I agree with Jean - a perfectly normal reaction to a stressful weather situation. While Japanese maples are pretty easy to grow and do not usually have a lot of problems, growing them in SoCal can be a challenging undertaking. That is a climate they are not overly fond of. I'd only recommend them for coastal communities, with adequate protection from intense afternoon sun and out of heavy winds (ie, Santa Ana's). And watch out for alkaline irrigation water and compensate for this appropriately. Other than attending to these issues, for your own sanity, don't sweat the small stuff :-) The loss of a few leaves, a little insect activity is NBD. If a LOT of crisping or leaf loss and you see major leaf damage from insects, then you can start getting a little concerned.

You can pot up in mid to late fall if you like, as the leaves drop. I am not familiar with the soil mix you refer to but as long as it is very barky and textural, it should be OK. The trees are a little young to go untended outdoors all winter unless in a very mild winter climate. You don't want to keep them indoors but they should be kept somewhere that stays just above freezing. As to 'maintaining their shape", the Red Filigree will naturally attain an umbrella shape but unless you want that umbrella to form very low to the ground, I'd consider staking the tree upright for a season or so. Just until the main stem (future trunk) attains a more upright habit and a somewhat taller stature. The MY has its own unique form and I wouldn't do anything to it. It will slowly elongate and develop additional stems/short branches with those dense clusters of leaves. The mature form of that cultivar is rather stubby and asymmetrical and your baby is clearly showing those characteristics. IMO, both trees are too young to be planted outdoors any time soon. Those look only like 1 year grafts and I'd prefer to have them grow on in containers where I could monitor them closely for at last a couple more growing seasons before planting inground.

Yellow to orange to red... hmm no wonder why i see all these colors of this maple in the pictures I found. And I did not know there was a Japanese maple whose main attribute is NOT its fall color! I guess thats not the only thing about Japanese maples overall. Btw, do you know if there are any Japanese maples that has fall colors that turn only to orange? I know the green laceleaf varieties do but I'm looking for an upright version.

So sorry about not getting to your message sooner. It's repotting season and I'm really behind in answering Houzz mail. Did you mention where you live? I asked because care instructions are influenced by geography. A developing Acer p 'Mikawa yatsubusa' - image snapped minutes ago. It's raining, if you can't tell. The tree was about pencil thick when I acquired it. I gave it about 2 years of unrestrained (no pruning) growth in the training pot and first styled it in spring of '15. Generally speaking, what your maple looks like now is unimportant (answer to did I pick good trees) because only a tiny fraction of the mass you purchased will be a part of your bonsai. You choose deciduous and tropical broadleaf trees based on how their roots look. Having some very low branches is a big plus in some species that don't back-bud reliably. The trees you chose are in some respects easy because both practically get buds ON beds. IOW, they're prolific back-budders on not too old wood. The maple's branches get stiff and hard to wire very quickly, and the tree fattens quickly, so wire can't stay on the tree too long. Develop the maple from the bottom up. Let the lower branches thicken and ramify by restraining the top. Your tree will likely be made using only the first pair of branches above the soil, so treat the entire top above those branches as a sacrifice branch. It looks like there is one thick branch with a newly formed branch opposite (first pair of branches). What I would do: I would cut several branches off above the first pair so the first pair gets plenty of sunlight. Like this: Other than removing the branches just above the first pair to get light to your developing tree. you don't care about the top because it's coming off at some point. Prune the heavy branch moving to the right in the first image back to 1 pair of leaves. This should force buds to pop close to the trunk. The closest bud to the trunk that breaks on the fat branch will be the tree's temporary top/leader, so train it in the direction you want it to grow while it's very young. You won't likely have any success trying to grow your trees indoors. Re the Chamaecyparis: The entire top of the tree will go away when you chop it. Your tree is in the branches just inches from the soil line. Again, I would prune ALL branches that shade that small cluster of branches at the bottom. Wait for one of the low branches to prove it's vigor and remove the rest of the low branches. The branch you choose will be the part you develop into your tree. Ideally, you would find an experienced bonsai practitioner who is willing to look at the roots and suggest where the 'front of your tree should be and develop it accordingly. Roots are a very important part of your composition. In time, if you stick with bonsai, you'll find yourself grafting roots and branches to trees you want to keep in your collection; this, in order to improve their eye appeal. I hope what I said made sense to you? Al