Japanese black pine (shohin?) restoration

I "found" this tree last year (march 2014) with a bonsai guy that was downsizing his collection. The color was pale, small buds and there were no backbuds visible. It was in a small pot (little smaller than the one on the first pics) and drainage wasn't good.
Repotted march 2014 in a bigger pot, removed dead roots and a bit of the old soil from the outside. Left the core (compacted akadama and old potting soil).

Old pictures from 2010
Just before repotting i wired everything "open" and selected some branches. The branch stubs "jins" where weak and they were not in the right places so removed them all. The main trunk was hollow almost to the root base. I filled it with 2 compound filling. I would like it to close in the next 5 years. The branch on the right is a bag branch, i brought it in this position because when the tree wants to make a bud on the right place i would like to have the tree there. I like the height and the angles there but grafting there on a small tree like this ... i'm not ready for that yet.
Photo January 2015
April 2015. Backbudding all over the place. I guess he likes it here.
The biggest candles now (end may 2015) are 10cm (4 inches). I would like to build the basic structure with some of these.
This is my first JBP. This would be my plan:
-select needles in fall 2015
-Repot in 2016 (clearing the core of old soil, not messing with the exterior new roots) There are 2 big roots that form a hook were they were jammed in the little pot and i don't like them so if possible i would like to reduce or eliminate them over the next years.
-Starting to candle prune in summer 2016.
This is a question for the pine experts here.
Is it better to eliminate the bigger candles now and let the inner buds strengthen? Or do i let these grow (its not bad for those 2 sections to gain some caliber), so the rest of the tree can benefit from the extra power?
Thanks
Dirk

You've done a great job getting this tree healthy again!

There are a lot of back buds popping! Fantastic! Don't touch these at all until next year.

The strong candles can and should be decandled this summer. You have enough back budding going on that there no risk to the tree.

Mid June, cut those strong candles off completely, leaving about 1/8 to 1/4 inch of stub.

Your next repotting should be a "half bare root" repot. Remove 1/2 the old soil under the trunk. Pick a side, and bare root that side. Left or right. Or maybe front or back.

Pick whichever side has the weakest roots and bare root that side. Two years later, bare root the other side.

Wooow nice buds man.

Adair M said:

You've done a great job getting this tree healthy again!

There are a lot of back buds popping! Fantastic! Don't touch these at all until next year.

The strong candles can and should be decandled this summer. You have enough back budding going on that there no risk to the tree.

Mid June, cut those strong candles off completely, leaving about 1/8 to 1/4 inch of stub.

Your next repotting should be a "half bare root" repot. Remove 1/2 the old soil under the trunk. Pick a side, and bare root that side. Left or right. Or maybe front or back.

Pick whichever side has the weakest roots and bare root that side. Two years later, bare root the other side.

Click to expand...

Thanks for the input Adair. I'll cut the candles off soon. I'll see what happens. I've read a lot about half bare rooting. Must try it once. I will update when the time is right.

Really great job, it's going to be fun picking and choosing! You must have done it right. What did you feed this guy?

Dirk, I've done the half bare root repot dozens of times. It's the way to do conifers when you need to get fresh soil under the trunk.

Also important to use it when adapting collected yamadori from the old native soil to bonsai soil.

InSANE amount if back budding on this tree... Almost... Reminds me of an azalea that was cut back hard with billions of new little buds all over it! Crazy... Never seen a Pine do it to this level! Great job!

The amount of backbudding must be from the shock going from 0 care to a lot of it. I feed with TLC, chemical fertilizer from various garden centers and "equilibre", natural compost (also a mix). It's a slow organic fertilizer that you can distribute equal over the soil instead of the bigger balls with less options to distribution. It's now my 8st year in bonsai and tried from no fertilizer to a lot. This year i'm backing of a bit... It's not like this one is back budding like an azalea, there are still some areas where i have to induce them. I have good hopes for the next few years. It will be a challenge to fill this small one with good ramification. Thanks for helping me out and giving some direction.

before... longest shoots size of index finger...

this was cut off...


result after cutting back and wiring. I did some branch selection. Main branches have been chosen. When looking at this picture i got some problems with the balance. Need to tilt it a bit to the right when repotting. Second question. What to do with the apex? Let it go to the right? or keep it to the left?

hand for size

You take this too great pines, thanks for sharing

Realizing how old this is.....

The top most part, I'd bring right as a next right branch and use the lil guy left as new apex.

This is a dope lil tree!

Sorce

Thanks Trunghongmon, and Sorce, it could be a good option. It would be a rather big branch that high up and with a "slow bend". When possible i will use a smaller bud with closer internodes. Sorce, it is not bad to respond on old topics. We talking about bonsai here, we have all the time of the world.

After cutting back, this pine went weak. By september needles where pale green, remembering where it came from i figured overwatering after cutting the candles might be the cause. So i placed it in greenhouse, by that time it barely dried out. In spring after repotting an other pine from the same source (old core) i repotted this one. Not much root growth was seen and i removed almost all old soil, placed it in a wooden box with free draining soil. Color is better, buds are big. 2 steps forward, 1 step back.

Spring 2016 this pine was repotted as stated before. I left it to grow strong in it's "new" growing box. On july 8 the tree was strong enough to take the next cut.

July 8 is on the late side and i helped the pine a bit by putting it in the greenhouse from september and giving it more fertilization by then.

Needle size is ok, and i've been able to select the buds produced this summer.

Now i need to find time to wire the pine to let light and air in the tree and develop the backbudding

I will decandle a bit earlier next year. Advice always welcome.