Improve juniper scion grafting success: cut off the apical tip?

[Wires_Guy_wires]

For a couple years I've been grafting scions onto junipers.
Some take better than others, and it seems to be somewhat of a crapshoot whether they take or not.
From close to 60 observations I've noticed that my scions have a higher success rate when the apical tip was removed, with blaauw being the exception.

Anyone else noticing something similar?
I think I can apply a logic here that auxin seems to suppress the callus formation - or the growing tips draw much more water than the wound can provide - and that a higher cytokinin level (by removal of the tip) seems to improve the success rate.
It's probably both.

But I'd like to hear your input. Let's discuss this!

 

[rifujiin]

For a couple years I've been grafting scions onto junipers.
Some take better than others, and it seems to be somewhat of a crapshoot whether they take or not.
From close to 60 observations I've noticed that my scions have a higher success rate when the apical tip was removed, with blaauw being the exception.

Anyone else noticing something similar?
I think I can apply a logic here that auxin seems to suppress the callus formation - or the growing tips draw much more water than the wound can provide - and that a higher cytokinin level (by removal of the tip) seems to improve the success rate.
It's probably both.

But I'd like to hear your input. Let's discuss this!

Even though I don't know the answer to this. I would like to ask something since you look like someone with experience in grafting. Let's say I totally change the foliage of a tree successfully (mainly talking about juniper and pine) and strip all the old foliage. Will it grow the new foliage type from it's trunk or will it just grow the the old foliage.

 

[misfit11]

I think there might be some truth to this. I don't always cut my scions back before grafting but often do because of the length of a particular one. You cut them back to a smaller size to reduce transpirational stress. But cutting back the apical growth, in particular, might be a big driver in this. The apical growth is the strongest and, therefore, would be the most likely to transpire the most. I'll have to observe this more closely with my grafting and experiment a bit.

Thanks for the interesting observation.

Cory

 

[Wires_Guy_wires]

Even though I don't know the answer to this. I would like to ask something since you look like someone with experience in grafting. Let's say I totally change the foliage of a tree successfully (mainly talking about juniper and pine) and strip all the old foliage. Will it grow the new foliage type from it's trunk or will it just grow the the old foliage.

The buds originating from the trunk will contain the trunk genetics and thus will be the original foliage.
Everything originating from your scions, will be the scions genetics. So if the scion grows out to become a branch, the buds on the branch will be scion genetics too.

I'm having a hard time thinking of an analogy, but in essence you glued two different organisms together that support each other from their sap stream and physical structure, but they don't "combine" their genetics to form a hybrid. For that we'd need sexual reproduction. When you look at old cherry trees that are usually grafted on very vigorous rootstock, we can see that the lower trunk gets huge and forms an insane bulge at the intersection, this is because it's two plants with two different genetic rythms and two different vigors and growth rates.

Does that make sense? If not, I'll have a look to see if I can find a better way to word it.

 

[Wires_Guy_wires]

I think there might be some truth to this. I don't always cut my scions back before grafting but often do because of the length of a particular one. You cut them back to a smaller size to reduce transpirational stress. But cutting back the apical growth, in particular, might be a big driver in this. The apical growth is the strongest and, therefore, would be the most likely to transpire the most. I'll have to observe this more closely with my grafting and experiment a bit.

Thanks for the interesting observation.

Cory

I saw the tips of my cuttings die quite often, I kept them because I wanted them to enforce root production. But I've noticed they have a higher rooting rate when clipped down to a more bushy profile. It took a couple years to try and connect those dots and translate them to scions, which seem to behave similarly.

 

[misfit11]

I saw the tips of my cuttings die quite often, I kept them because I wanted them to enforce root production. But I've noticed they have a higher rooting rate when clipped down to a more bushy profile. It took a couple years to try and connect those dots and translate them to scions, which seem to behave similarly.

Interesting. I haven't noticed this with cuttings. Junipers strike so easily that I never really gave it much thought. I just take a cutting and shove it in some soil. I don't even think I need rooting hormone. This might be the difference between our climates, IDK. You'd think Netherlands and SF Bay Area would be similar. You might have colder winter temps, though.

All I really take cuttings or scions from is Kishu Shimpaku. I like it's characteristics better than any other Juniper I've had experience with so I figure "why do anything else?". What species/varieties are you taking cuttings and scions from?

 

[Wires_Guy_wires]

What species/varieties are you taking cuttings and scions from?

Mainly itoigawa, and those have a super low strike rate for me. Regular chinensis isn't doing much better. Wild sabina however, the rastrara type, roots by just looking at it. Blaauw is more difficult but I can get those to root reliably by using a girdle for a season. With all other junipers I have no complaints.
Maybe it's because of the birds that pull them from the pots every couple weeks or so.. But in the scions it's a curious thing to see such a difference between the ones with elongated tips and the ones without.