Fall pruning: before or after leaves have fallen?

[ajm55555]

I'd like to know your opinion on whether you would prune a JM or a deciduous tree in general before or after the leaves have fallen.
A reason to prune before, let's say a month before the temperature drops: you give the tree some time to heal the cuts.
A reason to prune after: all the sugars in the leaves have flown back into the roots, i.e. it's not lost from the pruning.

 

[Shibui]

A reason to prune before, let's say a month before the temperature drops: you give the tree some time to heal the cuts.

is a valid reason but also factor in that pruning just before leaf fall can cause new shoots to grow that won't be hardened off when leaves should fall. Depending on location that may be no problem or bigger problem. One year I pruned late and the new shoots did not drop leaves that winter (mild climate) so the Japanese maples were evergreen for a year. Fortunately reverted to normal growth cycle next summer and winter.
Compartmentalization is now recognised as a way that plants can seal off wounds well before the actual healing process starts. Some infection is possible but, in the main, plants can defend wounds from most diseases.

A reason to prune after: all the sugars in the leaves have flown back into the roots, i.e. it's not lost from the pruning.

Trees seem to have plenty of reserves to cope with temporary losses. We would not be able to defoliate or prune any time if losses were significant and most species would have died out long ago from storm damage or browsing by animals.

Another reason for pruning after leaves drop is that we can see what is happening, where shoots start and finish, etc.

I now do a post leaf fall structural prune on all deciduous here. No problems noted.

 

[Paradox]

After imo. Best time in January or February just before it starts to wake up from dormancy

Pruning too early could cause the tree to push new growth which you don't want using energy to do just before winter

 

[Shibui]

After imo. Best time in January or February just before it starts to wake up from dormancy

Pruning too early could cause the tree to push new growth which you don't want using energy to do just before winter

Interesting. Pruning JM just before waking up from winter sees copious 'bleeding' here so many of our growers now avoid late winter pruning on JM unless root pruning at the same time.
After many years of pruning straight after leaf drop through to mid - winter I have never seen or heard of a deciduous tree pushing new growth early as a result of pruning.
Possible climate related differences in response?

 

[Paradox]

Interesting. Pruning JM just before waking up from winter sees copious 'bleeding' here so many of our growers now avoid late winter pruning on JM unless root pruning at the same time.
After many years of pruning straight after leaf drop through to mid - winter I have never seen or heard of a deciduous tree pushing new growth early as a result of pruning.
Possible climate related differences in response?

I think you misread my statement.

If you prune mid to late winter when it's dormant it won't push new growth. Pruning before leaf drop (September here) might cause new growth as the tree will try to replace those leaves while there is still active growth. After leaf drop is fine but it will be a long time for the cut to start to heal which some like to avoid. I've pruned after leaf drop when I needed to in order to get the tree to fit in the coldframe.

January here is mid winter. February is a month before buds swell so should not cause bleeding. I probably should not have put the word "just" in my statement. January is probably the best time if bleeding is a problem.

 

[Maiden69]

According to the last Fall pruning stream at Mirai, he stated that the best time is right after the leaves turn color. Which means that the tree moved the "sugars and starches" back into the vascular tissue. This way the tree sets buds for next year. I think the logic was that if you prune before the tree wakening, you will remove the buds that the tree already set to expand, inciting the tree to push whatever buds are left with excessive energy giving you coarse growth. Just like the difference between chopping on bud break vs chopping post harden.

 

[ajm55555]

This way the tree sets buds for next year. I think the logic was that if you prune before the tree wakening, you will remove the buds that the tree already set to expand, inciting the tree to push whatever buds are left with excessive energy giving you coarse growth.

I completely agree with this statement. Usually the apical buds get most of the energy and thus are bigger than the secondary ones. If you cut in early Spring, the tree will send a lot of energy to buds that were not meant to receive it. Not a life or death issue but still, if you do that in the Fall the tree has time to react.

 

[GGB]

In Andreas maple book he says the best time is right as the leaves are changing color. The maple should heal rapidly. And apparently mirai guy says so too @Maiden69

 

[GGB]

Like shibui said I definitely wouldn’t do it a month before they change or the tree could grow but once nights start hitting freezing, the pruning won’t cause growth. At least in my climate

 

[ajm55555]

If you prune mid to late winter when it's dormant it won't push new growth. Pruning before leaf drop (September here) might cause new growth as the tree will try to replace those leaves while there is still active growth. After leaf drop is fine but it will be a long time for the cut to start to heal which some like to avoid.

I agree that new growth too late might be a problem, especially concerning the development of the buds for the next season.
I guess in my case, the best way to go is prune after the leaves have fallen and protecting the wounds from infections.

 

[Paradox]

I'm trying not to say months because season changes happen at different times depending where in the world you are.

Fall color change indicates the sap fallling in the tree in preparation for winter so there should be no further growth after that for sure. If you want to enjoy the fall color of your trees, I see no problem with waiting another few weeks to prune. Being able to see the branches without leaves helps to see the structure better and make choices. I know you can just cut off the leaves as well but I like to enjoy the fall show so I'll wait to do that.

I think any time after leaves are pretty much done changing colors to falling off until mid winter is fine. I've been told cutting too early with so much time before the tree can heal can be a problem but maybe that has been bebunked?

Most deciduous trees will pop new buds at old nodes fairly reliably even with late pruning. I agree sap bleed could be an issue and should be avoided if it is.

 

[Kanorin]

Andrew Robson and Ryan Neal both advise a great time for pruning deciduous (especially maples) is in the fall within about 10-14 days of the leaves changing color. They specifically state that this timing is better than pruning in the middle of the winter - though I'm not aware of any hard evidence to back this.

The theory at least is that the chlorophyll is being re-adsorbed at that time and redistributed to the buds. And because as the colors are changing, the tree is moving around chlorophyll, sugars and starches it can still compartmentalize small wounds quite well. Only prune twigs that you can cut with scissors, though. A large wound (like you would make with concave or knob cutters) will not have time to compartmentalize or heal.

 

[NaoTK]

Only prune twigs that you can cut with scissors, though. A large wound (like you would make with concave or knob cutters) will not have time to compartmentalize or heal.

This is a key point.

At least in the PNW trees here are still actively generating backbuds during winter following a fall prune. I'm talking December January I see new back buds activate getting set up for spring. If you do your prunes in Spring you lose a lot of time while the tree plays catch up

 

[badatusernames]

When trees are shown in full autumn colors, have they simply been pruned at the “wrong” time for the sake of a show? Dumb question but I’ve been trying to figure out an exact answer, as I have maples that have extended growth that I’d love to see in shape for the autumn explosion.

 

[Paradox]

This is a key point.

At least in the PNW trees here are still actively generating backbuds during winter following a fall prune. I'm talking December January I see new back buds activate getting set up for spring. If you do your prunes in Spring you lose a lot of time while the tree plays catch up

I agree, we need to distinguish between pruning then ends of the branches vs cutting off the branches themselves which I guess is what I am thinking of when being concerned with healing the wounds.

Pruning twigs can pretty much happen any time and it is done throughout the summer to prune back extension growth to keep the tree compact.

We have seen Mach5 prune his maples and beech in January and February to select which buds and branch tips he wants to keep

 

[Maiden69]

We have seen Mach5 prune his maples and beech in January and February to select which buds and branch tips he wants to keep

@MACH5 had a conversation with Ryan, and Ryan brings this up on almost every stream that has a question about fall cutback. In the case of Sergio, in his location he experience negative reactions from the trees, dieback, etc... when pruning at leave fall. This is why he does it in spring. So I guess it is not "all inclusive" and dependent on the location that you are. Must be an NY/NJ wood nymph messing up with Sergio's trees.

 

[Damage Inc]

I agree, we need to distinguish between pruning then ends of the branches vs cutting off the branches themselves which I guess is what I am thinking of when being concerned with healing the wounds.

Not to hijack this pruning thread but when is the "best" time to remove larger branches on JMs?

 

[NaoTK]

Not to hijack this pruning thread but when is the "best" time to remove larger branches on JMs?

June, or just after the leaves harden off in spring

 

[pandacular]

June, or just after the leaves harden off in spring

I'm curious about this, as it would seem to waste a good deal of energy that the tree put into those branches. Is this timing to prevent dieback? I plan on making significant cut backs to the leggy bits of each of the main branches, likely in the time around leaf drop, so I'm curious if that would affect my timing.

 

[NaoTK]

Some benefits of a June prune are 1. the tree is at peak growth rate so you get maximum backbudding from a hard prune. and 2. The wound immediately starts healing over. I have seen large cuts mostly heal by the winter.

If I think about a SPRING hard chop.... the tree is still spreading resources out and may not react optimally to a local hard chop. But I have never done a spring hard chop...