AusBonsai

Hello guys,

I'm very new to bonsai and taking care of maples so I'm quite unsure of what's happening here. I bought this maple as a bare root tree during winter, but potted it immediately. However, although it's now spring, it hasn't come back to life yet. I also noticed today that there's some discolouration in the trunk close to the soil, shown in the image attached. I scratched it a bit and found that it's already brown compared to the neighbouring regions (still green). Is this maple going to be okay?
Thank you so much for the help.

Cheers

Unfortunately, the black bark down near soil level is not a good sign. It indicates some sort of fungal infection. I have never positively identified the disease but it is usually fatal and it's way too late for any treatment when it reaches the stage shown here.
It seems to be something that particularly affects Japanese maples and seems to be a problem where Japanese maples stay too wet through winter and Spring.
The only time I have managed to save one was when I noticed the first sign of black on the bark and then put the pot up on a wire bench and kept it relatively dry.
The 'scratch test' is often advised but, it does not tell us much. It can identify dead areas but, by then it is too late for action. Areas that still show green may already be dying but not quite changed to brown - again, too late for treatment. The lack of growth and black bark have already told you these things. All that the scratch test does is open possible healthy trunk to further infection. take my advice - DON"T DO IT.

You could try a fungicide treatment on your maple and keep it for a few more weeks to see if it might still have some life and come good but I sincerely doubt it will. Does not look like an expensive tree so I would BIN tree, soil and pot now to reduce chances of this spreading to any others. Make sure you are not overwatering any other trees you have. Then, look for a replacement tree for your bonsai journey.

BTW, As a beginner you would be much better trying a trident maple instead of JM. I know JM has Japanese in the name but tridents are so much easier and will give you almost all the great features of a Japanese maple with way less problems. Go to any bonsai show and count up the numbers of good Japanese maples then count up the number of good trident maples on show. Even in Japan, really good trident maples are much more common than great JM. The numbers will quickly show how much easier tridents are.