OK I had a bunch of persimmon grafts start growing, get a few inches long with several leaves; then unexpectedly either die off at the tips of completely fail.
WHY
Anyone have similar problems with grafting anything and how can it be avoided?
One possibility: Most scions will break bud if warmed. You can even get leaves. There is no graft required. [I tried rooting some mulberry cuttings once. I got beautiful growth for a week or so, then death. No roots whatsoever.] So if this growth happens quickly, before callus formation, the scion gets no support from the rootstock.
So basically we have to hope that a callus forms quickly before the scion starts growing. It seems to me that if a species, such as apple or pear, can form a callus at low temperatures then the probability of success is high. But if a species, such as persimmon or mulberry, cannot form a callus unless temperatures are high then the probability of success is low (or at least lower). At high temps, it becomes a race between callus formation and scion growth. If the scion wins the race, it dies.
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Well explained, thank you. I have also one persimmon graft that I thought had taken, but then the tip died off. A couple more look more promising, bud swelling and no growth yet. Lets see
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@Ariticu … watch out for persimmon graft new growth… to get hit by psyllid attack too. Little white sap sucking critters.
They love the new tender growth shoots from persimmon grafts. They will cause the leaves to curl along the edges and the whole leaf to shrivel.
My one graft of Saijo out on my orchard got hit hard… and so did my graft of Dar Sofiyivky.
When I first noticed them… I started spraying them weekly with Sevin spray.
The new growth is back to looking normal now.
TNHunter
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If the rootstock is a small bare root or potted tree, you can use a hot callus pipe to warm the graft while keeping both the root stock and the scion above the graft cool. I tried this technique for the first time this year and the results were outstanding. Temperature near the grafts was ~80 F, whereas the surrounding air in the garage was ~50 F. See the thread on Hot Callus Pipe.
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If the rootstock is a large potted or in-ground tree, the best bet is to wait until the rootstock tree is growing well and outside temperatures are consistently warm. Here that would be late May or June. Meanwhile keep the scion wood in a cold fridge so it starts dormant.
OR – If you want to be innovative and don’t mind some work, I suppose you could use a warming cable (or similar) to warm the graft even on a large potted or in-ground tree. So instead of bringing the tree to the cable, you’d be bringing the cable to the tree.
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Got a pic of my Saijo graft today.
See those lower leaves … how they are all messed up, edges curled… Psyllid damage… they can absolutely cause a graft to fail here.
Sevin spray will take them out.
Newer growth looking good.
TNHunter
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Nice work. Hate the flies and this year I’ve got some little back beetle chewing holes in the new leaves.
I’ve heard about using heat on grafts but don’t know how to do it. What are you using for a heat source please?
PS Most of these trees are volunteers out in the woods so no way to get heat to them.
As @jrd51 described, it is easy for a scion to get ahead of itself and die back before it can callus enough to survive. But sometimes, if there is a second or third bud on the scion that hasn’t pushed, it may still have a chance.
For most grafting, I’m happy to graft with a single bud on a piece of scion, but for persimmons I often do 2 or even 3 buds in case this happens. I grafted a few small trees with some very thin scion that may have been cut close to when the tree was waking up. After grafting, the temps didn’t warm up as I had expected and the little trees didn’t callus enough before pushing the first bud. But after that first bud pushed and then dried up and died we got enough warm weather and there was enough life left in the remaining bud that hadn’t pushed yet that 2 weeks after the first buds died, the second one is waking up and hopefully this time the trees have enough callus to sustain them. In this picture you can see the dried up growth on the left and if you look closely the top bud is now pushing.
This one (out of focus) you can see is further along.
So if you have remaining buds on a scion that has died back it may still make it.
For the heat source, here’s a rather long thread that covers creating a hot callus pipe: Hot Callus Pipe DIY
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OK Makes sense that the scions grow before the graft is healed. Here is what I observed this year. The more shade was over the persimmon tree; the better the success! Along those same lines I’m thinking leaving the grafts inside their padded envelope, and letting them slowly grow out the top also helps.
Next year I’m not going to remove the padded bags until the graft is growing strongly out the top of the cut open padded envelope. We’ll see if that added shade and humidity helps keep the new shoots alive long enough for the healing process to complete.
These grafts were all done on wild 4-8’ trees wherever they occur on my land.
Thanks to everyone for all the great advice and information.
Larry
Moreland GA
zone 8a
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