Japanese Maple Development

[SquigLord]

Hey all,

I'm new to this forum and have been practicing bonsai for about 3 years now. I live in the Portland area and I like conifers and deciduous, but I enjoy the latter of the two most.

A couple days ago I extracted a couple of field grown Japanese maples that are in development and I was looking for some guidance on where to go next with them. These trees are about 12 years old now. I dug them up a couple years ago and pruned the roots heavily and replanted them in the field over anderson flats. I cleaned the field soil off this time around and planted them in a 50/50 mix of diatomaceous earth and horticultural grade pumice. I was thinking of letting them grow for the first half of the season and then chopping the trunks pretty well if they are growing vigorously enough in the summer after the leaves have hardened off. Alternatively, I would prune the branches back a bit this winter to promote back-budding in the spring and then chop them in the summer dormancy.

Any thoughts about how I should proceed are very much appreciated, technically or aesthetically.

Thanks!
Spencer

 

[SquigLord]

I forgot to mention that the largest multi-trunk maple had some die-back on the trunk from a root that was pruned hard.

 

[Brian Van Fleet]

The bases have some interesting features, but I suggest you shorten the trunks significantly at the right time to keep your eyes focused on the interesting parts.

 

[Mike Hennigan]

Since you dug them now and not in the spring, do you have a means of protecting them from freezing temperatures for the rest of the winter? Portland is incredibly mild compared to where I live so I would always wait until spring to do this work since I don’t own a temperature controlled greenhouse. But if your temperatures dip consistently into freezing be careful, these should be protected from that until spring. Nice material though!

 

[SquigLord]

The bases have some interesting features, but I suggest you shorten the trunks significantly at the right time to keep your eyes focused on the interesting parts.

Yes, I am planning on chopping the trunks significantly for the first two trees, probably as far down the green trunks as I could get a bud. The multi-trunk tree I was thinking of doing something like a clump style, so I would chop the trunks to about 1/4 the overall height of the tree, depending on the thickness of the trunk.

Since you dug them now and not in the spring, do you have a means of protecting them from freezing temperatures for the rest of the winter? Portland is incredibly mild compared to where I live so I would always wait until spring to do this work since I don’t own a temperature controlled greenhouse. But if your temperatures dip consistently into freezing be careful, these should be protected from that until spring. Nice material though!

I didn't have a good option to wait until closer to spring, unfortunately. The land these trees were planted is being sold soon, so I was kind of forced to dig them up. I don't have a greenhouse... Weather is suppose to stick around 47 where the trees are. Do you think I could just move them into the garage if the temperature going to drop significantly?

 

[Mike Hennigan]

Yes, I am planning on chopping the trunks significantly for the first two trees, probably as far down the green trunks as I could get a bud. The multi-trunk tree I was thinking of doing something like a clump style, so I would chop the trunks to about 1/4 the overall height of the tree, depending on the thickness of the trunk.



I didn't have a good option to wait until closer to spring, unfortunately. The land these trees were planted is being sold soon, so I was kind of forced to dig them up. I don't have a greenhouse... Weather is suppose to stick around 47 where the trees are. Do you think I could just move them into the garage if the temperature going to drop significantly?

I also don’t own a garage ?. Yea I think a garage would be fine, didn’t mean to freak you out with the greenhouse comment.

 

[SquigLord]

I also don’t own a garage ?. Yea I think a garage would be fine, didn’t mean to freak you out with the greenhouse comment.

Haha, yeah I'm a little wary I have been thinking about that myself and I have no real solution, so hopefully the rest of the season is mild and they do alright!

 

[rodeolthr]

Yes, I am planning on chopping the trunks significantly for the first two trees, probably as far down the green trunks as I could get a bud. The multi-trunk tree I was thinking of doing something like a clump style, so I would chop the trunks to about 1/4 the overall height of the tree, depending on the thickness of the trunk.



I didn't have a good option to wait until closer to spring, unfortunately. The land these trees were planted is being sold soon, so I was kind of forced to dig them up. I don't have a greenhouse... Weather is suppose to stick around 47 where the trees are. Do you think I could just move them into the garage if the temperature going to drop significantly?

Fwiw, I routinely dig, chop, and root prune my Japanese maples in my garden in Seattle at this time of year. They often freeze solid in their little training pots, but to date (knock on wood) they have sailed through without damage or issue and push very strong growth in spring. I recently moved about 40 shohin sized trees from growing containers into training pots so that they'll be ready for spring. I do this because I'm not there in spring when new growth starts to emerge and also because of my experience in the nursery industry where trees are routinely dug throughout winter and placed bareroot into storage.

 

[Mike Hennigan]

Fwiw, I routinely dig, chop, and root prune my Japanese maples in my garden in Seattle at this time of year. They often freeze solid in their little training pots, but to date (knock on wood) they have sailed through without damage or issue and push very strong growth in spring. I recently moved about 40 shohin sized trees from growing containers into training pots so that they'll be ready for spring. I do this because I'm not there in spring when new growth starts to emerge and also because of my experience in the nursery industry where trees are routinely dug throughout winter and placed bareroot into storage.

Nice! I figure if you can do that anywhere it would be the Pacific Northwest with the climate you’ve got up there. I don’t think I have the guts to try doing that where I live without any way to keep them above freezing. I guess the other thing I would worry about is opening all these wounds while the tree is dormant for quite some time and won’t be able to compartmentalize disease. Hmm. Thanks for sharing, that’s pretty interesting.

 

[Leo in N E Illinois]

Your plan sounds good.

 

[John P.]

Are the first ones grafted Coral Barks?

 

[SquigLord]

Are the first ones grafted Coral Barks?

They are all green maples I believe. They were actually lions mane maples but some of the stock died and the root stock regrew true.

Fwiw, I routinely dig, chop, and root prune my Japanese maples in my garden in Seattle at this time of year. They often freeze solid in their little training pots, but to date (knock on wood) they have sailed through without damage or issue and push very strong growth in spring. I recently moved about 40 shohin sized trees from growing containers into training pots so that they'll be ready for spring. I do this because I'm not there in spring when new growth starts to emerge and also because of my experience in the nursery industry where trees are routinely dug throughout winter and placed bareroot into storage.

Awesome! Thanks for your experience. I figure that they are pretty hardy, but I left quite a bit of roots on them so they would push strongly this spring as well. I have experienced some die-back from chops before so I try to stay a little more conservative with chops and reduce them gradually over time.

 

[Yoppyx]

What is the optimal chopping season??

 

[SquigLord]

What is the optimal chopping season??

To my understanding, maples bleed a lot during the spring. You can chop them in the winter, summer after the leaves have hardened, or the fall after the leaves have dropped. Arguably the fall chopping is best because it allows the tree to heal somewhat before the winter and push better in the spring. It depends on what else you have done to the tree as well and how vigorous the tree is before the work. For example, you could probably chop a maple planted in the ground any time of the year, however, you might risk some die-back if you do it when the tree is moving a lot of water in the spring.

 

[0soyoung]

What is the optimal chopping season??

How about from 6 weeks before the summer solstice to 6 weeks after.
As a 'season' this roughly corresponds to the 'kids-are-out-of-school' season.