Structural Pruning of Japanese Maples

[AlainK]

In which occasion (if any) could a JM be safely chopped during the active growing season to a point where there are not any lower shoots/branches on the trunk?

It depends : if you can see horizontal "lines" on the trunk and chop above, it will backbud, especially when donr early in the season and providing the cut is sealed.

It can be done : show us a photo with details if you want a more accurate answer, but yes, it's definitely a possibility. Sorry Derek7745, but I have to contradict you : it is possible

EDIT : oh, you wrote "safely" ?

Then you're (partly) right, anything done, meddling with a living thing is never safe. But that's "making a decision", you must know, "feel" your trees, and then, take a deep breath and plunge...

 

[Deleted member 21616]

Sorry Derek7745, but I have to contradict you : it is possible

no apologies necessary - i think we completely agree

it is of course possible. it has been done many times. and as you explain, there are way to increase likelihood of success. but can it ever be done 'safely'? i guess it depends on what you mean by safely.

i have read more than once on this forum that member's trees have died back right to the roots even when all precautions were taken. curious what you think about that? You much have more experience than i do!

 

[BobbyLane]

I would like to ask a question but at the same time to say a Big Thanks for all the valuable information contained here in this thread.
My question is : In which occasion (if any) could a JM be safely chopped during the active growing season to a point where there are not any lower shoots/branches on the trunk?
Thank you in advance.

these types of things you should just try for yourself, maples dont need to be wrapped in cotton wool.they can be worked on and different methods tried like any other decidous tree...
in the last few weeks ive done exactly this, cut back to no branches or twigs.
instead ive cut back to shoulders on the trunk or branch and left some reserve, ive done this in three different maples, katsura, kito hime and sango kaku....the sango kaku was cut back to a shoulder that had a visible node, that nod is red and swelling up now. im quite confident the other two will do the same, we have not had much sun in london though so its taking longer?

 

[BobbyLane]

this acer phoenix was chopped back at the start of feb, before active growth, but it was kept in a greenhouse

feb 1st
20190201_172729 by Bobby Lane, on Flickr

feb 27th

although this one had been chopped to a visible branch
20190227_152425 by Bobby Lane, on Flickr

today

i had to rub out loads of buds already, i only need a fork of two emerging at this tip
2019-04-12_05-54-19 by Bobby Lane, on Flickr

what did i learn? i know now, that on a healthy maple i can chop back to a shoulder and the tree should bud back from there with or without any visible branches. its not a beech

ive also learned that i can chop back a maple, before active growth and it will back bud like crazy when growth begins like any other deciduous tree. but i just have to leave some reserve above a strong shoulder, to reduce the chance of die back occurring.

 

[Deleted member 21616]

a point where there are not any lower shoots/branches on the trunk?

@BobbyLane i guess it depends how low you cut on the trunk? yours are pretty high so your chances are higher with regards to stored energy and budding opportunities! ever try cutting as low as Peter Adams says you can do on page 35? (he roots prunes at the same time...)

 

[0soyoung]

Energy, carbohydrates, are stored as starch grains in the vacuoles of living cells throughout the tree. IOW, when one prunes, they remove only the portion of the stored energy that 'belongs' to the portion removed. The remaining tree has the same amount of stored energy as it had before.

An issue as I see it, is what are the odds that a bud is released on the most distal node? I don't have data, just a prejudice based on what I think I remember of my experiences. I think it close to 100% if the bud is visible before pruning. I think it is less otherwise. I think these odds are highest around the time 'buds swell' (cytokinin levels are presumably high).

 

[Deleted member 21616]

Energy, carbohydrates, are stored as starch grains in the vacuoles of living cells throughout the tree. IOW, when one prunes, they remove only the portion of the stored energy that 'belongs' to the portion removed. The remaining tree has the same amount of stored energy as it had before.

in order words, more remaining trunk/branch matter = more energy (not in term of ratio or percentage, but in terms of there just being more of it in all that makes up the physical tree), and more energy (in that sense) and more buds = more chance at budding?

i can take 2 feet off a 10 foot branch, or 8 feet off a 10 foot branch. the former sounds safer?

 

[BobbyLane]

@BobbyLane i guess it depends how low you cut on the trunk? yours are pretty high so your chances are higher with regards to stored energy and budding opportunities! ever try cutting as low as Peter Adams says you can do on page 35? (he roots prunes at the same time...)

remember this one?

a couple days ago this is what happened
i will update that thread later in season
its planted on a tile in the grow bed.eventually it will be a broom that breaks into three sub trunks, but with far better proportions. will just leave it to extend and fatten up, feed with chicken pellets.
i have so many projects on the go i can apply varied methods and document results

 

[0soyoung]

i can take 2 feet off a 10 foot branch, or 8 feet off a 10 foot branch. the former sounds safer?

As far as energy is concerned, it does not.

Consider a pile of 10 living cells, each with a starch grain in their individual vacuoles. If I remove 2 cells, the remaining 8 still have the exact same energy as before. If I remove 8 cells, the remaining 2 still have the exact same energy as before.

Maybe it is 'safer' to remove only 2 feet off a 10 foot branch, but it is likely to be due to some other reason.

 

[Deleted member 21616]

As far as energy is concerned, it does not.

Consider a pile of 10 living cells, each with a starch grain in their individual vacuoles. If I remove 2 cells, the remaining 8 still have the exact same energy as before. If I remove 8 cells, the remaining 2 still have the exact same energy as before.

Maybe it is 'safer' to remove only 2 feet off a 10 foot branch, but it is likely to be due to some other reason.

in order words, more remaining trunk/branch matter = more energy (not in term of ratio or percentage, but in terms of there just being more of it in all that makes up the physical tree

the tree as a living unit has a greater total volume of energy. So let's say back budding is a 1/5 chance. I rather have a tree with a total remainder of 50 'energy units' rather than a total of 3 'energy units'.

using my imagination here - maybe this makes no sense at all LOL

what i experience this year is pruning a 24" inch branch down to 4" will give me 2-3 back buds. pruning a 24" branch down to 12" inch will give me 6-10 back buds

 

[0soyoung]

the tree as a living unit has a greater total volume of energy. So let's say back budding is a 1/5 chance. I rather have a tree with a total remainder of 50 'energy units' rather than a total of 3 'energy units'.

using my imagination here - maybe this makes no sense at all LOL

what i experience this year is pruning a 24" inch branch down to 4" will give me 2-3 back buds. pruning a 24" branch down to 12" inch will give me 6-10 back buds

Back budding is simply the release of latent buds. It is caused by cytokinin in excess of auxin locally (there may be a threashold value for 'excess' that is different from unity). There is, of course, some expenditure of energy in each bud.
It isn't until the leaves are 'hardened' that they contribute energy (carbohydrates) to the tree; prior they are energy (carbohydrate) consumers.

 

[Gaston]

Good post

 

[KiwiPlantGuy]

Hi,
Unsure if this helps as I am in Zone 9.

As you can see I chopped this down to less than 6 inches to start my trunk again. And you can see all the little new buds popping.
Seems like this thread has a whole load of over thinking via theory and not much practical experience.
So my comment is simply, try it on something you don't mind losing, and then get more courageous ?
Charles

 

[AlainK]

i have read more than once on this forum that member's trees have died back right to the roots even when all precautions were taken.

I think that, frankly, it's hard to kill an Acer palmatum that has been well cultivated.

"more than once", people lose trees because of lack of experience, because they don't know the tree, because they are not "in connection" with the tree. See what I mean ?

 

[leatherback]

If your palmatum is healthy and strong, anytime up to summer equinox should give you reliable back-budding if you cut back hard. After the longest day, your plant may be tempted to not push foliage until spring.

Naturally, if you cut down to the roots this is a different story.

Personally I would do it in winter well before bud-break, of after the first flush has run its course and the new foliage have started to mature.

 

[0soyoung]

Seems like this thread has a whole load of over thinking via theory and not much practical experience.

Yah, it always happens when the question includes the words, 'the BEST time'. Some of us have enough experience to have seen a lot of ways it can go wrong. Some of us like to understand why stuff happens. Some of us just like to be contentious, if not always, sometimes. And then there is always the discovery of, best, in what way?

BUT, you are absolutely right

simply, try it

and see what happens.

The noob experience is indeed terrifying, but it is the way expertise is created.

 

[Deleted member 21616]

Some of us like to understand why stuff happens. Some of us just like to be contentious, if not always, sometimes. And then there is always the discovery of, best, in what way?

100%

i feel like i’ve read and even participated in discussions about chopping before

but every discussion yields new insights, new ideas to test out, new things to pay attention to, and so on

 

[Cajunrider]

If your palmatum is healthy and strong, anytime up to summer equinox should give you reliable back-budding if you cut back hard. After the longest day, your plant may be tempted to not push foliage until spring.

Naturally, if you cut down to the roots this is a different story.

Personally I would do it in winter well before bud-break, of after the first flush has run its course and the new foliage have started to mature.

You must have meant summer solstice. Is that correct?

 

[leatherback]

You must have meant summer solstice. Is that correct?

Yes. I should really not try to use fancy words
I meant, if you chop after the longest day, you run the risk of the plant not pushing foliage and just going dormant till spring. (I have unfortunately seen this in Tillia: Defoliating after mid june has left me with bare trees till april the year after, and die-back). I do not know how sensitive AP is, but .. better safe than sorry, if you have the choice.

 

[Cajunrider]

Yes. I should really not try to use fancy words
I meant, if you chop after the longest day, you run the risk of the plant not pushing foliage and just going dormant till spring. (I have unfortunately seen this in Tillia: Defoliating after mid june has left me with bare trees till april the year after, and die-back). I do not know how sensitive AP is, but .. better safe than sorry, if you have the choice.

Please know that I didn't mean to point out the wording thing. With English being my second, well actually third language, heaven knows I've made my fair share of errors. I just wanted to make sure I understand your advice correctly.