tree surgery

Tough thing when starting an orchard is deciding what varieties to choose from among the literally thousands available. If you’re lucky, there is a grower near you selling lots of different types that you can sample, or maybe at least a grocery that stocks more than the standard fare of overwaxed, underflavored commercial varieties. Otherwise, you’re left with the prospect of choosing your trees based upon descriptions in nursery catalogs, which to me often have a certain ring more akin to used car sales: “BEST VARIETY EVER! EXPLOSIVE FLAVOR! BEARS BUSHELS OF FRUIT IN THE FIRST YEAR! IMMUNE TO INSECTS AND DISEASE! HARDY TO THE ARCTIC CIRCLE! KEEPS IN THE REFRIGERATOR FOR SEVEN YEARS!”, and so on. Having been down that road, I can assure you that if it sounds like hype, it probably is to some degree, as there are going to be tradeoffs with any given choice. A further difficulty comes with trying to balance your choices based upon flavor with those based upon more practical characteristics, such as suitability to your soils and climate, or resistance to common diseases, such as apple scab or fire blight. And I won’t even get into discussing rootstocks here, which bring an array of their own characteristics into the mix, and can give you anything from a tree that matures at 35′ tall and might live for 200 years, to one that is mature at 5′ and can be grown in a pot.

When I first started working with fruit trees and realized how many distinct ‘antique’  or ‘heirloom’ apple varieties had been lost over the past century with the industrialization (and more recent globalization) of fruit production— thousands of apple varieties in the U.S. alone—I became a knee-jerk advocate for them, sometimes at the expense of common sense. I’ve since found my way to the middle ground, as there have been some truly outstanding ‘modern’ varieties developed by university breeding programs— bred for flavor, storage, hardiness, and pest/disease resistance—AND because some ‘old-time’ varieties are unheard of today for a reason: they either are pest magnets, or have no flavor, or bad flavor, bad texture, etc…….Of great help to me in narrowing down the options has been the Fruit, Berry, and Nut Inventory (4th edition), published by Seed Savers Exchange, which lists and describes 8,750 varieties. Ultimately, you just have to make your most educated guess as to what will grow and produce well in your region, as sometimes a variety that is astoundingly productive and flavorful in one area produces poorly or is far less palatable somewhere else—even somewhere nearby, depending upon soil fertility and drainage, microclimate, available sunlight, presence of pollinators, preexisting pest and disease populations, and so on.

If you do find yourself in a situation where you have chosen or inherited a tree that produces poor quality fruit, the good news is that you don’t have to go back to the drawing board, waiting (again) for years while your new tree comes into bearing age. Instead, you can upgrade your existing trees with some simple surgery, incorporating as many new varieties as you like, while retaining the use—and the vigor—of the pre-established root system. The two basic techniques of ‘topworking’ a fruit tree are grafting and budding. I’m going to limit this discussion to the former, as now is the time for grafting here in upstate New York. Specifically, the rest of this post will illustrate one type of grafting, known as the cleft graft, which can be used to radically overhaul an existing tree.

gold rush apple treeThe photo above shows the lower half of a Gold Rush apple I planted a number of years ago (on M-7 semi-dwarfing rootstock). It’s a good apple, a more ‘modern’ type bred from Golden Delicious, with significant disease resistance and long storage life, but not my favorite. I had planted two in my orchard, and decided last fall that I wanted to rework one of them this year. So maybe a month or so ago, when out pruning, I cut a number of pencil-sized branch sections from a Fuji that is growing elsewhere on the property (one of my favorite varieties, which amazingly enough was bred from that dreadful excuse for an apple named Delicious, crossed with a rare 19th century variety known as Ralls Janet), and put them into a ziploc bag in the refrigerator with a few drops of water. These cuttings, which are known as scions or scion wood, are generally taken from last year’s growth, although occasionally two year old wood can be used. They are genetically identical to the parent tree—they are the parent tree, really— so can be used in topworking to propagate that parent elsewhere. They must be cut while still dormant, and either used immediately or stored in such a way to keep them from drying out (hence the refrigerator). It is vital that they have a number of dormant buds along their length—a branch tip with the terminal bud is desirable but not mandatory.

The other half of the grafting ‘equation’ is a suitable rootstock—in this case my M-7, with the Gold Rush crown removed:

topped apple stem

In this situation, the tree will end up with three different genetic identities: the M-7 rootstock at the bottom, the Gold Rush section of stem—which sits above the point where the original tree was grafted low on the rootstock (technically known as an interstem)—in the middle, and the Fuji on top. It seems somewhat sad to ‘decapitate’ a tree in this way, especially the first time, but with a superior tree as the result, it is worth the effort, and with practice the rate of success is near 100%.

After making the topping cut, the next step involves making a split or ‘cleft’ vertically in the top of the cut stem, into which a pair of scions, cut into an elongated ‘V’ shape on the lower end, are wedged:

cleft graft

cleft graft

The key to this entire operation is cambium contact—the green, living tissue of the scion wedge must align with and touch that of the rootstock, or nothing is going to happen, other than that the scionwood will dry out and die. In the case of a cleft graft, what this means is that two scions are inserted at the outer edges of the cleft, where their outer edge of cambium can come into contact with the cambium at the outer ends of the cleft (obviously any scion inserted into the middle of the cleft would be useless, as there is no living tissue there—an interesting reminder of how little of a tree’s mass consists of live cells). I use grafting tape and wax to cover the cleft, which keeps things moist until the magic starts and you can see the scion buds begin to sprout, at which point you’ve got a new tree. The new stems will generally grow at an astounding rate, often as much as 4 feet in the first year, depending on the size and vigor of the rootstock, as all of the energy in those roots will now be directed into those two little sticks at the top. After a few years, once the tree has healed over the cleft with new wood, one of the two ‘leaders’ is usually selected as the main stem, and the other is pruned away.

waxed cleft graft

This technique can be used to rework an entire young tree, as I’ve done here, or can be selectively used to topwork sections of a much larger tree, such as might be found in an abandoned orchard. I was awestruck the first time I grafted successfully—still am amazed by it. Right now I’m looking forward to harvesting many bushels of Fujis in the years to come.

One Comment on “tree surgery

  1. Love, love, love this post! I am inspired to try this, although most of our good apple trees are very big and have good heirloom apples that are good for eating, cooking and storage…

    Thanks for a great post! Will be looking for the right type of wax and so forth so I can try it!

    It is amazing that trees will accept the flesh of a new type of tree. That is really cool. I wonder if this evolved in response to some evolutionary process… Did a tornado shear off a nearby branch and lodge it into the bark of a nearby tree? He he he! That would be strange but I am sure it has happened somewhere, given all the time that has passed as trees have been on this planet.

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