the tree and gently loosening some of the pot bound roots from the edges. Perhaps I could have been more aggressive but why risk it?
I would keep the collected tree in as much original soil as you can and then fill in with bonsai soil or potting mix and sand.
When you mist for humidity you want to spray the entire surface of the leaves as best as you can on the finest mist you have. The smaller the drops of water the faster and better it will humidify the air around it. If you keep spraying, the drops combine to make bigger drops and it defeats the purpose of a fine mist.
You can’t overdo it except if you are spraying so much so often that you are saturating your soil constantly, Day after day and never letting a tree dry out at all. There’s no need to do it to the point of dripping, or 5 times a day even. 2-4 times of several sprays directed over the foliage should be fine. Spray all you want though right now since this may be the main way that your tree is hydrating itself, being newly transplanted.
Otherwise, if you go to mist and it’s still wet, you could probably ease off on the misting.
Here in Ohio I wouldn’t concern myself with misting the tree at night because of the high humidity levels. But a few times throughout the day for the first 3-6 weeks will help your tree through it’s transplant shock.
I know you said your tree was happy, not in so many words did it tell you.. lol
But they certainly do speak to us don’t they?!? We know what our looked like last night and no w this morning...it doesn’t look quite as good, it’s droopy, it’s dry, it’s not as green whatever. Paying attention to these subtle changes and reacting to them is key to having the healthiest trees we can. It doesn’t mean some won’t die but t it does mean they are less likely to. We will quickly identify what our mistakes were and what changes occurred that may have brought on the change in our tree. Fewer possibilities via elimination will be there to explore allowing quicker reactions.
My blue star juniper didn’t look so great right after I slip potted it. But about 5 days later it took a turn.. for the better! It’s been 2 weeks now and it’s full of vigor. New growth, stronger stems. The whole tree looks like it took a big breath and it’s bouncing with new needles and they’re all bushy full.
So I noticed with our hot days, it likes more water, it appreciates being in the sun with some dappled midday shade and looks particularly happy with the fertilizer I gave it a few days ago. It’s rocking! Whew... I’m relieved, did something right at least for now with this tree. As much as it want to start hard pruning it into shape, I’ve limited myself to taking a couple low small branches and dead needles off of it. I pruned one lower branch, that I actually plan on cutting this fall and that’s it for now. Since it’s vigor is in it’s needles.
I would expect your yamadori to take much longer to rebound though. Maybe even 2 months or more. The heat isn’t going to help it, it’s supposed to cool down to the 80’s in Ohio this week hopefully you’ll get a big break from the heat too.
Definitely keeping it in the shade for at least 2 weeks then very slowly only when it’s doing ok start letting it have some direct sun. Then go ask it how it handled that sun before you give it anymore.
I want to see a pic of your tree!
And she thought yours was too long!!! Sorry. I could go on and on....
