Need Advice on Collected Elm

[gk11820]

Only practicing bonsai for about 2 years, and this is one of my first “successful” yamadori, successful as in it didn’t die right away.

Collected this elm early last spring and it made it through the summer beautifully. Here is a few pictures from summer.



So now it has started to bud for spring, and I noticed one side looks dead ( could just be late to wake up ) and I need advice as to whether I should repot, or fertilize, or just leave it alone for the season.



The left side seems to be dead, my main concern is just the trees health, I know they are resilient and the left side could be made into a cool deadwood feature, but I’m concerned there may be something else I am doing wrong that someone here may catch. Any and all help please !

If I collected something like this these days I probably would have gone in ground or nursery pot also to let it thrive at first, unfortunately I was even more of a newbie at the time and jumped right into a small pot with mostly inorganic soil.

 

[Shibui]

As it made it through last summer it is unlikely to be your collection or cultivation that's caused the dead section. More likely to be from winter. It is not unusual for elms to suddenly lose entire branches. Could be cold, could be root problems on one side, too much water, too little water, borers, etc.
You can often pick dead branches because the bark is a little more wrinkled but I'd give it a few more weeks to see if that branch is just a bit slow before getting drastic with dead wood features.

 

[gk11820]

As it made it through last summer it is unlikely to be your collection or cultivation that's caused the dead section. More likely to be from winter. It is not unusual for elms to suddenly lose entire branches. Could be cold, could be root problems on one side, too much water, too little water, borers, etc.
You can often pick dead branches because the bark is a little more wrinkled but I'd give it a few more weeks to see if that branch is just a bit slow before getting drastic with dead wood features.

Thanks for the reply, I will definitely wait a little. Any advice on how I can narrow down what it might have been ? We did have a cold dry winter here, barely an inch of snow and no snow that really accumulated on the ground. Wasn’t sure if I should’ve out there watering. Could I lift the tree and check the roots without causing too much damage ?

 

[Eckhoffw]

I hope your tree is healthy!
Onthe bright side, losing the left branch (sub trunk) might improve the design.

 

[Shibui]

Could I lift the tree and check the roots without causing too much damage ?

It appears to be an ideal stage to repot so no problem lifting it out to check the roots. Even if all the soil falls off or a few roots break off that tree should recover just fine when you pop it back in the pot.

Any advice on how I can narrow down what it might have been ?

Not really. Results are the same for a variety of problems. You can only make guesses based on the history as you know it.