Pruning That Apple Tree

Philip H. Norris
Blue Hill Tree Warden
Blue Hill, Maine 04614
*Presents*

Pruning That Apple Tree

Left to its own devices in nature, an apple tree will form into a multi-stemmed thicket, an unorganized, unlovely tangle.  From the tree’s point of view this is just fine.  It doesn’t care if it produces thousands of tiny apples instead of hundreds of large ones. It doesn’t care if the fruit gets shaded and doesn’t color up. The only thing the tree cares about is its biological imperative, its singular goal in life, to produce viable seeds.We, on the other hand, aren’t so interested in the seeds.  We have other goals for our apple trees.  We want fruit and we want beautiful looking trees as part of our landscape.  So prune we must.  How and when?

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First of all, the tree should be approachable.  If the lower branches are dragging on the ground and form a fence around the tree then they should be cut off or thinned.  What good is an apple tree if you can’t even get close to  it?  There should be an established route up into the tree for picking and pruning and for children and other tree climbers.  Secondly, all dead wood should be removed.  Then its time to step back and take a good look at the tree and think about balance.  Is the tree leaning?  Could the center of gravity be brought back over the trunk by pruning out a few limbs?  This is a crucially important step for young trees.  Keep the tree upright by pruning.

Apple trees are generally trained to a central leader when they are young.  Then when they are 8 or 10 feet tall the leader is allowed to whorl and the tree is encouraged to grow horizontally rather than vertically, broad rather than tall.  If you have an older apple tree these decisions have already been made for you and, for better or worse, the framework of the tree has already been established.  Regardless of how old the tree is there are some rules of thumb for pruning.  Prune out any new growth that is either vertical or heading back in towards the middle of the tree.  Direct all new growth out horizontally.  Let the lowest branches extend out the furthest, with each succeeding layer of branches stepped in so that they aren’t shading the lower branches.  Prune out any crisscrossing branches.  Make sure all branches have space around them, that they are not competing for sun and air with their neighbors.  The effect you want is a tree which is mostly clear in the middle with an even density of foliage towards the outside perimeter.  The old adage goes that an apple tree is well pruned when a bird can fly through it.  A healthy mature tree can be pruned quite heavily with no ill effects although you should attempt to remove no more than a third of the foliage in any given year.

No discussion of pruning would be complete without mentioning the importance of leaving the branch collar intact when removing a branch. The branch collar is the slight flare where a branch meets the trunk. Make your cut, not flush, but slightly outboard of the trunk and the wound can heal completely over in one season. Painting the wound with tree paint is an archaic practice that is no longer recommended.

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When is the best time to prune?  Prune when the tree is still dormant but the most severe cold weather has passed.  Late February to early April is ideal.

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(Phil Norris taught me how to prune apple trees)
(Which subsequently sparked my apple passion)
(Many thanks to Phil)
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watercore: a natural additive for hard cider in the south

I remember my first encounter with the “serious physiological disorder” called watercore. I was at an heirloom apple event in New Zealand, staring at a table full of old British varieties trying to decide which one to buy and eat first. I settled on a little russeted apple called Pitmaston Pineapple and once in hand, I took a large bite out of it.  The inside, to my surprise, looked like this:
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Photo Credit to Adams Apples
The taste was very sweet. A different kind of sweet, though, and it took me a year to come back around to figuring it out. This variety of apple, along with many other varieties, is susceptible to a “disorder” called watercore.
To the dessert grower, this “disorder” is bad news. Most people don’t want to bite into an apple which appears to have a water-soaked flesh because we’ve been taught that anything other than the usual white-crisp-juicy is to be avoided. However! I’m here to tell a different story, potentially one for the watery underdogs. A hopeful cider apple story.
First, let me give you some background on watercore…
To the apple industry, watercore is considered a “nonparasitic disease,” where the apple appears to have a water-soaked flesh. This “disease” takes shape in all apple growing regions of the US and seemingly has a few variants:
  1. Caused by a lack of water or droughty conditions
  2. Caused by a combination of genetics, the fruit being mature or overly mature, and sunscald due to intense heat.  
  3. Low calcium in your soils (which could go back to genetics since there are some calcium hungry cultivars, like Albemarle Pippin, which is known for watercore)
Why is it considered a disease? The brunt of it comes down to long-term storage. Apple packing houses aren’t able to store the apples with severe watercore because the tissues will eventually start to break down, causing the flesh to turn brown (and thus marked as unsaleable).  Another reason why it’s a bit of a bother to the apple industry is detection. Aside from some relatively recent research on detection methods, watercore has remained undetectable by the apple industry without the use of a knife (or teeth) to cut into the apple.
Like with the other apple diseases affecting the US, those with watercore are deemed as waste and dumped.  In my affinity for looking at common diseases as heroes of value-added products rather than boons to the established industry, I’m excited about watercore. Here’s why:
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The area above that looks water-soaked is actually where the apple has flooded its air spaces with a solution of sorbitol,  a non-fermentable sugar alcohol which is not technically a sugar. According to Claude Jolicoeur’s Book, The New Cider Maker’s Handbook, sorbitol has a sweetening effect that amounts to about half the effect of white sugar. This means that when a cider or perry (cider made from pears) is fermented dry (the yeast eat almost all of the available sugar and convert it to alcohol), the presence of sorbitol would still have a sweetening effect on the dry cider (because it doesn’t ferment).
The idea of a completely dry cider with a nice, fruity, slightly sweet finish is very appetizing to me and happens to fall in line with my low-input management thoughts from fruit to bottle. Here’s my thought process (and some background story) on this one:
A long time ago, I was helping out in a cider house and they were sending a finished cider through a sterile (sulfited) filter to both strain the yeast from the bottle, but also to prevent any yeast that managed to slip through from reproducing.  I was asked to taste the water being sent through the filter to detect the sulfur taste and the very moment when that sulfur water hit my lips, I was struck with an immediate and very scary asthma attack. That day I learned that I’m in the 1% of Americans who are actually allergic to sulfites and ever since, I’ve been a canary in a coal mine with respects to unbound sulfites in alcohol and suffice it to say, I’m not a fan of the additive. It has ruined many a cider/beer/wine for me due to my lungs closing up.
But why the use of a filter soaked in sulfites in the first place? When a cider is fermented dry, there is little fear of the cider/bottle of cider becoming unstable because all of the sugar in the cider has been consumed and turned into alcohol.  If cider is bottled and has both alive yeast and sugar, the cider will continue to change in taste as the yeast convert the sugar to alcohol and more carbon dioxide is being created, which has been known to cause exploding bottles. In this situation, the sterile filter was being used because the cider was going to be backsweetened (the addition of sugar after fermentation) with apple concentrate to give the final product some sweetness (Americans love sweet). To recap: Backsweetening + yeast= off flavors and potential explosions. Backsweetening + filter + sulfites= a sweetened cider with less fear of re-fermentation.
What does this have to do with sorbitol and watercore? A higher presence of sorbitol in a cider means my cider can be fermented completely dry (free of sugar) while maintaining a minimal sweetness without fear of re-fermentation. Eliminating this fear of re-fermentation means that I can eliminate sulfites from the back end of my cidermaking process.
Watercore= Higher Sorbitol Content= Residual Sweetness in a Dry Cider With Less Chemical Inputs. ding. Ding. DING!
Ok, so let’s say that I’m sold on experimenting with this sorbitol/cider thing and I want to grow fruit in order to make this product. Being in the South, I have a lot of hope for achieving such a thing because the causal agents are: Intense heat, lots of sun (sunburn), low calcium, droughty conditions, and genetics.
In designing an orchard and keeping sorbitol production in mind, I would entertain the idea of going towards more of a dwarf set-up, perhaps even a trelli$ set-up on a southwestern facing slope. We’re talking steaming hot, dry, with the trelli$ed fruit being exposed to intense sun.  On top of that, the apple system would be on irrigation which would allow you to regulate the amount of water and when to apply it. I’d also layout the orchard in a way which would drain quickly (maybe even a keyline design ;-)). Next, I’d choose varieties which are prone to watercore and also those that tend to hang on the trees rather than drop (which is a good genetic trait for apples in the South, anyways). Apples heading towards being overripe are at risk of watercore, so those that hold on are perfect candidates.
If you wanted to experiment with trying to intensify sunlight into a non-trellised tree, I would still try and have super quick water drainage off your site and have a SW aspect, but you could also try some extreme things like spraying all the leaves off your tree in late summer. I’ve done this for reasons of reducing vigor by using a 501 biodynamic prep, which I sprayed in late summer and managed to burn a BUNCH of the leaves off the tree…on purpose. I think the trick with this is in having a very vigorous tree and also determining the point of no return for apple ripening (if such a thing exists). The spray I applied in mid-August slowed the ripening scheme, which doesn’t help my sorbitol thoughts. However! It makes sense to me that reducing the leaf load on the tree would certainly help the sun scald situation.
I’ve never heard of anyone trying to grow apples with watercore on purpose, but why not? In straying from dessert fruit growing, managing for a certain product like cider could give regions like the South a distinctive taste in their products. We often think about this in terms of varieties and landraces,  which are certainly a part of it. But let’s try and capture our environment and create a truly unique product which describes our place in every way.
*This essay has been in the works for far too long and I decided to push it through today. I’ll likely go back over it an link to things stored on my computer and correct spelling/grammar.*

 

 

HELP WANTED! Fruit exploring for Hopewell Nurseries

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I am soon to launch The Fruit Explorers (.com) webpage, which will exist to be a resource/hub for fruit exploring projects happening around the country. But for now, I am crowdsourcing help for a huge project to find the genetics from Hopewell Nurseries, a pre-Civil War nursery which sold thousands of fruit trees, grape vines and roses (many of which are extinct cultivars).

The ledger from this nursery has been discovered and dates from 1833 to 1860. This ledger contains the names of people who bought trees and often their addresses, which is an absolute gold mine for fruit preservationists/explorers because there may still be trees/vines standing on some of these properties. Many of the cultivars produced by this nursery are now thought to be extinct…so here’s our chance to try and find what’s left. But time’s a ticking! These trees will be well past maturity and the threat of development in this area is a daily pressure on the landscape. We need to create some awareness and get information ASAP in order to see if anything still exists.

We need the following for step 1:
-TELE-RESEARCH VOLUNTEERS. For those interested in volunteering, Eliza will hold a “google hangout” to explain how she uses the public domain (internet) to do fruit exploring research. A volunteer has already gone through the ledger and typed out 26 pages of names and we need to find what we can about these people. Where they lived, if they were members of horticultural societies, etc. You can do this from the comforts of your own home (or work). This is a massive undertaking that can only happen with the help of others. Once we get this information, we’ll all be able to start searching!

If you are interested, please leave a comment below! And check out the catalog for what Hopewell Nurseries once sold!
https://archive.org/details/catalogueoffruit1859hope

Ugly Fruit is Especially Nutritious

And this spin off from Jill Neimark’s NPR piece just happened, this time in Food&Wine!

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By James Oliver Cury Posted April 27, 2016

Bruised and scabbed apples have more antioxidants and sugars because they’ve fought off natural stressors.

Grocery shoppers don’t generally make a beeline to the scabbed and blemished apples. But maybe they should. New research shows that trauma to the fruit—stresses from fighting heat, bugs, and fungus—forces apples to produce antioxidants such as flavonoids, phenolic acids, anthocyanins and carotenoids. And these compounds have all kinds of nutritional value.

Click here to read moreContinue reading

Nature’s Secret: We May Have Totally Underestimated Scarred Fruit

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A spin-off article from yesterday’s NPR article on eating ugly fruit, this time on weather.com! I’m so psyched this is getting attention. It’s only the beginning!!

Let’s face it: ugly fruit gets a bad rap. It’s often left behind at grocery stores and sold at steep discounts at farmers markets. More often than not, it gets tossed on top of an ever-growing pile of wasted produce.

But it turns out, these ugly fruits are fine to eat – and they may even be more nutritious.

 

Read more: Here!

Beneath An Ugly Outside, Marred Fruit May Pack More Nutrition

 NPR wrote an article about #eatuglyapples AND IT ALL STARTED WITH THIS BLOG! 

Unsightly scars on the outside of fruit might reflect higher nutrition within.

Unsightly scars on the outside of fruit might reflect higher nutrition within.

Daniela White Images/Getty Images

When orchardist Eliza Greenman walks through a field of apple trees and gazes upon a pocked array of blemished and buckled fruits — scarred from fighting fungus, heat and pests — she feels a little thrill of joy. “I’m absolutely infatuated with the idea of stress in an orchard,” says Greenman, who custom grafts and grows pesticide-free hard cider apples in Hamilton, Va. These forlorn, scabbed apples, says Greenman, may actually be sweeter.

 

Read more, HERE.

Hugh Ermen: Own-Roots Experimenter

Growing Apple Trees on their Own Roots

By Hugh F. Ermen (article appears on OrangePippin)

Hugh Ermen was one of the UK’s most successful modern apple breeders. He has raised Scrumptious, Red Devil, Winter Gem, Limelight, Herefordshire Russet and many others. He a leading exponent of the technique of growing apple trees on their own roots – rather than the standard practice of using dwarfing rootstocks. This is a copy of his work based on the experience gained over 25 years propagating and fruiting own root fruit trees of many varieties. Many fruit growers with long experience will know that growing a tree as naturally as possible is the best way.

Own root trees behave exactly as you would expect. Differences occur in trees on rootstocks due to the various degrees of incompatibility between stock and scion, which means there will be greater differences with dwarfing rootstocks.

Cropping will vary according to variety whether on own roots or rootstocks. I have found cropping more regular on own root trees, again as one would expect. Fruit size and quality at least as good but normally better. It has sometimes been suggested that we need trials to establish whether own root trees are better than trees on rootstocks. Having given this much thought, I would suggest this would be a waste of time and money. A trial would be influenced by the person conducting the trial whether intentionally or not. Of course apple trees grow well on their own roots, are the natural forests of apples on rootstocks?

The vigour of own root trees must be considered if you have little space. Triploid varieties will need more space than diploid varieties but I have found if they get the space they perform very well.

There are many basic techniques from planting to pruning which can be used to help control vigour, with cropping being the best control. For the newcomer to own root trees, I suggest starting with spur types and heavy cropping diploids. For the experienced person with enough space, the triploid varieties will not present a problem and you can always graft a fertile pollinator in the tree for the leader!

For the fruit tree nurseryman, the own root fruit tree should make propagation cheaper and reduce the risk of virus disease spread.

FRUIT ENTHUSIASTS – TRY OWN ROOT TREES!

Every variety of apple started life as a seed and in the past seedlings were selected growing on their own roots. Today the practice of apple breeders is to work the seedlings on to a dwarfing rootstock to bring them into cropping quickly. It is now well known, but often ignored, that degrees of incompatibility can exist between varieties and rootstocks, especially with the dwarfing rootstocks. It is probable that some potentially good varieties have been discarded in the past because partial incompatibility caused the seedling to give a poor performance on dwarfing rootstocks. A better but not necessarily quicker alternative would be to keep seedlings for assessment growing on their own root system. There are many well known ways which could be used to bring such seedlings into crop quicker.

As a general rule, the first seedlings to fruit from a batch of seeds are often flowering crabs, around year three to four. The next to flower are more likely to be good cropping diploid varieties. Seedlings that take six years or more to flower and fruit are usually moderate cropping diploid varieties. Triploid varieties are usually the last to flower and fruit which can take ten years.

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Comparison of Cox’s Orange Pippin trees growing on M( dwarf rootstocks (left) and own-roots (right). The own-root trees have the same vigor as Cox on MM106 semi-dwarfing rootstock.

Experience gained over the last thirty years has shown that assessing seedlings grown on their own roots gives more information to the apple breeder. It is very useful to know the natural vigour of a seedling, its’ growth pattern, cropping habit, fruit quality and natural resistance to pests and diseases without any rootstock influence.

 

The realisation that a rootstock influence on a variety is greater than at first thought, gives grounds to have a collection of the main apple varieties propagated on their own roots. This would reveal the natural characteristics of each variety and although more land would be needed than a collection on dwarfing rootstocks, this would be offset by double the lifespan of the own trees roots.

Growing apples on their own roots is not new. A reference can be found in the Transactions of the Horticultural Society of London where Mr Arthur R Biggs F.H.S., read a paper in February 1807. Only a few apple varieties could be propagated by cuttings, until research showed the way with use of heated propagating bins and micro propagation. Further progress with own root apple trees has been very slow, due to the major cut backs in Research and Development.

However, there is now enough experience with own root apples to make further development work worthwhile and the breeding of compact varieties to exploit the benefits and overcome the drawbacks.

Advantages of Own Root Trees

  1. Better tree health- Each variety differs in its precise nutritional requirements which can easily be achieved naturally, by growing a variety on its own roots. There is a difference between the uptake of nutrients by a rootstock and the exact requirements of the scion variety worked on it. This mismatch can lead to a reduction in the health of the scion variety and fruit quality.
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Red Devil on own roots, cropping heavily

  1. Better fruit set.
  2. When a variety that comes into growth early is worked on a late starting rootstock and flowers before the rootstock becomes active, poor fruit set will result.
  3. Better fruit quality and storage life
  4. Better resistance to pests and diseases
  5. Excellent for pot culture

Disadvantages of Own Root Trees

  1. No rootstock vigour control
  2. Insufficient development work at present on large scale propagation of own root trees.

A Vigour Guide To Own Root Trees

  1. Dwarfing – semi dwarfing (M9 – M26) Diploid compact spur type varieties and clones (e.g. Starkspur Golden Delicious)
  2. Medium Vigour- The majority of diploid varieties (e.g. Cox’s Orange Pippin)
  3. Vigorous- The majority of triploid varieties (e.g. Bramley Seedling)

Tree Management Techniques

There is plenty of scope for innovation, especially for the amateur. The following drawings of possible tree shapes and planting systems will stimulate further innovation.

Tree forms

Centre Leader

Diagram
45 degree Plant

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Stem Loop

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The Umbrella

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Zig Zag Stem

Diagram
Tripods
No tree stakes required. Tripod trees withstood the hurricane in Kent without damage. Base of the triangle is 1m x 1m x 1m.
Diagram

Tent
No tree stakes required. Tree vigour can be controlled by reducing or increasing the angle of the trees. Base of the square is 1m x 1m x 1m x 1m.

Diagram

The Curtain
Posts and wires needed for support. This system requires some experience of spur pruning

Diagram

The Combo
Central tree is a Wijcik type pollinator. An alternative is to graft a pollinator variety directly on to the tree.

Diagram

Cox own-root tripod detail3 x Cox’s Orange Pippin own-root trees grown as a tripods to control vigour (1m between each tree) – 1998

Techniques to encourage early cropping

  •  Plant well feathered maidens or possibly 2yr old trees
  •  Plant at an angle of 45 degrees
  •  Tying down branches near horizontal
  •  Summer pruning
  •  Minimum winter pruning
  •  Bark ringing (not in year of planting)
  •  Bending over and tying down leading shoot in late June
  •  Root pruning
  •  Grassing down orchard
  •  Careful use of fertilisers, especially Nitrogen

In general, flowering and harvesting times will be similar to trees grown on MM106 rootstock. Fruit shape will be typical for the variety (MM106 produces a slightly more conical Cox fruit).

The culture of own root trees

  •  The Site The same as for trees worked on a rootstock
  •  The Soil

Own root trees do not require the rich deep soils which are desirable for trees on dwarfing rootstocks. Cox’s Orange Pippin is sensitive to soil pH and will not tolerate a pH below 6.5 and grows better in neutral soil.

The Prejudice Against Own Root Trees

Many Growers have experienced scion rooting in orchards of trees grown on the dwarfing rootstocks M9 and M27. These trees become vigorous as a result of scion rooting and receive hard pruning in winter to keep them confined to their allotted space. This practice causes the trees to grow more vigorously and become unfruitful. The conclusion reached is that trees on their own toots are vigorous and unfruitful, which they can be in these circumstances.

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3 mature Cox’s Orange Pippin own-root trees grown as a tripod

Some research workers, but not all, feel that own root trees are a retrograde step, after all the research that has gone into rootstocks. On the other hand, research work has made own root tree propagation a practical proposition and both England and Europe trial orchards were planted, but cutbacks in research terminated this work. Extended private observations of own root trees has indicated that further development work is worthwhile, especially with organic growing in mind.

Views have been expressed that uniformity of trees on rootstocks is much better. The author has not found this to be correct. Uniform planting material produces uniform trees, whether on rootstocks or own roots.

Years ago, some plum orchards were grown on their own roots and were re-propagated from suckers. This lead to a steady decline due to virus and other diseases, which were little understood by management at the time. With all fruit propagation it is essential to use virus free material whenever possible.

Reliable information from home and abroad has stated that Cambridge Gage used to grow and crop better on its own roots than worked on a plum rootstock. This is now being checked with trees growing on their own roots. Trees of Victoria are also being observed on their own roots.

The Propagation Of Own Root Trees

  • No large scale production of own root trees exists at the present time.

Micro-propagation

This should be the fastest method for large scale production. It has to be carried out with skill and care, to avoid the production of ‘OFF’ types. Trees raised in this way experimentally, have initially been more vigorous and slower to crop than trees from hardwood cuttings. No doubt with more development work these slight drawbacks can be overcome.

Hardwood Cuttings

Variable results have been obtained with hardwood cuttings placed in heated propagating bins. The optimum base temperature has to be worked out together with the air temperature of each variety. For example, Bramley Seedling roots well if cuttings are taken at leaf fall and placed in a propagating bin with base heat of 25° C and in an air temperature of 20° C. Many other varieties rooted with an air temperature around 5° C. There was also marked seasonal variation in rooting. The use of a rooting hormone (IBA) was essential with most varieties. The method is only used for easy rooting subjects commercially, such as rootstocks. New simpler techniques are being evaluated by F.P. Matthews of Tenbury Wells.

Nurse Root Cuttings

This method has proved reliable using M27 nurse roots. Many if not all, varieties can be rooted by this method with or without rooting hormone. Giving base heat in a propagating bin gives speedier rooting, or placing unheated bins under plastic or glass. Placing the cutting bins outdoors can also be successful. This method is used initially to get a variety on its own roots.

Root Cuttings

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The Katy apple tree on it’s own roots, kept to the same size as M9 trees by allowing very heavy cropping.

Roots from preferably young trees, about pencil thickness, can produce a whip about 50cm tall in one growing season in an outdoor bin. Feathered maidens have been produced from roots if the bins are placed under polyethylene or glass. Outdoor benefits from insulation against excessive cold or hot ambient temperatures. Bins are best raised off the ground and placed in good light conditions. It is an ideal method for small scale production.

Propagating Pears, Peaches, Plums and Cherries

The same methods described for apples can be used for pears and plums. The author has limited experience with peaches and cherries. Peregrine peach raised by semi-hardwood cuttings under mist cropped very well indeed. A nurse rooted (using Colt) Stella cherry grew and fruited well. Peach root cuttings from Peregrine tried on a very small scale have not been successful. Roots from Colt cherry rootstocks grow very well.

Future Potential For Own Root Trees

The full potential for own root fruit trees will only be revealed when we have gained sufficient experience of the best methods of propagation and culture. Gaining this experience will be exciting for the dedicated fruit enthusiasts be they amateur or professional. The biggest difference in fruit quality and flavour between own root trees and rootstock trees will be found between own root trees and trees on dwarfing rootstocks.

Trees growing on their own roots may not crop more heavily or have better fruit size than trees on M9 although better cropping and fruit size has been apparent with some varieties. What can be virtually guaranteed with the experience gained so far, is more regular cropping and better quality fruits which have a better storage life. Fruit flavour could well be more intense and with generally more seeds per fruit, better fruit shape. In the end it will be the grower who by his skill, can manage own root trees and obtain the full potential.

Pruning Guide for Own Root Apple Trees

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Cox’s Orange Pippin own-roots trees grown as tripods to control vigor

The vigor of an own root apple tree depends on the variety or clone, not on a selected rootstock. The best way to control the vigor of an apple tree, whether on its own roots or a rootstock is by cropping.

The basic vigor range of rootstocks is:

  1. Dwarf – semi dwarf Rootstocks M27, M9 and M26
  2. Medium vigor Rootstocks MM106, M7 and MM111
  3. Vigorous – very vigorous Rootstock M2, M16 and M25

The vigor of named fruiting varieties can also be grouped into three categories:

The vigor of named fruiting varieties can also be grouped into three:

1. Dwarf – semi dwarf

  • All Wijcik (Ballerina) varieties
  • Starkspur Golden Delicious
  • Granny Smith Spur
  • Lord Derby Spur (culinary)
  • Sunburn
  • Cox Spur Type
  • Discovery Spur Type

2a. Medium vigor (Dessert) mainly diploid varieties

  • George Cave
  • Discovery
  • James Grieve
  • Worcester Pearmain
  • Lord Lambourne
  • St. Edmund’s Pippin (russet)
  • Cox’s Orange Pippin
  • Sunset
  • Golden Delicious
  • Winston
  • Pixie
  • Sturmer Pippin

2b. Medium vigor (Culinary) mainly diploid varieties

  • Early Victoria
  • Grenadier
  • Rev. W. Wilks
  • Arthur Turner
  • Golden Noble
  • Bountiful
  • Lane’s Prince Albert
  • Annie Elizabeth
  • Edward VII

Vigorous – very vigorous -mainly triploid varieties

  • Blenheim Orange
  • Bramley Seedling
  • Crispin
  • Jonagold
  • Jupiter
  • Newton Wonder
  • Orleans Reinette
  • Ribston Pippin
  • Suntan

Pruning apple trees

This is carried out in two stages.

1.At planting time to train the tree to grow into the desired shape.

  • ◦ Pyramid and Spindle Bush
  • ◦ Bush 3′ leg
  • ◦ Half standard 4 1/2′ leg
  • ◦ Standard 6′ leg
  • ◦ Centre Leader
  • ◦ Cordon
  • ◦ Espalier
  • ◦ Fan
  • ◦ Tripod (three trees)
  • ◦ Step over

3. Growing tree

  • ◦ To let light and air into mature trees to encourage flower buds,
  • strong mature flowers and good quality fruit.
  • ◦ To cut out damaged or diseased wood.
  • ◦ To regular cropping by removing excess fruit buds especially by
  • thinning complex spurs.
  • ◦ To renew branches.
  • ◦ To retain a balanced (stable) tree.
  • ◦ To allow access for picking fruit.
  • ◦ To maintain tree in space provided.

FAILURE to prune mature trees will lead to:

  •  Tangled and overcrowded growth.
  •  Excessive cropping which increases the risk of biennial bearing.
  •  Excessive shading causing small, inferior quality fruit.
  •  Difficult to pick fruit.
  •  Increased pests and disease.
  •  Harder to get good spray cover.
  •  More likelihood of unbalanced growth leading to a greater risk of tree
  • instability, especially when carrying a heavy crop.

Growth characteristics of apple trees

Two kinds of buds can be found on apple shoots/branches. On one year old shoots there will be small wood buds. In the second year some wood buds will fatten up and become fruit buds. The terminal bud at the end of the shoot will normally continue the shoot extension although in a few varieties (tip bearers such as Worcester Pearmain) the terminal bud will often form into a fruit bud, and fruit in the 2nd year. In the third year flowers will emerge from the fruit buds and if pollinated successfully, the flowers will grow into apples.

The fruit buds on two year old wood are in reality very short shoots calledspurs. Some varieties called spur types grow further spurs as the apples are growing, instead of shoots. Normally each spur will terminate in a fruit bud. After a few years the spurs become numerous and the quality and size of fruits formed on them deteriorates due to competition. It is then necessary to thin the spurs in the winter, so that competition is reduced. Apple varieties forming spurs readily are the easiest to manage on their own roots, as much as of the natural tree vigor foes into the production of apples. All the other varieties need to be pruned to encourage a good balance between growing and fruiting.

Time of pruning and effect

Winter

Pruning in winter reduces the aerial parts of the tree but not the roots. The effect will be to increase the vigor of shoots and branches and discourage formation of fruit buds. Winter pruning is ideal for trees that have too many fruit buds and little extension growth. Pruning young trees where growth is needed and directed in to forming the tree, rather than fruit production, is carried out in winter.

When the trees are leafless in the dormant winter season, damaged, diseased or congested growth can easily be seen. If the tree is very vigoros, winter pruning is less desirable. In this case it is best to leave pruning until growth in the spring starts, or prune directly after picking and before leaf fall.

Summer pruning

At this time of year, pruning reduces the number of leaves which manufacture food materials. Summer pruning therefore reduces the vigor of the tree and improves the cropping potential. Summer is an ideal time to remove strong vertical shoots which are generally unfruitful and shoots growing underneath branches which get heavily shaded.

Pruning – apical dominance

The highest bud on a shoot, pruned or unpruned will be dominant and will grow out stronger than any other bud. The strongest growth will be at the top of a branch or tree. When growing a centre leader tree (a tree with a central trunk up to the leading shoot) you control growth using the leading shoot of the stem. Cutting back the leader will increase growth in the lower branches. Leaving the leading shoot unpruned will reduce vigor in the lower branches. The harder the tree leader is pruned (ideally down to a well placed weak shoot) the greater the vigor increases in the lower branches.

Pruning methods

Pruning is best demonstrated in the orchard. Failing that, watch the response of the tree to pruning and react accordingly.

Regulated pruning

This is exactly what it says. Pruning to regulate the tree growth and cropping. Basically a tree is pruned to get balanced growth and branches to carry fruit in good light and air. Vertical growing vigoros shoots are usually unfruitful and shoots growing downwards underneath a branch get heavily shaded, both types should be removed. Shoots growing out from the sides of branches are ideal for carrying fruit. When these side shoots have grown too long they are best cut back to the main branch with a sloping cut, leaving more stub underneath to encourage a renewal shoot to grow from the stub at a nice wide angle.

The basic bush tree and centre leader tree should have about four main branches, arranged around the tree for good stability. The height of these branches from the ground will depend on the type of tree being grown. Bush trees have branches around 3′ from the ground, half standards 4 1/2′ and standard trees 6′ from the ground. Centre leader trees normally have their main branches at waist height for easy harvesting of the fruits. Branches above these are renewed before they get too big, by cutting them back to the trunk with a sloping cut to avoid too much shading of the main branches.

Spur pruning

This method of pruning is mainly used for cordons, espaliers and other more formal shaped trees. The object is to create fruiting spurs close to the stem and main branches. Some varieties form spurs very easily (Starkspur Golden Delicious) and are known as spur types whilst others range from easy to difficult.

The difficult varieties are usually tip bearers (e.g. Worcester Pearmain) and vigoros triploid varieties (e.g. Bramley Seedling). Spur pruning is mainly carried out in the summer and involves cutting back shoots growing directly from the stem or main branches to encourage fruit buds to form near the stem or branch. There are many ideas about how best to achieve fruiting spurs close to a stem or branch. The vigor of the tree can be used as a guide.

Weak growing trees

Prune young shoots when they reach 9″ and cut back to an underneath bud around 6″.

Moderate vigor trees

Prune young shoots when they have reached 12″ back to an upward growing bud around 9″. The shoot will almost certainly grow out from that top bid and can later be pruned back to the underneath bud behind the top bud which has grown out at a better angle.

Vigorous trees

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Orange Pippin Own-Root Trees, 1987

Prune young shoots that have reached 18″ back to top bud around 12″ then continue as for medium vigor trees. This can only be a rough guide and timing will differ due to weather, culture etc. Watch the tree’s response to pruning and adjust accordingly. Ifthe tree has not responded with fruit buds near stem or main branch it is best to cut the shoot back to the stem or branch with a sloping cut to encourage a further shoot to grow out at a wide angle and start again.

Grafting shoots into strategic positions

If all else fails, there is a graft that can place a shoot in a branch or stem, provided the stem or branch is reasonably thick. This involves collecting dormant one year old shoots in early February and placing them upright in a pot of sand to a depth of 4-6″ which is then placed in a cool shady part of the garden. Alternatively, shoots can be placed in a polythene bag (not airtight) and stored in the vegetable compartment of a refrigerator. In April when the sap rises and the bark will lift, the stored shoots can be used for slit grafts in the bark. This enables shoots to be placed in ideal positions on stem or branch. Length of grafts depends on the vigor of the tree. 4″grafts for weak growing trees, 6″ for moderate vigor trees and 8-9″ for vigorous trees. These grafted shoots normally form fruit buds easily.

Pruning should not be regarded as an isolated operation but as part of the tree culture and taken together with soil management and cropping. For more detailed information about pruning, the R.H.S. Wisley Handbook on Pruning Hardy Fruits by Jack Woodward can be highly recommended.

H.F.Ermen. A.H.R.H.S., N.D.H.

Mr Ermen died in 2009. In March 2010 the UK Royal Horticultural Society recognised Scrumptious, one of the most popular varieties raised by him, with the Award of Garden Merit – the first such award given to an apple variety for more than 10 years.

On their own roots

A long time ago, orchard and nursery people often grafted scions from known cultivars onto dug-up root pieces from apple trees. This was one of the ways in which orchardists and nurserypeople were able to propagate specific varieties rather than getting something completely random from seed. The other way was to graft onto existing trees (called top-working, or top-grafting) or onto rootstock produced by planting seeds.

 

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Root grafting (on purpose) has largely disappeared as a horticultural practice due to the rise of clonal rootstocks. We are now able to decide what size tree we want and how soon we’d like the tree to bear apples, which has been the primary cause for eliminating old “standard” sized trees from the landscape.  In fact, you wouldn’t believe how many old orchards I visit where the owners have been told by the extension service to cut down the old orchard and plant high density apples…

It’s true that high density apple systems have proven themselves to make more money than trees able to stand up by themselves (in a high-input dessert fruit market), but I’m not totally sold on that model when it comes to growing process fruit for cider, pies, etc. I’ve run the numbers (which I’ll share soon) and you’d have to plant many, many acres of apples to make it work out financially (if you were to sell wholesale and not turn them into your own value-added products). After it’s all said and done, you’ve got an orchard that can live for 25 years on a spacing that makes it hard to “stack functions,” or grow other crops/animals within your system to have a diversified income (which is necessary for me)

*Disclaimer* I have heard from a smart orchardist outside of Pittsburg who is growing black raspberries on the same trellissing as his high density apples with wild success.

 

Eliza fameuse tree

Back to root grafts:

  • Yes, these trees are often times very large compared with apple trees grown on clonal rootstocks.
  • Yes, they are going to take 10-10+ years to bear fruit.
  • Yes you can only fit 55 trees per acre…

But…

  • I’ve seen a lot of old apple trees in my lifetime, like the one pictured above which is over 200 years old! That tree was root grafted and, as a result, on it’s own roots.
  • The Fruit Explorers, a group of which I’m a founding member (along with Pete Halupka of Harvest Roots Farm and Ferment), traveled around the South last year looking for all sorts of apple trees. By far, the healthiest trees we found were those on standard rootstock or growing on their own roots. We were in the hot, humid, zone 7a-8a South which is known for all sorts of rots, fireblight strikes, fungal infections…you name it. And the trees that looked the best were the big ones. All of this observation caused me to believe that we probably have the best chances of growing low-input trees if they are on big roots.
  • I can grow other crops in the rows between the trees. I can graze animals. I can have a diversified income stream while waiting for the orchard to come into bearing and for the canopies to narrow the rows.
  • The trees will be of uniform size if you are root grafting the same cultivars within the row
  • Who’s to say these trees won’t each drop 100 bushels of apples a piece?

Basically, all of this is to say: I think that root grafting isn’t such a bad idea for an orchard if you have the space and the time.  I’m crossing my fingers that I’ll have the space in the next couple years, so the remainder of this blog post is about my thoughts and actual practices of root grafting…

This year, I ordered 1000 southern crabapple trees from the Maryland State Nursery (Malus angustifolia). I decided on M. angustifolia because I’m in the South and these crabapples are better adapted to this hot and humid climate. Also, I had already decided that I wanted standard sized trees, so why not use them as a rootstock?

Well, after I ordered them I did some digging and realized that M. angustifolia, which on average is not that large of a mature tree (maybe 20 feet), would probably not be able to handle the vigor of the heirlooms and cider varieties I wanted to graft. Across the boards, from writings I found in the 1800s to anecdotal quips from friends and thoughts from mentors, it seems like the majority of these seedlings would only be able to handle the graft for a few years and then the top would eventually outgrow the bottom, resulting in death. The success stories I read involved topworking mature, already-in-the-ground-and producing-crabapple trees OR grafting onto crabapple stock from Russia. Russian crab stock is more vigorous and able to handle the older varieties and I’ve seen evidence of this in very old orchards in Maine, where the cultivar died out and the crab stock bolted upward.

Compared to the Siberian crabapple stock we ordered last year (Malus baccata), this year’s rootstock was tiny and we were left trying to figure out how we were going to graft it because on average, our scion is larger in diameter than above the root collar. That’s when I settled on the idea of root grafting.

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This is a larger example of a the M. angustifolia crabapple we received from Maryland.

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I use a foot powered saddle grafter much of the time to save my hands because I battle carpel tunnel due to repetitive orchard/nursery movements combined with being on the computer too much of the time.

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This is what we’ve done to many, many crabapple trees. We took the root, made a grafting cut (some whip and tongue, many saddle, some omega and some cleft). Roots are often difficult for me to graft because many of them aren’t straight, but squiggly. This is where the saddle grafter came in handy, or we employed the cleft graft.

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We left the scions larger when grafted. Usually, you only need a bud or two for grafting but I decided to leave 5-6 buds for reasons I’ll tell you about later in this post.

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Pictured above is the final product. We grafted the scion to the root, wrapped it with a rubber band to make sure the union was nice and tight, and then wrapped the graft union/rubber band in parafilm (wax tape) from top to bottom. Some of you might be thinking: A rubber band PLUS parafilm! That’s overkill! And it is, to an extent (though it is pretty much a guaranteed take if you are able to make your vascular cambiums line up). But here’s why we did it…

By itself, horticultural rubber bands will degrade in the sun and fall off the tree within a certain time period so you don’t have to worry about it girdling the tree. By itself, parafilm will also degrade/expand/drop off a tree later in the season without it girdling the tree. TOGETHER, however, your tree is doomed for girdling unless you manually get out there in the summer and cut it off in time. I learned this the hard way, folks.

Why are we using this rubber band/parafilm method for grafting a root when I won’t be able to cut it off due to it being buried in the soil? Well- the answer is this: I want the girdling. Before I put this all together for you, I need to go on a brief tangent (which connects, I promise).

Last summer, we visited with Jason Bowman of Horne Creek Historical Farm (one of the sites that has Lee Calhoun‘s entire collection) and he was kind enough to take us through the orchard. Every year, I notice something different about trees and during this particular visit, I noticed how tree form differs from cultivar to cultivar. This is nothing new, really, because I’ve pruned many different cultivars of apples and they are all different. But this time, my knowledge of what trees had better disease resistances combined/confirmed with Jason’s were overlayed with tree form. I started to notice how apple varieties like the Dula Beauty naturally had wide crotch angles, creating better natural airflow and therefore, less fungal problems because humidity wasn’t being trapped within the tree as readily as some other varieties.

Keeping this in mind, I’ve been wanting to return my most disease resistant cultivars with excellent tree form (wide crotch angles) to growing on their own roots because I think they will require less pruning down the road (which is one of the big arguments for going to smaller trees…less and faster pruning). I want to see what size these trees will be without interference of rootstock, how many bushels of apples these trees will bear, and I want to taste an apple on it’s own roots as compared to another rootstock. That’s why we’re grafting in a way which will eventually have the root girdled from the scion (by using the rubber band/parafilm method). Alone, it’s fairly difficult for an apple cutting (scion) to produce roots on it’s own, so that’s why we’re grafting it to the crab roots. I want this crab stock to be a nurse to the scion, keeping the scion alive and fed while it starts to produce it’s own roots, and then to die off!

We left the scions long on these roots (5-6 buds rather than 2-3) to give room above the graft union to plant the scion. We’re going to try out two methods for this:

1.) We’re going to plant the whole thing and leave 2-3 buds sticking out of the ground. There will be irrigation.

2.) We’re going to plant the root and the graft union, and then cover the soil with several inches of sawdust which will be under irrigation. The area where damp sawdust contacts the scion should encourage root growth into that space.

When the time comes for digging these trees up and transplanting them, in a year or two, we may cut off the crab root if it’s still attached and alive. We’ll see! Updates to follow whenever we dig these things up (starting in the winter of 2016/2017).

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