In seaching thru this site, I don't see any other threads on zelkova.  Any particular reason for that? 

A zelkova killed my goldfish.  I don't like to talk about it.

I've only got seedlings myself.  There's a local guy here that has trunks about that size, but gnarly scars and warts all over.  He's one that plants in the ground and forgets about them for decades.  Little to no work done on them in the ground produces inferior "trunks", let alone good bonsai.

Yours on the other hand looks like it has some promise. 

Judy,

Isn't it interesting how people get started in Bonsai?  I saw my first bonsai at the Dogwood Arts Festival in Piedmont Park in Atlanta, GA in 1975.  It was a trident maple shohin with incredible taper.  Since then, I have always like tree with taper.

I started researching bonsai, and one of the first books I got was a publication by the Brooklyn Botanical Society, that had translated articles on bonsai.  One of those was about zelkova, and how to start them from seed, and how they progresse over the years.  Since then, I've always wanted a decent broom style, and have never found one, until now.  I tried growing some from seed, and found that maybe 1 of 20 had any potential.

But I digress...

This tree has decent nebari.  Whoever started this tree had a clue.  I don't know why they let it go.  The provenance that I know of is that the local shop aquired it along with dozens of other trees, mixed varieties.  Only a few were zelkova.  They came from someone who was liquidating a "collection", originally from California.

I have not done anything to the tree, waiting for spring.  It was leafless when I purchased it.  The big clumps of moss will go.  I will really inspect the nebari when I repot in a month or so.  I'm not crazy about the white pot, I  may change it to a dark green/gray.

Nice one Judy!

Adair, may I recommend removing the moss now as to prevent any damage/rotting of the trunk.   And I also think this tree has great potential.  Good Luck!
Chris

Is it actually a Zelkova Serrata?

Looks more like a Chinese elm to me - and certainly in Europe, Chinese Elms are marketed as Zelkova Parviflora. I have 50 or more of these.

I went ahead and removed the moss to get a good look at the nebari.  It looks very good to me.  I'm thinking that this tree might have been an airlayer since the roots are fairly thin and consistent around the trunk.  Most seedlings, if not carefully tended to when they are young, will develop heavy taproots.

I've attached photos.

Even though we're having warm weather, the early daffodils are blooming, and my red maple trees in the front yard have flower buds swelling (some blooming) the zelkova's buds were tightly closed. I'm thinking the best time to repot is just when they are swelling?

Indeed.

I did start removing the crossing branches, and doing some trimming back. 

And I did think it needed a wider, shallower, pot.

I've attached a photo of one I think might do.

John,

I have some really thin, wide pots.  I used to use them for making forests.  Would something like that do better?