Grafting 101

markyscott

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Cover over the whole thing with cut paste. The main thing you're trying to avoid is water getting inside the graft union. That can interfere with the callousing and increase the chance of failure. So be conscious of this when you're applying the cut paste and ensure a good seal where water may be running down the trunk and can enter the wound.
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By the way, Danny Coffey visited Houston not too long ago and left us with a great tip about cut paste. See this stuff?
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At $14 for the little cup it's darn expensive. See this stuff?
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At $18 for 5 lbs is darn cheap and you can pick it up at Home Depot. Not Loews, weirdly enough (at least the one by my house). According to Danny, the difference is Neem oil. Work it into the duct seal until it's as pliable as you like and then store it in a plastic bag.
 

markyscott

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During the growing season, remove all of the growth on the branch except that growing past the graft union. Do not pinch or prune the growth on the branch - let it extend. How long you leave it in depends on the growth of the tree, but in the case of this trident, it was a full year before I removed it.

As with thread grafting, when you start to see callous over and notice a difference in thickness before and after the graft union, you'll want to wean the scion by slowly weakening the connection along the shoot and force the new branch to take resources from the graft. This will help strenthen the graft union. As before, I do this by scraping away the cambium on the shoot before the graft and girdling the shoot with a small bit of wire.
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When the graft has taken, you'll notce that the brach after the graft is notably thicker than before. That's when it's time to separate the graft.
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The ones in the picture above were taken after one growing season. You can see that they've been girdled and the bark and cambium has been scraped away below the graft union. There is also good callousing at the union. I could probably have seperated and it would have been fine, but I chose to be sure by waiting through next spring before I finally separated the graft.
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See the scarring? That's an approach graft thing. Here's an important tip. You'll often see folks approach grafting across the grain of the wood.
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This approach can result in some unnatural looking scarring. Branches just don't produce a big bar-like swelling perpendicular to the trunk. This technique can produce a graft union that will always be obvious. Consider instead grafting with the grain - it will still produce a callous swelling, but it will be a lot more natural looking than one cutting perpendicular to the trunk. Especially with pines and junipers.
 

aml1014

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At $18 for 5 lbs is darn cheap and you can pick it up at Home Depot. Not Loews, weirdly enough (at least the one by my house). According to Danny, the difference is Neem oil. Work it into the duct seal until it's as pliable as you like and then store it in a plastic bag.
Great tip, thank you so much for sharing all your knowledge and experience.

Aaron
 

markyscott

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Here's another trap.
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This picture comes from Eric Schrader's blog. It's a successful, but poorly executed graft. First, the scion was grafted perpendicular to the trunk and second, the cut wasn't deep enough. This graft will never look good. It's especially important with junipers to graft along the grain - junipers have a very linear vascular system and cutting a groove perpendicular to the grain can damage a lot of it. Cutting a groove parallel to the grain will minimize the distrubance to the living vein.
 
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Really appreciate the info. I plan to do lot of grafting of various types this season. Didn't know about the neem oil in the duct seal. I have duct seal but I find that it doesn't adhere to well sometimes. Maybe mixing in the oil will give it a better consistency.

Would I be good starting my approach grafts early-mid summer? Spring arrived nearly a month ago here and I'm sure growth will be hardened by then.
 

markyscott

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Really appreciate the info. I plan to do lot of grafting of various types this season. Didn't know about the neem oil in the duct seal. I have duct seal but I find that it doesn't adhere to well sometimes. Maybe mixing in the oil will give it a better consistency.

Would I be good starting my approach grafts early-mid summer? Spring arrived nearly a month ago here and I'm sure growth will be hardened by then.
Hi Bleumeon. If you want to do them this year, do them immediately after the spring growth has hardened off. You have a long growing season there so you should have lots of growing season after the spring growth has hardened. However, if you want to be sure and/or for others living in areas with a shorter growing season, just wire this years growth into place this season and graft next spring right when the buds are about to push. We graft the same time of year we repot temperate trees.
 

markyscott

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Another common use case for approach grafts is when I'm swapping out foliage. That is, when I graft seedlings with more desirable foliage onto a tree with the intention of eventually removing all of the native foliage. Generally, I've done this when I've grafted shimpaku whips onto other juniper species with less desirable foliage. In these cases, I've always cut the dovetail groove into the trunk of the understock and then attached the 4" pots with the seedling scions to the groove. It's important to make the groove deep enough so that the scion can be fully contained within the cut. Then staple it down securely.
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markyscott

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Here's another example. Kishu shimpaku on Sierra Juniper.
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Hard to tell from this picture, but there's a chopstick there and a piece of rubber protecting the outside of the grafted whip. Then the whole mess is nailed down with some hefty staples. As the shoot expands it is forced into the groove - it makes for a smooth graft union with very little swelling or callousing at the graft.

See? Heres the same graft a couple of years later.
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This will be pretty much invisible in a couple more years.
 
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Here's another trap.
View attachment 135538

This picture comes from Eric Schrader's blog. It's a successful, but poorly executed graft. First, the scion was grafted perpendicular to the trunk and second, the cut wasn't deep enough. This graft will never look good. It's especially important with junipers to graft along the grain - junipers have a very linear vascular system and cutting a groove perpendicular to the grain can damage a lot of it. Cutting a groove parallel to the grain will minimize the distrubance to the living vein.
That's a rookie mistake I've been guilty of making.
 

markyscott

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A use case for thread grafting. Here we want to graft roots on the tree rather than foliage. An example might be that we have a tree with a bald spot on the nebari - so we wish to graft roots from a seedling there to increase root density on the tree. Approach grafting also works well for this, but it leaves a more obvious scar.

The idea is like this:
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We drill a hole entering on the side of the tree where we want the roots to emerge. The hole is angled downward so that it exits through the bottom of the rootball. The seedling is then wired so that it passes underneath the root ball and out the other side. When the graft takes, the seedling may be severed leaving the roots as part of the new tree. The advantage of this method is that there are no scars above the soil line and the exit wound is completely invisible.
 
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markyscott

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Clean the edge of the hole with a grafting knife.
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Then pick a bare root seedling and thread it through. Be sure to scrape the bark down to the cambium of the seedling right where you'd like it to make contact with the side of the hole. It should exit underneath the trunk of the tree.
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markyscott

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Make a chopstick wedge and insert it into the hole above the seedlings roots. Firmly press it into the gap, forcing the roots against the bottom of the hole. When the roots are wedged tightly against the side, you can cut the shop stock off flush with the trunk.
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markyscott

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@markyscott I just noticed you put the chopstick fragment above the thread graft, and I've been putting them under. Does it matter?
For root grafts it probably doesn't matter too much. For grafting branches the scion should be pressed against the bottom or side of the hole.
 

0soyoung

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markyscott

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I agree that it doesn't seem to matter much, but I also agree with @garywood and think it is better to have the scion pressed to the top of the hole.
I've been taught to put it on the bottom because sap flow is between the roots and the foliage so this is the position to expect the most rapid callousing. I agree with Gary's point about water being the enemy of grafting and the graft union should be carefully sealed.
 
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