How fast do juniper trunks thicken?

[justBonsai]

Hi,

I purchased a small kishu juniper from Chikugo-en at Bonsai-a-thon. I intend finish the tree in the shohin size range. Although slightly late, I felt the tree was in good enough health to do a minor repotting. I used a saw to trim a thin layer of the outer roots and roughed it up slightly to expose tips. The tree is now repotted in a slightly larger container which it will remain until I slip it into a colander next year or so.

The branch placement and shape of the tree is pretty much there already so I will just need to work on ramification and growth. From letting the tree grow largely unrestricted for 2-3 years how much more growth can I expect? I don't expect 1 inch+ , but I'm hoping at least 1/4 - 1/2 inch to give it a slightly more "robust" look.

Thanks,
Julian

 

[Dav4]

In a pot, junipers thicken at a snail's pace. If you really want to thicken the trunk without planting in the ground, using a colander or pond basket might be the best way to go.

 

[Brian Van Fleet]

If you're trying to thicken the trunk, you don't want to also do root work and develop ramification.
You'd want to get it out of the pot and into the ground. In the ground, once it gets going, you could get 1/4" of diameter a year in year 2, and probably another 1/4" in year 3. After that, it can accelerate a bit, but it will have developed some sacrifice branches which will give you some bulges to deal with.

 

[just.wing.it]

I bought a tiny juniper last summer, a stick in a pot really. Gonna plant it the ground for, who knows how long. I plan on keeping a record of the trunk growth. I also have one that is similar in size that I will keep in a pot, to compare the two.
Colander, grow box, grow bag, all good options.

 

[Atrox]

Leave instructions in your will to continue the measurements hahahahaha

 

[just.wing.it]

Leave instructions in your will to continue the measurements hahahahaha

Already did that

 

[justBonsai]

If you're trying to thicken the trunk, you don't want to also do root work and develop ramification.
You'd want to get it out of the pot and into the ground. In the ground, once it gets going, you could get 1/4" of diameter a year in year 2, and probably another 1/4" in year 3. After that, it can accelerate a bit, but it will have developed some sacrifice branches which will give you some bulges to deal with.

I'll just slip it in the ground next year. Since I don't really want to disturb the roots more. Would colander growing give me any respectable growth or is it ground only?

 

[Adair M]

Ground is the best way to get trunk girth.

Colander growing gives you root ramification, especially closer to the trunk.

Junipers are less likely to create the long "tap" roots that pines and maples do. Therefore, colander growing is not used as much with junipers. Junipers tend to make a fibrous root system naturally. Therefore, if trunk girth is your objective, grow in the ground.

 

[Anthony]

Unless a tree will naturally thicken in a pot, ground growing is better.

You would need a cutting or second plant of the same type to test with an extension branch at 3 to 6 to 10 feet.
Expect to blow out a year or two or three doing tests.

You must first however achieve - Health -, you need to learn to make the plant sit up and beg --- so to speak.
Good Day
Anthony

*Posting at the same time as you Sifu.

 

[chicago1980]

Sifu interesting to hear this term in Bonsai.

 

[Brian Van Fleet]

I'll just slip it in the ground next year. Since I don't really want to disturb the roots more. Would colander growing give me any respectable growth or is it ground only?

Not really. What gives you better growth is to let the foliage develop a head of steam. This is accomplished by not pruning or trimming foliage, or working on the roots. Planting in a bigger pot (or the ground) only means that the foliage can support a larger root system, which in turn, can support more foliage. More growth = more wood.

For a little perspective on what you can expect in 5, 15 or 30 years:
Here are a pair of Kishus, pencil-thick cuttings in 4" pots in '10, and after 5 years in the ground; around 1" trunk:


This Itoigawa was grown 15 years in a 1-gal can. Lots of food, and not a lot of pruning resulted in a 1.5"+ trunk.

This shimpaku was container grown in a wooden box for 30 yards and has a 4"+ trunk. It was also 4' tall and 4' wide.

 

[chicago1980]

Not really. What gives you better growth is to let the foliage develop a head of steam. This is accomplished by not pruning or trimming foliage, or working on the roots. Planting in a bigger pot (or the ground) only means that the foliage can support a larger root system, which in turn, can support more foliage. More growth = more wood.

For a little perspective on what you can expect in 5, 15 or 30 years:
Here are a pair of Kishus, pencil-thick cuttings in 4" pots in '10, and after 5 years in the ground; around 1" trunk:
View attachment 96093 View attachment 96094 View attachment 96095

This Itoigawa was grown 15 years in a 1-gal can. Lots of food, and not a lot of pruning resulted in a 1.5"+ trunk.
View attachment 96091
This shimpaku was container grown in a wooden box for 30 yards and has a 4"+ trunk. It was also 4' tall and 4' wide.
View attachment 96089

Wow!

 

[drew33998]

I have a dozen or so shimpaku cuttings from three years ago. They are all in pots growing unchecked and only have put on 1/4" caliper in three years. Last year they did most of the bulking up. Hoping year four is even better

 

[justBonsai]

I can't get any pictures right now but the form of the tree is pretty much there already. I don't need to bulk the trunk significantly, but my goal is to add at least 1/4 inch more. After that I'll spend 2-3 years or so to rebuild the ramification and branching and stick it in a small pot to enjoy.

I'll slip pot it in a colander later this season if the roots grow well and try to let it put on as much unrestricted growth as possible.

 

[Smoke]

Unless a tree will naturally thicken in a pot, ground growing is better.

And that my friends....just about covers it.