J. Maple Pruning Best Practices

[elijah_moncrieff]

I have several maples that are getting to the refinement phase and in this process I am
running into all sorts of pruning nubs, stubs, good and bad pruning scars etc. from when I was "maintenance pruning" my trees.
More or less, I wasn't taking the hobby as serious as I am now, and want to do things right going forward.
What I am wondering is what are some of the best practices when it comes to pruning maples?
To be more specific:

When pruning first year growth how close do you prune to where you want the final cut to be?

If pruning a smaller branch do you leave a stub and wait (1, 2, 3 years) for the branch to get larger to remove the stub
in hopes that it would heal better since the branch would be stronger?

If pruning on woody/medium sized branches do you prune back to the location you want the scar to begin forming,
or practice the same as above and wait to cut back to where the tree dies back to naturally?

Do you have different habits based on the time of year you are pruning, and if so what are they?

To add context, this is what I do currently:

Small and first year branches, I leave a stub (1/4" or less) to naturally die back and return later to clean it up.
Medium and large woody branches I cut where I want the scar to form and cut into live wood to minimize the number of times I have to prune,
using cut paste/putty to aid in healing.

 

[Gabler]

I also leave a stub for large cuts and clean it up later, unless I'm very confident I will see no dieback.

 

[Shibui]

Are we talking Japanese maples, trident maples or other Acer species? JM have slightly different requirements from tridents. Apologies, just checked the thread title - JM.
JM are definitely more finicky than most other maples.

• I leave a short stub on smaller twigs, just to make sure I don't damage the dormant buds in the leaf axils. The stub will die back in a few weeks. Clean up anytime but I usually wait until the new shoots are growing strong to avoid damage.
• Medium cuts at a branch junction can be cut right at desired cut line provided there's a strong branch to maintain sap flow.
• Large cuts and chops into much older wood can have unintended die back right down to roots so I tend to do such cuts slowly over a period. Reduce branch/trunk to be removed to minimum live shoots to reduce sap flow but maintain some flow for a few months or a year. This allows the tree to reroute sap flow from roots to the remaining branches. Final reduction can then happen more safely.

One of the big problems with refining JM is long internodes they tend to grow every Spring. We can't get good ramification with long internodes so I'll often have to remove all spring shoots entirely. Summer flush of growth is usually much more useful to build the ramification we need.
The other problem we see is multiple shoots after pruning. JM can produce 3-10 buds at any node. If those shoots are allowed to develop that area quickly swells to unsightly inverse taper. I spend a lot of time through Summer hunting for areas of multi shoots hiding under the foliage. Religiously remove excess buds and shoots as soon as possible to avert inverse taper.

 

[MACH5]

I will add that specially in refinement, Japanese maples specifically will thicken quickly. So it is important to pinch early! Otherwise you will see a thickening of the twigs that will basically ruin the fine ramification that we strive for. I see this happening often because people of course have lives (unlike me!) and don't get to them as quickly as they should. In very strong areas I even take out one leaf out of each pair as they come out in spring to restrict that shoot from its ability to fully photosynthesize and thus thicken.

 

[Cadillactaste]

I will add that specially in refinement, Japanese maples specifically will thicken quickly. So it is important to pinch early! Otherwise you will see a thickening of the twigs that will basically ruin the fine ramification that we strive for. I see this happening often because people of course have lives (unlike me!) and don't get to them as quickly as they should. In very strong areas I even take out one leaf out of each pair as they come out in spring to restrict that shoot from its ability to fully photosynthesize and thus thicken.

Proper head tilt. As I do when I go into deep thought. Taking one leaf of the pair. Fascinating...thanks for sharing.

 

[elijah_moncrieff]

Are we talking Japanese maples, trident maples or other Acer species? JM have slightly different requirements from tridents. Apologies, just checked the thread title - JM.
JM are definitely more finicky than most other maples.

• I leave a short stub on smaller twigs, just to make sure I don't damage the dormant buds in the leaf axils. The stub will die back in a few weeks. Clean up anytime but I usually wait until the new shoots are growing strong to avoid damage.
• Medium cuts at a branch junction can be cut right at desired cut line provided there's a strong branch to maintain sap flow.
• Large cuts and chops into much older wood can have unintended die back right down to roots so I tend to do such cuts slowly over a period. Reduce branch/trunk to be removed to minimum live shoots to reduce sap flow but maintain some flow for a few months or a year. This allows the tree to reroute sap flow from roots to the remaining branches. Final reduction can then happen more safely.

One of the big problems with refining JM is long internodes they tend to grow every Spring. We can't get good ramification with long internodes so I'll often have to remove all spring shoots entirely. Summer flush of growth is usually much more useful to build the ramification we need.
The other problem we see is multiple shoots after pruning. JM can produce 3-10 buds at any node. If those shoots are allowed to develop that area quickly swells to unsightly inverse taper. I spend a lot of time through Summer hunting for areas of multi shoots hiding under the foliage. Religiously remove excess buds and shoots as soon as possible to avert inverse taper.

This is great information, thank you for the clarification and for giving the purpose for why you do those things. Sounds like I’m not too far off with my current practices but will keep what you explained in mind when it comes to larger cuts to prevent unwanted dieback.
I am curious what you do differently for tridents however? I do have tridents in my collection, just not as far along as my mountain & j. maples.

 

[elijah_moncrieff]

I will add that specially in refinement, Japanese maples specifically will thicken quickly. So it is important to pinch early! Otherwise you will see a thickening of the twigs that will basically ruin the fine ramification that we strive for. I see this happening often because people of course have lives (unlike me!) and don't get to them as quickly as they should. In very strong areas I even take out one leaf out of each pair as they come out in spring to restrict that shoot from its ability to fully photosynthesize and thus thicken.

When you say pinch early, do you allow some elongation of the new buds that are emerging, or are you pretty quick to get them before they get any substantial length?

 

[Cadillactaste]

When you say pinch early, do you allow some elongation of the new buds that are emerging, or are you pretty quick to get them before they get any substantial length?

This explains it well. With photos.

Pinching spring buds on Japanese maple - Bonsai Tonight

How-to article about pinching springs buds on Japanese maple bonsai to maintain compact growth and short internodes for trees in refinement.

bonsaitonight.com

 

[MACH5]

When you say pinch early, do you allow some elongation of the new buds that are emerging, or are you pretty quick to get them before they get any substantial length?

Ideally very early as the first leaves begin to unfold and not after they have extended.

 

[AGentleman]

I am curious what you do differently for tridents however?

I am also curious.

 

[Shibui]

Tridents do not have the same penchant for over thickening so it's not quite as critical to remove excess buds really early.
Tridents shoot new buds more reliably for me so I can let them grow, knowing I can chop back at some stage and get a good response.
In refinement and maintenance stage we don't have to pinch tiny shoots as soon as the first leaves start to emerge. Allow spring shoots to grow to 2-4 pairs of leaves then cut back tridents.
Do keep watch for stray shoots that come from lower branches and grow up through the canopy. No problem in immature trees but hard to spot in well developed trees with dense branching. These shoots can overthicken a lower branch is left unchecked and will also leave unwanted pruning scars when you finally notice them after leaves drop.
Pruning larger branches and trunk chops pretty similar for both species.