Introduction: Grafting a Multi-variety Apple Tree.
Imagine having a single apple tree with a dozen or more apple varieties! An orchard, all on one tree!
In this instructable, I'll show you how to do two types of grafts; the cleft graft, and the whip and tongue graft.
Why create such a tree?
- Multi-grafted trees are perfect for small back yards where you may only have room for one tree.
- They solve the problem of pollination, because the different varieties pollinate each other.
- You get lots of variety.
- By grafting it yourself, you can decide exactly which varieties you want.
The secret is a technique called grafting. Actually, it's not a secret. Grafting has probably been practiced for thousands of years, and it's not that hard.
I'll be focusing on apples, but most fruit trees can be grafted using similar methods. Apples and pears are easiest, while stone fruits like cherries, plums, and peaches are considered a bit more challenging for beginners. Just remember you have to graft the same species together.
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Step 1: What Is Grafting? and Why Graft?
WHAT IS GRAFTING?
Simply put, Grafting is taking a cutting from one tree, and attaching it to another tree. They will heal together and grow as a single plant.
To accomplish this, we take advantage of the remarkable ability of plants to heal. Imagine if you accidentally cut off a finger, or an arm, and you could just tape it back on, bandage it up, and it would reattach itself.
Trees can do that.
Now imagine you and your friend could trade arms. You cut off your arm, your friend cuts of their arm, and you bandage your friend's arm onto your stump, and vice versa.
Trees can do that too. the twig generally has to be from the same species, but it can be a different variety (or cultivar) and it will still attach and grow.
So a Macintosh apple twig can be grafted to a honeycrisp apple tree, but you can't graft a plum twig to an apple tree.
When a tree produces fruit and seeds, those seeds won't grow into a tree identical to the parent tree. Just like you aren't identical to your parents. So if you plant a seed from an apple, it will grow into a tree, but the apples from that tree will not be identical to the original apple. Often they will be small and inedible "crab apples". Occasionally you will get lucky, and the seed will grow and produce tasty apples.
By grafting, you can take cuttings from that lucky, tasty apple tree, and clone it, producing an almost infinite number of copies that will produce identical apples.
This is how all apple varieties originated. People planted a bunch of seeds, grew them into trees, and picked the best ones. If you have acres of land and lots of time, that's an option, but with grafting you know exactly what you'll get.
Step 2: Plant Anatomy (it's All About the Cambium)
Trees have a thin layer of vascular tissue, just under the bark, called cambium. The cambium delivers water from the roots up to the leaves, and delivers sugars from the leaves (which are solar powered sugar factories) down to the roots. If the cambium is damaged, it will try to heal itself, but the cambium of scion and stock must be in close contact for this healing to be successful.
The key to a successful graft is getting the vascular systems of the scion and stock to match up and heal together quickly, before the scion starves or dries out. The scion has just enough stored sugar to survive for a week or two, and even start opening it's buds, but if it dries out, it will quickly die.
If there is a small gap, the cambium will produce scar tissue (called "callus") to fill the gap, but this takes time, and the clock is ticking. The wider the gap, the longer callusing will take, and the scion may not survive that long.
Sometimes a scion will look fine at first, with buds opening and leaves growing, and then it will suddenly dry up and die. This is because it used up it's stored water and nutrients before the cambium could heal, usually due to poor cambium contact or misallignment.
Take a piece of practice wood and cut through at an angle. You will see a thin layer of green, just under the bark. that's the cambium. In some apple trees with red leaves (usually ornamental crab apples), the cambium, or even the wood itself, may be red or purple.
Step 3: Materials You Will Need
- Rootstock, or an existing apple tree from a nursery, or in the ground already.
- Scions of the apple varieties you want to add
- Sharp pruners or a fine toothed saw. Pruners work fine for smaller grafts (< 1cm). Saws are best for larger diameter grafts.Pruners and saws must be sharp or they will crush and shred the cambium.
- A knife, with a thin, straight blade. Box cutters or utility knives work, and they sell grafting knives that are fantastic. True grafting knives are only sharpened on one side. The other side is perfectly flat. it should be very, very sharp.
- A grafting tool. This automatically cuts the scion and rootstock like puzzle pieces that fit together. Some people love them, others don't. Probably worth a try, although I haven't used them. I've heard the blades can be a bit dull, and hard to sharpen because they are curved. Some also cut "chip" grafts.
- Materials to wrap the graft. preferably something non-stick, and stretchy. Here are some options:
- Parafilm. Its a stretchy waxy paraffin tape that seals in moisture to prevent the scion from drying out. its non-stick, but sticks to itself. I use this as the inner layer of wrapping.
- Rubber splicing tape. (available at many hardware stores near the electrical tape) look for 3M Temflex. It has no adhesive, but sticks strongly to itself. I use this as the second layer, over the parafilm.
- Other materials. People use all kinds of things to wrap grafts, ranging from masking tape, electrical tape (sticky side out), strips of plastic bags, special grafting tape, and wide rubber bands. In the old days they wrapped grafts tightly with twine and painted melted wax onto it.
- Grafting sealer or wax (optional): There are lots of types. some people use latex paint, or toilet ring wax. Others use special grafting sealers that can be brushed on. This may be optional on smaller grafts, especially if you use parafilm and wrap the graft thoroughly. It's necessary on larger cleft and bark grafts.
gloves. preferably tight and thin, but tough. This provides a little protection from cuts, and you may be grafting in cool weather,
A spray bottle of rubbing alcohol to sterilize your tools or a bottle and a clean cloth. (You don't want to spread diseases between your trees).
- A first aid kit. Or at least some bandaids. Just in case you cut yourself, which you probably will, eventually.
Step 4: Find Scions and Rootstock.
A scion is a young twig, cut from a tree. This can be grafted onto rootstock, and will grow into a tree or branch and produce fruit. Scions are cut during winter, when the tree is dormant, and kept refrigerated and wrapped in plastic bags to keep them from drying out. They are usually grafted in early spring, just as the buds begin to open.
Where to find Scions
When starting out, it's probably easiest to buy scions. Do a quick search for "apple scionwood" and you'll find lots of sources online. They are usually about $5 each. There are hundreds of varieties easily available, of every possible type, and thousands of varieties if you're willing to hunt around. A typical scion is about 8-10 inches long, and will have about 8 buds. You really only need a few buds per graft, so you can cut it into several pieces and graft each one separately, or graft the whole scion as one piece.
Collecting and Storing Scions
Scions are usually collected in late winter, when the tree is fully dormant. If you buy scions, they will probably arrive in early or mid March. Scions need to be refrigerated until you graft them. I usually wrap them completely in parafilm and double bag them in zipper bags. This keeps them dormant. keep fruits and tomatoes away from them. It's best not to have any in the fridge if possible, and definitely don't have any in the same drawer. Ripening fruit emits ethylene gas, which will cause the scions to sprout too soon.
Rootstock is the trunk and roots that you graft the scion onto. The roots influence the growth of the rest of the tree, including it's size, growth rate, and fruit production. Rootstock varieties roots that have desirable traits, like disease resistance, dwarf size, cold tolerance or early fruit production. If you want a dwarf tree, you need dwarfing rootstock. It is possible to simply plant apple seeds and use those seedlings as rootstock, but they will be standard sized trees.
Where to find rootstock
You can buy rootstock and graft onto it, or buy a young tree that is already grafted onto rootstock, and add more varieties onto that tree by grafting a few onto branches each year. You can even take an older tree and "Top work" the tree by cutting off branches and grafting onto the stumps.
Rootstock usually is bought in bundles, but can be bought individually. Rootstock costs $3 - $5 each, or even less if you buy in bulk. so you can graft a single variety tree for about $10-$15, and each additional variety is just 5 bucks more. A quick google search for "Apple rootstock" will find places to buy them
If you buy rootstock, it will be shipped in late winter, and will be "bare root". This is a dormant tree with the soil rinsed off the roots, and wet paper or moss packed around them to keep them moist. it's generally best to pot them temporarily until you graft onto them.
Grafting onto existing trees
Remember that you can graft onto any apple tree, including crab apples.
So if you have a crab apple tree in your back yard, you can "top work" edible varieties onto it.
You can graft onto any apple tree you buy at a nursery. every nursery tree has been grafted already, when it was very young. You can usually see the graft union near the soil line. Everything below that is the rootstock, and everything above grew from the scion. If you look at the tag, it should indicate what rootstock was used, or at least what size. I would caution against buying any apple tree that doesn't indicate what rootstock it is on.
You can even buy trees that already have multiple varieties, but the price is steep, usually around $50, and you have little choice about the varieties they choose.
Step 5: Where to Start
DECIDE WHAT YOUR GOALS ARE
First you need to decide what kind of tree and apples you want.
- SIZE: This is determined mostly by the root stock, and by the way the tree is pruned. The larger the root system, the larger, longer lived, and stronger the tree, but smaller trees often fruit earlier, and devote more of their resources to fruit production, rather than leaves, branches, and roots. The sizes listed here indicate the size without pruning. Any of these can be maintained at a smaller size if you carefully prune, although it might take quite a bit of work to keep a standard tree limited to dwarf size.
- Standard sized trees grow quite large; up to 25 feet tall and wide. you would need a tall ladder or a long fruit picker to harvest fruit from the mature tree. They take at least 5 years (or more) to begin fruiting, but they are very long lived. if you grow a standard sized tree, it might still be alive in 100 years, or more. They are also free standing, and require no staking or irrigation, and minimal fertilizing.
- Semi Dwarf trees are almost as large as standard trees. They are sometimes called semi-standard. They may reach 15-20 feet tall. The advantage is that they produce fruit at a younger age, and are usually free standing and relatively long lived, but not as long as standard.
Dwarf rootstocks produce trees around 10 feet tall that you can pick without a ladder, or maybe with a short step-stool. They have smaller root systems that limit the size of the tree, but they usually need to be propped up with stakes, and irrigated, and they don't tend to live as long (around 20-25 years). If well irrigated and fertilized they fruit at a very young age, and can be very productive.
- Fresh eating: Taste good without cooking or sweetening, but "tasting good" is a matter of opinion. Some people prefer sweet, mild apples, others like some tartness.
- Pie apples: Hold their shape when cooked and don't shrink or get soggy. They are often tart and need sweetening, but have great apple flavor. I know people who eat super-tart pie apples like candy, but the average person would find most pie apples too sour to enjoy fresh.
- Sauce apples: Cook down quickly into sauce. may or may not need added sugar.
- Cider apples: Used for hard cider. most hard cider is a blend of different types, to achieve a balance between sweet, tart (sharp), and bitter (tannic). Many cider apples are only good for cider and are almost indedible otherwise.
- Multi-purpose: Many apples can be used for more than one purpose, but very few can be used for everything. Multi-purpose apples tend to be good for fresh eating and cooking. Some can make cider all by themselves, and are edible.
Crab apples are just small apples. many taste terrible, some are good for jams and jellies, or can be used in cider blends. A few are delicious for fresh eating.
- Sugar or "Sweet" apples were grown for refining into sugar or mollases, or fed to livestock. They are sweet but bland, with very little apple flavor or tartness. Tolman sweet is a good example. Red delicious probably fits into this category.
- RIPENING SEASON and storage. if you choose the right combination of apple varieties, you can have apples from late July until November, with storage apples in the fridge until next spring.
- Early apples. Ripen as early as late July or early August. They don't usually keep well, and must be used promptly. Many, like yellow transparent, tend to be more tart and less sweet, but excellent for pies or sauce. If you want early apples for fresh eating, some of the edible crab varieties like Trailman are both early and deliciously sweet.
- Mid-season apples. Ripen in late september or early-mid october.
- Late apples. Ripen in late October or November. some will hang on the tree into December. They tend to keep well, and many kinds require a period of cold storage to develop their flavor.
Step 6: When to Graft
The types of grafting I'm going to teach you happen in early spring, just as the buds are opening and the first tiny leaves emerge. The old saying is "graft when the leaves are the size of a squirrels ear".
I'm assuming you don't have a squirrel handy for direct comparison, so lets just say fingernail sized.
Some people graft earlier, before the buds open, and they seem to be succesful too. Anywhere in that range is probably fine.
Step 7: Where to Graft
It's best to graft onto younger wood when possible. I prefer small branches directly off the trunk, or vigorously growing vertical "waterspouts".
Step 8: The Cleft Graft.
This is probably the easiest style of graft. It is often used when the understock (rootstock) is larger than the scion, but it can also be used when they are the same size.
The disadvantage is that it's a bit messy looking.
The scion is cut to a wedge shape, and the under-stock is split. The scion is then wedged into the split. to ensure complete healing, the cambium on both ends of the split must be grafted. on large diameter stock, this may require to pieces of scion wood.
- Gather your materials and scions. have everything ready.
- Find a site to graft onto. It should be the size of the scion, or larger.
- Saw or prune off the understock branch, leaving at least 8 inches or so.
- Split the branch stub carefully with the grafting knife. hold the crack open with a toothpick, inserted in the center.
- With the grafting knife, carve the scion to a 2 inch long wedge. Be sure the cuts are flat, not curved.
If the scion and stock are the same diameter:
- Gently wedge the scion into the stock. Make sure the cambium lines up as much as possible.
- Wrap the entire graft area with parafilm. Gently stretch the parafilm before wrapping. One layer is fine. Be sure to completely wrap the graft to seal in moisture.
- Wrap over the parafilm with rubber splicing tape, such as temflex, or with a wide rubber band.
If the stock is slightly larger than the scion
- Split the stock branch just off center, so that the split is the same length as the diameter of the scion.
If the stock is more than twice as wide as the scion
- Insert two scions in the same crack, so that the cambium lines up on one side of each scion.
The following spring, after the scions have grown, you will prune off one of the scions. That one is just there to fill the crack in the stock and ensure healing.
Step 9: The Whip and Tongue Graft
This graft works best for scions and stocks of the same size, but it can be modified to accommodate stock that is slightly larger than the scion.
This is a modification of the relatively simple (but not as strong) whip graft. In a whip graft, the scion and stock are simply cut at an angle, and taped together.
We can make this more stable, and much stronger, by cutting a slit in each piece, and wedging the "Tongues" into the corresponding slits.
This is sometimes incorrectly called a "bench graft" because it is often performed on young, dormant, bare-root stock, while sitting at a bench. But really, any kind of graft could be used for bench grafting. you could bench graft with a cleft graft, for example.
- Gather your materials and have them handy.
- Find a site to graft onto. Prune it off a bit longer than you need it to be.
- With the grafting knife, cut the stock and scion at the same angle. the cut surface should be about 1 1/2 inches long. The cut surfaces should be flat, not curved or uneven.
- To cut the scion, hold your thumb against the wood, pressing the wood against the blade with your thumb. Your thumb should be next to the blade, but not in the path of the blade edge.
- Hold the scion and knife close to your chest. Hold the blade still, and pull the the scion away from you. This is much safer than pulling a sharp blade towards yourself.
- Cutting the stock can be more challenging, since you can't easily maneuver around the tree. You can either use pull the knife towards you carefully, using the same thumb pressure you used on the scion, or you can stand "behind" the stock and push the blade away from you.
- Start the cut about 1/3 of the way from the tip, or "toe"of the cut surface.
- Cut shallowly, and slowly, and very, very carefully. This is the most dangerous cut. Be aware of where the blade will go if you accidentally slice all the way through the wood, or if the wood suddenly splits.
- end the cut about 1/3 of the way from the "heel" of the cut.
Step 10: Caring for Your Grafts
First, LABEL YOUR GRAFTS!! I know you think you'll remember what varieties went where, but it's easy to forget. I use metal tags, which you can permanently mark with firm pressure from with a ball point pen. The letters will be engraved into the surface.
Then you just wait.
Not every graft will succeed, especially if you are a beginner. That's normal. your success rate will improve with practice.
Usually the graft will start growing "leafing out" or "breaking bud" in a few weeks. It's actually better if it leafs out late, since the scion can lose water through it's leaves. If the leaves emerge before the cambium has connected to the host tree, it will quickly dry up. Don't start worrying until about a month has gone by.
Occasionally a graft won't grow at all the first year, but will grow the
second year, but this is unusual. if it doesn't grow the second spring, prune it off.
Assuming it leafs out and the graft was successful, the scion may grow very rapidly. It's not uncommon for a graft to grow several feet long the first season.
Unwrapping the graft.
Leave the wrapping on for at least the first month. But you do need to remove the splicing tape eventually, because if the graft grows too much, the tape can squeeze the vascular tissue and choke the scion like a tourniquet. You should remove the rubber splicing tape in mid-late summer, and re-wrap the graft area in parafilm to keep it moist.
Don't let it fruit the first year.
rarely, a scion will produce fruit it's first year. if this happens, cut off the fruit. the graft union is not strong enough to support the weight. Many grafters wait two or three years before allowing it to bear fruit. Remember it's just a thing layer of growth holding it on the first year or two.
Removing the "dummy" scion
The dummy scion is the second scion in a larger cleft graft. It's the one that fills in the other end of the split. let it grow the first year, but you need to prune this off the next spring. two branches growing parallel to each other are going to cause problems later. as they grow larger, they will get a layer of bark trapped between them. this will limit the growth of the branches and weaken the graft junction.