How do you know when a graft has taken and is successful?

General Fruit Growing
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If I do a graft on rootstock, how do I know if it is successful? Other than the scion not falling off, is it just matter of see if new growth occurs? If the new growth occurs is all danger of failure gone or is the union still fairly brittle?

I wanted to practice grafting, and I thought if I did want the tree, I could sell it, but I don’t want to sell something that will fall apart in six months.

Edit:. I tried to switch to grafting topic but couldn’t.

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I had a few fail this spring. (do not use just parafilm to wrap, lesson learned). You can see it leafed out a bit before dying. If it really starts pushing growth, it should be good.

failedgraft
failedgraft694×720 569 KB

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There isn’t a set time, I’ve even had grafts that didn’t take the first season end up sprouting out and succeeding the 2nd. I would say that generally, once growth is truly vigorous you are home free because at that point the callous is strong. I’ve had grafts that started growing fairly well die as a likely result of leaf-hoppers sucking the life out of them- they are vulnerable because they are still tender and green when all nearby foliage has toughened up.

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Hi John,
The best book I have found for grafting and other plant propagation knowledge is “Hartmann and Kesterson Propagation Guide” Your local County library may have it. You will know only after vigorous growth is sustained. Often there is good energy and the buds break out but if this occurs before the graft union is formed, it will likely fail, since the union is required for flow of nutrients between scion and rootstock.
This weekend I summarized from Kesterson the following critical points that you may find helpful:
Dennis
Kent, wa

Summary of Kesterson and Hartmann’s grafting guidance:

For a successful graft you need:

  1. Compatible rootstock and scion.
  2. A good match of cambium layers where the callus occurs.
  3. Pressure to hold the pieces firmly together, preventing any movement during wound healing, that typically should occur over a 2-3 week period.
  4. Proper sealing of graft to prevent desiccation.
  5. Care of the graft before and after bud break, to control temperature and to protect from other environmental elements, such as bird landings. Callus formation is required at the graft, therefore temperatures are only needed at the graft. The rootstock and scion can be held at lower temperatures to avoid breaking the dormancy. Very often it is helpful to cover the graft with aluminum foil, shiny side outward to prevent overheating. Cover so that the graft gets only indirect light to encourage bud growth.
  6. The entire graft and graft union must be sealed. Parafilm is usually the best, but often does not provide enough pressure at the graft union to assure good cambium contact, so I usually use a stronger plastic or rubber, or rubberized electrical tape to tighten the graft union after applying parafilm.
  7. The timing of your graft often is the most critical factor. Grafting is usually done just before the rootstock is breaking bud, although done later on certain fruits like peaches, pawpaw, and persimmon once the plant is leafing out. Given that you have a limited amount of energy stored in each scion, you do not want bud break to occur until a strong union is obtained allowing nutrients to flow between rootstock and scion. The order of callus healing usually involves Xylem, then Phloem, and then the Cambium bridge matures. The following temperature guides give you the best times for various types of fruits.

Callusing temperatures of Fruit and Nut trees

Posted on May 21, 2013 by qwertyqweryt61

Many people ask me what are optimum callusing temperatures to ensure a good percentage of viable grafts.

Nectarines/Peaches – 18-26 deg C. ( 64.4 to 78.8F)

Apricots/Cherries – 20 deg C. ( 68F)

Plums – 16 deg C. ( 60.8 F)

Apples/Pears – 13-18 deg C. ( 55.4 to 64.4F)

Walnuts – 27 deg C. (80.6 F)

Grapes – 21-24 deg C. ( 69.8 to 75.2 F).

Do not forget tissue damage for most temperate fruit will occur at temperatures over 30 deg C. (86 F)

Temperatures either side of the optimum will also work, but the percentage take will be reduced. See graph below for walnuts.

callus_graph.jpg

Callus graph showing optimal temperature range

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Most of my grafts are a couple years old now and growing strong, but I still occasionally wonder if they’ve “taken!”

As @alan and @matthew say, once it’s growing strong, it’s probably going to be fine. HOWEVER, if you sell a graft that’s taken, you need to be clear that it’s a bench graft and not an established tree. First year grafts need more TLC and delicate handling than one that’s been growing for a year or two. The rootstock may still be trying to grow (and can outcompete the graft) or a bird can perch on the tree and break the still-mending graft union if it’s not staked.

IMO, the best way to practice grafting is to

  1. Read up on everything you can and watch some videos. If you have access to a class, even better. Don’t worry if it doesn’t all click, it will start to make sense as you do physical practice.
  2. Get a bunch of dormant sticks (ideally whatever species you’re grafting, but anything will help you get the idea) and just practice your cuts, then practice putting two cut pieces together, then practice wrapping them. Trust me, you’ll be much happier if you get your mistakes out of the way on sticks you don’t care about instead of on that ultra-rare heirloom apple you had to go on a vision quest to track down.
  3. Repeat steps 1 and 2. You’ll see things you missed in your first reading and have a different understanding of others. And do a post-mortem on each practice cut to see what went well and what didn’t. This will help you adjust and improve, instead of just cementing bad habits.
  4. Finally, try it out for real! It’s a little scary when the rubber meets the road, but if you’ve been practicing and paying attention, you’ll probably be ok. The only other thing to remember here is that temperature matters. Check out @DennisD 's post above.

There are a lot of good threads on here for general grafting advice and troubleshooting. I highly encourage you to check those out. And don’t get too discouraged even if it doesn’t work out the first time. It’s not rocket science, but things can go wrong, and everything’s a learning opportunity. Good luck!

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I will add, I found out (the hard way) that even with extensive growth, you’re not home free, clear sailing. I had top worked, using bark/rind grafts, approximately 30-40 wild crabs this past spring. All but two or three took and from leaf out to late July/Aug, had put on anywhere from 2’ to 6’ of growth (I was tickled pink to say the least with my first attempts of grafting). I had used electrical tape (sticky side out) to hold the graft unions. A few were showing signs of possible girdling (or at least tape was starting to restrict growth) so I removed tape from all the grafts. A thunderstorm later in the week broke 7 or 8 grafts off right at the union. Heartbreaker. I re-wrapped all the grafts at that point and figure I’ll leave them wrapped until late next spring when they start showing signs of the tape restricting them.
I would think whip, whip & tongue, and cleft grafts would be a bit more secure after some growth of the scion compared to the bark/rind graft, but just a heads up to keep an eye on them!

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I’ve started to use rubber bands over the parafilm to secure the graft after having a couple grafts break. Before placing the scion into the graft site, I place the rubber band on the rootstock and wind it around the branch until it’s tight. Put the scion into place, wrap with parafilm, then gently roll the rubber band up over the graft site. By the end of the season the rubber band has deteriorated and fallen off on its own.
-This technique was stolen from some YouTube video, but I’ve since forgotten which one.

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A lot of good points here, Jason’s technique reminds me of some of my girdling failures, rubbers do an excellent job of cinching up and pulling together the scion and rootstock as well stabilizing the graft. However, it’s a good idea to verify about 3-4 weeks after grafting that it is not girdling the limb. Once the graft is actually growing, I usually remove the rubbers and leave the grafting tape to keep the union secure and sealed. I find it much easier to seal the scion with parafilm before grafting leaving enough parafilm at the basal end to cover the graft union one I have made the joining cuts, then I stretch the parafilm around the graft union before I apply any other stronger tape or grafting rubber. I usually then cover the grafting rubber with plastic tape wrap to prevent deterioration during the callousing period. Once the callousing period is complete, remove the rubber to avoid girding and to allow the graft union to expand in diameter.