I get a lot of questions and interest about building frankentrees and frameworking. I'd like to do either a book or high quality in depth video either this year or next, but, in the meantime, here are the most important points for success. All of this is covered elsewhere, I just thought I’d put it all in one place with photos to make it more accessible. This is applicable to pears and apples. Plums are also pretty easy and should be more or less the same. Cherries I’ve had mixed luck with, but haven’t worked with them a lot. Most of my cherry trees are still single varietal. for now… For scions check out the North American Scion Exchange trading site. It is awesome! I've also just put scions in my web store. I am mostly sold out for this season, but there are a few left. I should have more quantity and variety next year.
When to graft. I actually don’t know when you should graft. I know what I can get away, but I’m not sure what people in colder climates deal with. And so your journey begins! Go forth and find that out! I can tell you that it’s okay to graft during bloom. Once the tree is really growing vigorously, grafts will still often take, but many times they will not grow much in that season, if at all. They may just actually sit there dormant till the following season. I've grafted dormant scions in July with some success, but they didn't grow until the following year. It is also bad for the tree to butcher it all the way back after spring growth is well underway, so don’t wait too late. Early in the bloom season before growth really gets cranking is still an okay time. I can graft from anytime in February on into spring.
Topworking v.s. Frameworking: Topworking basically means cutting into larger limbs and adding a few scions to each stub in order to grow an entire new top to the tree. Frameworking retains the framework of the tree and adds more scions here and there in order to replace just the smaller branch structure and fruiting wood. The advantages to frameworking are pretty compelling. Quicker fruiting, less trauma to the tree and you can add more variety at one time. The advantages to topworking on the other hand are that it requires less work, less time and fewer scions. A topworked tree should grow back pretty fast, but it will still take some years. If the top worked tree had a good form to start with, then that all has to be regrown and trained with lots of pruning. I think frameworking is usually preferable when it is feasible, and the work can be spread out over years if need be, or as scions become available. In a small home orchard or back yard situation, it is rarely necessary to resort to the brutal practice of topworking.
Graft placement and Tree preparation: Whether the tree is grafted all at once or in stages over years, there are a few points that are important to keep in mind. You want the tree to have a good form that is physically strong, fruitful and easy to manage and harvest.
*Height and shape: If a tree is very large, but has good form, don’t butcher it to make it smaller unless it is of little value for some reason. Trees which are neglected (or never trained at all) and grow into poor forms with a lot of very tall upright sections that are way out of reach without a huge ladder, often need major surgery to bring them down to a manageable height. They will usually need major thinning as well to get an open branch structure. It is important to have light inside the tree. Very dense trees lose the ability to fruit on the inside of the tree and fruit quality is poorer without sun. Keep in mind that the bigger the cuts, the longer the healing time and the more risk of introducing infection into the tree. Big cuts often have to be made though and the decisions are not always easy ones. At some point though, you just have to start cutting.
Take a look at the tree in these pictures sent by reader Joe Holthaus which he inhereted and plans to frankentree. In terms of structural strength, fruit production and maintenance/picking, this tree is poorly trained. This shape is inherently weak, though it may be fine for a long time yet. The top has been cut off mostly at one level 3 or so years previous, probably to bring the height down. You can see where it was cut off and clusters of large shoots have grown up. It has been allowed to grow back freely from the cuts making those tall upright shoots. I would remove most of those new growths at the top, bringing it down to where it was hacked off a few years back. Then graft into the remaining few shoots after shortening them to stubs. After that, if the tree is pruned every year to to shorten the previous year's growth, it can be maintained roughly at that height, like an annual haircut. The branches that do grow horizontal already can be pruned back to stubs retaining the main framework. Sometimes you will retain only the main scaffold branches, and sometimes you will retain side branches too. It just depends. In a lot of cases, most of the wood 1 inch and larger will be retained if it is well placed, and removed completely if it is not. yI would trim those big stubs back to the trunk so they can heal over and prune the suckers flush with the trunk as well. When new suckers grow back in the spring, they can be pulled off early and through the summer as new ones emerge. Pulling them off will discourage regrowth more than cutting them to stubs during the dormant season the way they are in the picture (numerous sucker stubs low on the right hand trunk).
*What to cut off and what to leave. I like to prepare the area or the whole tree and then graft. Whether you are just adding a scion or re-grafting a whole tree or section, you generally need to thin out some competing wood. What I can say that you don’t want to do is keep adding things to the outside of the tree. Lets say I have an apple tree that I like well enough and want to keep, but also want to put on another variety for some reason, like for better pollination or just for variety. Think of the branching structure of the tree more or less as wood that produces fruit and wood that doesn’t. In frameworking, you more or less want to keep the structural wood and replace the fruiting wood. Now this will vary with all sorts of conditions, but generally, larger wood stops producing fruit after a time. I would say that on average I’m grafting into wood between 1/2 inch and 3/4 inch, though not infrequently smaller and larger depending on the situation. If I add just to the smaller wood on the outside of the tree, the tree keeps growing outward and there is a limit to that. It is better to go into the tree a little further. By grafting in closer to the main scaffold branches, you prevent the undesirable phenomenon of the tree creeping ever larger outward, and you also insure that everything beyond the graft is the new variety.
*Thin it out, space and spacing: Thinning of existing wood can be done for several reasons. Many trees just have too much congestion to make good fruit. The tree will produce the best and sweetest fruit if the interior of the tree has light. Air circulation is also good. There is a mindset that natural is always better. When it comes to growing trees, I disagree with that view. The way trees grow naturally works from an evolutionary standpoint, but that does not mean it is ideal, or that it is best for their health, and certainly not for our needs. I've come to see the growth of a tree as an adaptive but somewhat chaotic process in which it basically competes with itself. Just like some of our behaviors, it has served the tree well enough to survive evolutionarily speaking, but it does not serve them best in every case. Left to their own devices, trees will often shade out their own interiors, over compete with themselves, become clogged with dead wood, and very often form weak structures that can break under weather, snow or fruit load.
For our purposes here, we also are concerned with the allotment of energy within the tree structure. More leaf and twig area means fewer resources for each section, branch or twig, so we can direct energy into the new grafts or wherever we want it by removing some wood and leaving other wood. (We won’t get into it here, but you can also do that with bud selection.) So, the short version is this. When you add a graft, remove any wood near it that is not valuable to give the new graft space and direct energy from that area of the tree into the new graft. Thus the graft has less competition, but also gets more light, which will allow it to grow more.
As far as how much room, a good rule of thumb is at least inches apart along the limb on larger structural wood. And not 12 inches on one side, but staggered side to side. So, from one graft measure 12 or more inches and put a graft on the other side of the limb. That way each graft on any side of the limb is about 2 feet from the last. That may seem like a lot, but it is not. Once those new grafts grow out some side branches, they only have to grow 12 inches to the side before running into each other. That is just a rule of thumb. You don’t want bare sections of branch exposed to the sun either, or they will sunburn. And convenient stubs to graft onto never occur exactly on a spacing. So, just think in terms of about an average of 12 inches staggered and it will work out fine. You can do some closer for sure, and put on extra for insurance, but plan on removing some of them later.
To prepare all at once, or gradually?: If the tree is healthy, I have never found it necessary in frameworking to leave any of the old variety to grow on the tree. But then I have a high percentage of success on my grafts and a confidence born of experience. It may be different with very old and weak trees, I don’t have enough experience to tell you that. If the tree is healthy and I have enough scions, I’ll cut everything off. If it makes you feel better, you can always leave a percentage of the old tree for insurance. If you are just beginning at grafting, I would just do some random grafts here and there to get a feel for your ability and how well your grafts are taking. You can then proceed as you gain confidence, and nothing is lost if any graft fails. Even if you go for it though and half the grafts fail, it will probably be just fine. I used a lot of difficult side grafts on the original frankentree and about half of them didn't make it. Even though I had cut the entire tree back, it was perfectly fine. The tree does need something to grow into. It has to produce leaves and gather energy to survive. If a lot of grafts are put on, then it can grow plenty of leaf area pretty fast. In Topworking, where you chop off most of the tree and graft on only a few scions to each stub, “nurse” limbs are often left to feed the tree while it regrows it’s top and those are cut out after a year, or maybe two years. In Frameworking this doesn't seem to be necessary, probably because the tree regrows so much leaf area the first season.
Scion length: I like to use longer scions for frameworking. They have the potential to produce fruit a little sooner. They don’t always do so, but they have the potential anyway and do sometimes. I will typically use scions with 8 or more buds if I have them and up to around 12 inches long. Different varieties will grow in different ways, but typically 2 or 3 buds near the tip of the scion will grow into long shoots and the others will either sit there, grow into short shoots (which sometimes bear at their tips), darts, or fruit buds. Sometimes those extra buds just sit there and do nothing, but at least there is a chance and you can sometimes have fruit the year after grafting. It is fine to use short scions too with only one or two buds if that is all you have.
Bud facings: You can use pruning to choose buds to retrain the tree to grow as you want it to. The bud at the tip of the scion is usually the one that will grow the most vigorously. If grafting on a downward facing branch, you might choose to prune the scion back to an upright facing bud (or just graft it on in a way that the last bud points up) so that the branch will start growing upward again. If grafting to upright stubs, choose buds that face outward into an open space. In subsequent years, you can keep choosing outward facing buds to encourage more spreading growth.
Which Grafts to use: It doesn’t matter too much what kind of grafts you use if they take and grow. I use cleft grafts, whip and tongue and bark grafts for the most part. Bark grafts are made by slitting open the bark and tucking in a scion. They are better for large stubs than cleft grafts because there is no need to split the wood. They also create a lot of cambial contact and that is always good. The bark has to be slipping, but that happens pretty early.
If you need to add a branch in a section of bare wood, you can try a side graft. The branch is cut upward so that water will no collect in the cut. The scion is cut in such a way as to wedge into the side cut and is jammed in forcefully. If done right, no wrapping is needed, but it is probably good to seal the whole area with grafting paint. I do so anyway. The Grafters Handbook, by R. J. Garner is where I learned a lot of this stuff and about frameworking as a distinct concept. http://amzn.to/1pGXG23He also recommends another graft that does not require wrapping called the stub graft, which I have used a little, but am still getting comfortable with.
Wrapping and sealing: Grafts should be wrapped tightly. Especially if the scions are long. You can use a lot of different things. White PVC budding tape, green plastic landscaping tie tape, strips of heavy plastic bags. But, whatever you use, make sure you can put some stretch on it and stretch it as you wrap. wrap several layers up and down the graft area.
I like to seal my grafts along the whole length. At the very least seal the end, but sealing the whole length is easy to do and is good insurance. If you are just experimenting, you can use white glue cut with a small amount of water, or just latex paint. I use Doc Farwell’s grafting wax, which is basically like a very rubbery latex paint. The tree buds are very strong and should be able to push through any of those coatings as long as they aren’t applied just ridiculously thick.
Aftercare: I will usually let the new grafts grow as they will the first year. You can encourage certain buds to grow out into shoots though by notching just above them through the bark and into the wood slightly. Other than that though, I would pretty much leave them alone.
Along about July sometime, you may need to unwrap the grafts. They should be fine by then, but if you live in a very windy area, you may want to rewrap them till the end of the season. Unwrapping and rewrapping is fine. If I don’t want to rewrap, I’ll just cut down the side of the wrapping with the grafting knife and the wrapping falls off. You have to cut into the bark a little, but it will heal up very fast, so no biggie. What you don’t want is to see the wrapping constricting the growth of the branch, so always unwrap before that happens too much.
If a graft fails to take, a shoot will often spring up at the base of the old stub and can be left to grow out for grafting onto in the following year. Otherwise, most growth from the old variety should be removed as it sprouts from invisible dormant buds during the spring and summer.
In subsequent years: If your grafts take and the tree is healthy, it will regain a “normal” look in a pretty short time. Make every cut just above a bud and think about which bud you are cutting to and which direction that will make the tree grow in or if it will make the new shoot grow down, or up. On long new shoots, you can select the buds which you want to grow out into new branches and in late winter/early spring, you can notch just above those to make them extend into shoots for fruiting laterals or for whatever purpose. Notching is a very effective technique on apples.
I can’t go into pruning here. I’m already approaching 3000 words! Some general principals though. You want light and air inside the tree. At the same time, you should also strive to shade the main branches and trunk, because they can be sunburned easily causing necrosis (tissue death) and inviting boring insects (yawn...). cut out or shorten crossing branches and thin out dense growth. Typically, once you reestablish the permanent structural wood you will shorten all new wood each year. Shortening makes future pruning easy and controls the height of the tree. The most important exception being with trees that bear on the tips of shoots like Granny Smith, Kerry Pippin and Bramley’s Seedling. Some of them bear on both tips and on spurs along the branches and others bear almost all on tips of the previous year’s growth. If you prune those tip bearers short every year, you won't get any fruit, but that’s a whole ‘nother ball of wax there.
The above is the information you most need to know strategy wise to successfully pull off frameworking. If you’re just starting to learn grafting, how you proceed is really up to you and the value you place on the tree you are working with. Starting gradually to build skill and confidence is fine, or if the tree is not valuable, you could just go for it. If you start small, you are not likely to do any serious damage. Trees are resilient and adaptive. They are used to being broken by snow, wind and falling trees, ravaged by bears, chewed on by rodents, attacked by fungus and insects. You should not be losing sleep over cutting a few branches back and making some grafts to experiment or practice.
Look at grafting information and practice on some scrap prunings until you can make good fitting grafts that show no light and match up well when squeezed tightly. You can use a sharp pocket knife or sheath knife, or a razor/utility knife if it is of a type that the blade doesn’t wobble. If you want a real grafting knife, this one below is affordable and it is what I use most of the time. Whatever you use, it should be sharp. Learning to sharpen and use a knife is where this battle is won honestly, and those are skills worth having, and that you can use in so many different arenas. Get out there and make it happen! Good luck!