2022- What we've learned about grafting- to trees not rootstocks

I’ve decided to add another topic about grafting this year specific to grafting to trees already established in soil as that is all I do and probably what the majority of you use grafting for. However, with my own experience and I’m sure with many others there will be an overlap of useful knowledge, but failures of grafting onto rootstocks are probably often the result of trying to graft on a tree (the rootstock) whose roots have recently been severely damaged, which skewers the meaning of results related to other aspects involved with grafting.

My nursery, 40 miles north of NYC, has about 500 fruit trees growing in it at any given time- most from one to 6 years old. I buy grafted trees wholesale of a single variety and then usually graft another variety on it to either take over the leader or to become a single scaffold branch. With stonefruit I sometimes add 2 varieties.

The only method of grafting I use is a simple splice (no tongues) held together with vinyl electric tape (I used red tape this year for visibility) and, from near the end of that tape to the top of the scion, I wrap the scion with Buddy Tape parafilm. I put a small piece of Gashell pruning wax over the tips, even though the parafilm wrapped all the way around the scionwood would probably be adequate. I try to match the diameter of the the scionwood to the shoot where the graft is made so as much cambium match occurs as possible, but if I can’t match the wood closely, I make sure that there is close cambium contact on one side of the graft with the entire gap in diameters occurring on the other.

Vinyl tape can be pealed off when bark in not slipping (by the 2nd summer, for sure, but also through
the winter following grafting- bark slips through much of spring). That said, stonefruit growth seems strong enough to never be girdled by vinyl tape and I don’t remember ever having a problem with pears.

All of my grafting is to vigorous, upright shoots- to me anything else just takes too much time to establish- the more growth I get the first season the better. The trees I graft to are well fertilized with ample quickly available nitrogen and free from serious weed competition via wood chip mulch and frequent whacking (every 3-4 weeks through summer.) Their water comes from rain only.

Here are the important things that come to mind I’ve learned in the last few years.

Don’t bother wrapping scion wood with parafilm or anything else to protect from dehydration during storage: I received wood from others wrapped with the stuff and it only complicated doing my splice grafts. If you use a refrigerator without defrost, like a cheap little one made for beer, you only need throw wood loosely in ziplocks (I use freezer bags) and put them collectively in a 2nd small garbage bag with a piece of moist cloth. I push out a lot of the air in the garbage bag and twist the top before putting it in the fridge, each garbage bag containing as many freezer bags as is convenient for storage. The wood holds up just fine- at least if you wait until late winter to harvest it. For years I tightly wrapped peach wood with plastic wrap that caused the buds to rot. Finally the smell of the rotten buds and a high percentage of graft failures steered me from that idiocy.

Don’t worry if the wood freezes in the fridge: My scion-wood fridge is in the basement of my house that we keep very cool. During cold spells the moistened fabric in the garbage bag containing bags of wood sometimes freezes, so I assume the wood does too, but even if it doesn’t, it is OK if the fridge dips below freezing during the storage. If temps stay right near freezing the J. plums wood will be less likely to bud out prematurely- so I error on the side of occasional slight freezing.

Hold off grafting peaches: I wait until just after their petal fall but seem to get good success without obsessing on the perfect temps for peach growth. This year I did most grafting between 5-ll and 5-15 and they seem to be almost all successful and were not damaged by a hot spell with two days of temps in the low '90’s, whether I protected them with foil or not. From grafting at different times, I now suspect anything from 60 to 90 in the days following grafting peaches and other species works fine at this point. I did my peach grafting when latest apples still had open flowers.

Hold off on grafting E. plums too. I’m still sorting out the details on the best timing for them, but right now just before peaches seems right. I don’t seem to get much success grafting them the same time as J. plums, apples and pears.

J. plums, apples and pears are best grafted at or just before first growth and in the following week or two. Apples take a long time for the scionwood to sprout leaves for me so the earlier they are grafted the more they benefit from the trees most vigorous period of growth. When I graft J. plums on an established trees quite early, the growth in one season can be amazing. I’ve gotten 8’ of well branched growth. Then the problem becomes getting that thick branch to more horizontal position and requires cutting a hinge to do so without breaking it. I have to start bending branches of such grafts in mid-summer of the first season- although it’s a compromise. As soon as you bend branches to more horizontal you reduce vigor.

I FORGOT TO MENTION THAT SOMETIMES SCIONS FLOWER AT FIRST GROWTH AND THOSE MUST BE PROMPTLY REMOVED TO SAVE ENERGY FOR SHOOT GROWTH.

15 Likes

I once had an apple scion take 60 days to sprout leaves.

3 Likes

I’ve actually had a scions sit out the first year and sprout the next- once without any parafilm to protect the bark, just a dab of pruning wax at the end- in the following 10 years that one hasn’t grown a whole lot. It even happened once with an E. plum graft.

Here, the problem with normal late sprouting is that aphids and leaf hoppers can go after that most tender growth on the tree so you need to protect young grafts from these sucking insects or the grafts may be killed.

2 Likes

What exactly do you mean by hinge? Do you literally cut the branch where it meets the main trunk then let it heal at the angle you want? I need to get reading on my copy of Arboriculture, I’d probably know this answer if I had already.

1 Like

Duchess D’ Angoulme pear was very slow to grow after grafting. I’m not sure why it sprouted out slowly but it did it on multiple trees.

2 Likes

Hinges are an essential element of techniques I use to train trees. You cut a third into the branch you are bending with several cuts on the side you are bending towards (if you want to learn by painful lesson, try making cuts on the opposite side) The cuts are obviously made where you want the branch to bend, so, generally, at the branches origin and up about an inch apart. If there is obvious weakness from a knot or even small canker on the other side you may break the branch, but you still can save it as long as it doesn’t snap off by securing it with a crutch and bending the branch above the crutch. Once you are experience the odds of this happening are somewhere in the 1-5% range- sometimes it happens days after in a wind or rain.

2 Likes

Some quick things I learned this year. Bigger is better. Bigger scions and/or bigger graft areas. Flowers on the scion slow down growth. Electrical tape works great. As the graft heals, the tape slowly begins to unwind and loosen. I did cleft and bark. Although both worked great, cleft seemed to be the sturdier of the grafts. Grafting is a lot more fun than expected!

6 Likes

Amen to that. I don’t even bother with it when people send me skinny stuff anymore- I just don’t have time to deal with less than easy.

2 Likes

@Robert @alan

I like those tiny scions for cleft and rind grafts. The pencils are great for everything else.

2 Likes

I’ve seen that a couple of times, too. It just happened with a Court of Wick scion, in fact.

1 Like

Same here. Helps to nock just above the scion.

2 Likes

I did roughly 50 grafts. Pencils all the way down to super thin twigs. Only lost 4 sticks (so far), but you can see a massive difference with the stored energy in those pencils.

1 Like

Rehydrating tiny twig scions helps. I’ve had too many small ones show growth then appear to dry out.

Don’t give up too soon. I’ve had grafts take 60 days and then just take off.

If a graft doesn’t take and scratches green, you can regraft it in another place on the tree or another tree.

For me, the same varieties on different trees seem to take off at the same time.

When in doubt, angle the scion a bit to ensure cambium contact.

I write who gave me the scion on the tag. It’s just nice to know.

Don’t put the graft too far out along the branch away from the center of the tree.

I went to my first grafting class and scion swap. Those scions were plentiful and did great.

7 Likes

Another example of required patience. An asian pear I grafted in March, over 60 days ago, was showing its first sign of green this morning.

2 Likes

I changed one sentence in my original post- it should have read like this when I first put it up.

Here are the important things that come to mind I’ve learned in the last few years.

Don’t bother wrapping scion wood with parafilm or anything else to protect from dehydration during storage:

I failed to include the last two words which must have been confusing to at least someone.

4 Likes

Indeed, it was. Thanks for the clarification.

1 Like

There is one other thing I learned but failed to mention- that is that grafting chestnuts appears to be easy, which is great because I get a lot of volunteer chestnut trees that I can now sell as named varieties with great tasting nuts. I’ve been depending on other nurseries for such trees.

I grafted the same time as I was grafting peaches, shortly after they had begun to grow. I was surprised how quickly the scion wood began pushing leaves and all 4 grafts I made took. Same simple splice grafts.

1 Like

Unfortunately Chinese chestnuts are prone to delay graph failure and especially more so east of the Mississippi.

1 Like

I assume this is based on your own experience. I was worried that my celebration might be premature, but if they were any other species I have experience with, they’d be past the point of great risk of failure. Ultimately, I will believe what I see with my own eyes and report the results. When does this delayed failure usually occur, in your experience?

Hi Alan the statement I made was not based on personal experience but rather information I collected in research before I started my. C.Chestnut orchard. Any Chinese Chestnut orchardist would be privy to this information.
There is a small percentage of grafted trees that may do well in the long run, but anecdotal evidence suggests even if a graft looks good for several years, decline eventually sets in… the first sign is usually sucker formation demonstrating the rootstock rejection… loss of vigor poor production decline ect and eventually death above graft. For this reason it probably wouldn’t be a good idea to sell them at least without explaining this but it wouldn’t hurt to do a few in the backyard.
There are some assumptions as to what this is but they still haven’t figured it out but I think most authorities believe it is blight/ fungal related.
I also think The best chances for successful Chinese Chestnut grafts long-term is by grafting a parent tree back to its seedlings or siblings. This to has some anecdotal evidence and this is the route that I will attempt as I’ve located a great tree in my zone 20 minutes from my farm. I’ll plant seedlings from this mother and pick the best amongst these and graft them to its siblings.
The" I thinks" above are opinions based on information I ascertained through highly experienced Chestnut orchardist most notably Greg Miller from route 9 Chestnut cooperative in Ohio.

1 Like