Help! Shishigashira not leafing out

[Jphipps]

I removed an Acer Palmatum Shishigashira air layer last summer from the parent tree. It formed roots in the sphagnum moss and I potted it in a training pot leaving the sphagnum ball alone and surrounding it with bonsai soil. I left it outside over winter and likely should have done more to protect it.

This spring the buds were looking healthy and some started to barely open up and then everything stopped. I bark is still green underneath and it looks fine otherwise. The parent plant leafed out a few weeks ago.

Anything that can be done to save it? Maybe there aren't enough roots to support it? Treat it like a cutting? Humidity bag?

Looking for advice as I don't think this one has much of a chance at this point.

Thank you!

 

[Jphipps]

Buds just hanging out.

 

[Shibui]

Check the base of the trunk for black bark. There is an infection that kills the roots of JM in particular and only shows up when the buds open. Most obvious symptom is dead black bark near soil level. Much more prevalent when the roots are wet and cold. It is possible the sphagnum kept it way too wet over winter and spring.