Pruning For Shortening Internodes and Compaction.

[mrcasey]

I still don't quite understand the procedure and timing for shortening branch internodes on shimpaku. The photo is a branch on a shohin Itoigawa. It's already gotten a bit leggy. I'd like the next node to be roughly where the red line is. Do I just cut the branch off there? What time of year should I do it? I feel like I've tried this before and it just weakened or killed the branch...

 

[Wires_Guy_wires]

In general, we cut back running shoots.
And these shoots don't run: there is no extending shoot.
So pruning these back, will cause them to weaken and die. Your primary aim for branches like this is building up strength by good sun exposure and dosing nutrients and water accordingly. The branch will then send out extending shoots; shoots that have one tip grow a couple inches in the growing season. Later we cut those shoots back, to build up everything behind it.

But if the energy isn't there, pruning it would only lower the photosynthetic surface and thus signal the plant that this branch is not worth keeping.

Now if ALL the branches look like this, there is a balance. And the plant will stay weakish for about 6 years before going belly up.

Juniper growth in my mind, is a wave/curve system.. You build and build and build, then on the top of the curve you cut them back, setting the curve back to a dip. Then you repeat.
If you skip the building, you just lower the bottom of the curve, meaning it will go weaker and weaker.

Some of my junipers have taken 4 years for branches to start running. But they backbud like crazy when they do. And you can in fact cut the running ones to divert energy to the weaker ones.

I hope this helps! Maybe someone who is more experienced than I am has some corrections or improvements on my response.

 

[AshleyMammal]

Great question! Great answer!

 

[crab apple]

In general, we cut back running shoots.
And these shoots don't run: there is no extending shoot.
So pruning these back, will cause them to weaken and die. Your primary aim for branches like this is building up strength by good sun exposure and dosing nutrients and water accordingly. The branch will then send out extending shoots; shoots that have one tip grow a couple inches in the growing season. Later we cut those shoots back, to build up everything behind it.

But if the energy isn't there, pruning it would only lower the photosynthetic surface and thus signal the plant that this branch is not worth keeping.

Now if ALL the branches look like this, there is a balance. And the plant will stay weakish for about 6 years before going belly up.

Juniper growth in my mind, is a wave/curve system.. You build and build and build, then on the top of the curve you cut them back, setting the curve back to a dip. Then you repeat.
If you skip the building, you just lower the bottom of the curve, meaning it will go weaker and weaker.

Some of my junipers have taken 4 years for branches to start running. But they backbud like crazy when they do. And you can in fact cut the running ones to divert energy to the weaker ones.

I hope this helps! Maybe someone who is more experienced than I am has some corrections or improvements on my response.

Oh boy, just when ya think ya got it figured out more info comes along. I hope I haven't killed my junipers. Now I see what those shoots are all about.
What if you have a somewhat styled juniper and those running shoots are looking crazy, do you have to just let them go for a season?

 

[Wood]

Here's a good summary from @Brian Van Fleet with photos that might help visualize what @Wires_Guy_wires is saying

Itoigawa Trimming

This tree was tidied up for the Alabama club show in May, and left to grow until mid-August, when I trimmed it up again in preparation for the fall growth spurt. Look at those strong runners. Left …

nebaribonsai.wordpress.com

 

[bwaynef]

The photo doesn't do any favors, but it shows enough to know that tree's not strong enough to work. Mirai has popularized that "the strength in junipers is in the foliage," but I think its better said that the strength in junipers is in the tips. Pinching (removing foliage tips) junipers is fairly universally known to weaken them. Allowing one or two tips to extend really seems to send the whole system into over-drive. Also, removing weak growth (hanging down or too far inside) seems to be a net positive for the system.

Other than that, ...what WGW said.

Its hard to say without seeing the whole tree, but I'd put this one in the sun, make sure its watered regularly and in good soil, and leave it alone until the character of the growth changes to where its obvious you need to do something with it. You'll get "there" a lot faster by not messing with it right now.

 

[Paradox]

I still don't quite understand the procedure and timing for shortening branch internodes on shimpaku. The photo is a branch on a shohin Itoigawa. It's already gotten a bit leggy. I'd like the next node to be roughly where the red line is. Do I just cut the branch off there? What time of year should I do it? I feel like I've tried this before and it just weakened or killed the branch...

View attachment 572830

I agree with the others above. If the whole tree looks like this, its too weak to do any cut backs right now.
Cutting back now will probably end up killing those branches.
My advice is the same: to leave it be for the winter and next spring start feeding this tree every 2 weeks to every month and see how it responds to that.
If and when it starts getting strong and vigorous growth, then you can cut it back to try and induce back budding.

 

[mrcasey]

Thanks wgw for the very precise advice. I think I understand the way forward a bit better now. Here's a pic of the entire plant. It was grown from a cutting that I got from Brent Walston.

 

[Wires_Guy_wires]

What if you have a somewhat styled juniper and those running shoots are looking crazy, do you have to just let them go for a season?

It depends on your goal, but generally speaking you let them go for a season, then cut them back. They will be strong enough sometimes, that you'd have to repeat the whole process 4 times a year in some cases.
Most of the times, it's two cutbacks a year, in a healthy plant.

Trees that went into shows, usually take two years to recover because people don't let them do that initial run. I've heard it, but never experienced it myself.. But after a while, once the plant is nice and dense, the runners will spread out more evenly and take less hard cut backs to stay in shape. The total amount of growth will be the same, but due to the balance between all the foliage, all those inches of growth are now spread out over multiple branchlets. If you'd add those up, they'd still add up to a couple inches, but since they're spread evenly over all the branchlets, the plant tends to keep its shape.

In the picture just posted, we see one of those running shoots next to the black wire on top, and one on the right hand side.
These are starting to run, but they haven't really gained any momentum.
My advice would be to wire the structure to let in light, but cut nothing until you see those runners on 30-40% of the shoots.