Cryptomeria Globosa Nana - odd yellowing

[gavinlg]

Hey all,

I bought this Cryptomeria Globosa from a nursery a month or so ago, full well accepting it may have some issues. When I got it, it was 3/4 the way through winter here in QLD Australia (1-5 degree C nights and 10-20 degree C days), and it had some yellowing around the top of the tree. The lower half and inside of the foliage was healthy and green looking.

I thought I would put it in full sun and water properly and see how it goes. Now about a month later it hasn't seemed to have changed at all, possibly the lower foliage is looking a little less green now.

For the moment, I've taken him out of full sun and into a dappled shade area, and I'm considering trying a copper type fungicide just in case it's a blight of some sort.
Does anyone have any suggestion or ideas of how to get this guy looking vibrant again?

Photos 1 + 2 were from a month ago when I first brought him home, photos 3 + 4 are from today.

 

[sorce]

Looks seperated enough to seperate it fully!

Welcome to Crazy!

Sorce

 

[Bonsai Nut]

Because the damage is localized, it might be that some of the roots are struggling, particularly if the apex roots are on the outside of the rootball and dry out more quickly(?) I would start by checking the roots and see what they look like. I think the damage looks too localized to be insects or disease.

 

[gavinlg]

Because the damage is localized, it might be that some of the roots are struggling, particularly if the apex roots are on the outside of the rootball and dry out more quickly(?) I would start by checking the roots and see what they look like. I think the damage looks too localized to be insects or disease.

Indeed, and that was my initial thought as well. Would you say I should I just pull it gently from the nursery pot and check the visible outer roots of the rootball?

A part of me is tempted to remove the struggling upper cone of foliage, and then do a minimal root prune and repot it into some free draining aggregate, but I'm hesitant perform such a big operation on a potentially sick tree.