Rootstocks: Do they impact flavor?

Earlier this year, as I was doing some research on the effects of grafting apple varieties to Malus angustifolia (southern crabapple), I kept running across interesting accounts of noticeable changes to the apple varieties when grafted to crabapples. One of these changes is in flavor, which is what I’m writing about today.

This is the original snippet that sparked my interest. Why? Because this dude back in the 1800s is telling me that when he took the Bethlehemite apple, a dessert/culinary apple from Ohio, and grafted it to a crabapple rootstock, he got something different from the original variety. The grafted Bethlehemite apple had developed some astringency. Astringency is the key word here.

OMG, DID THIS GUY TURN A DESSERT APPLE INTO A CIDER APPLE BY GRAFTING IT ONTO A CRAB ROOTSTOCK?

This thought has rumbled around in my head for the better part of this year and whenever I had a moment to sit at the computer and not read my emails, I researched this topic a bit more. First, I went back in history (via google books) to find more testimonials of these findings. Here are a few:

1867:

1871:

1873:

1889:

 

I could go on, but there are many, many testimonials in favor of rootstock having a flavorful impact on the grafted variety. There were some naysayers, who basically just said “this can’t be so” and changed the subject. But all in all, my historical research has been in favor of a rootstock’s ability to change flavor in apple varieties.

Eager to pursue this topic, I started looking up scientific papers on the subject and started with this, Cornell’s research on nutrient uptake by different rootstocks.  The thoughts and questions of the horticulturalists back in the 1800s seem to still align with the questions of today, as seen in this conclusion:

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“The ability to match the nutritional requirements of a scion cultivar to a specially tuned rootstock…” COULD, in my opinion, create a cider apple out of a friggin’ dessert fruit.

Positive, I kept up the research and found considerable evidence in citrus fruit that rootstocks can change the flavor of the fruit. Here. Here. And Here.

This study, which looked at an apple rootstock’s impact on triterpene (cancer and immune disease prevention chemical compounds) found this:

“The largest differences in triterpene content were found between rootstocks. The results showed that both at harvest time, and after cold storage except the first harvest time samples, the apples from rootstock MM106 had significantly higher triterpene content compared with those from M9; … Selecting suitable rootstock might increase the triterpene content in apple peel in practice production.”

And this study on different rootstock’s impact on peaches showed that the variety ‘Suncrest’ on Julior (rootstock) and GF677 (rootstock), followed by Ishtara (rootstock), produced fruit with the greatest antioxidant activities and total phenolic contents. The ‘Suncrest’ on Citation (rootstock) and, especially, Barrier1 (rootstock) had reduced nutritional values of the fruit.

WHAT DOES THIS ALL MEAN? 

Right now, everyone I know who is planting a cider orchard is planting on known rootstocks like the MM series or the Geneva $eries. With these rootstocks, we know what size of tree we’ll get and we generally know when it will start cropping apples. This is valuable information because we want order and sense in our orchards. We also know the disease tolerances of each rootstock, which have been known to convey some resistance to the apple scion, and that’s all well and good. There are many knowns of these rootstocks because they’ve been extensively studied…for dessert fruit. But what about cider fruit? How many rootstocks have been thrown out in university trials for imparting astringency to an apple? Probably a lot. But what if this is what we’re after?!

If someone came to my farm peddling their wares and told me that they could take my dessert apple and turn it into a cider apple with one of their amazing magical rootstocks, I would buy it. I’m sure it would be a hit. This is why we have started in on the private research of grafting apple varieties to different rootstocks for the purpose of flavor/nutrient evaluation (as well as growth influences, which is another blog entry).

Currently, my partner and I have Malus angustifolia (southern crab), Malus baccata (Siberian crab), own-root, M7 and M111 trees grafted in our nursery to the same variety. These will soon get planted out at the farm in an area set up for evaluation. This, I believe, is another untouched frontier whose findings could be incredible for the future of growing superfruits, having value-added rootstocks, and growing with lower inputs.

So far, the science and the observations are there. There’s much more to learn, but why not start in on the fun?

 

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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:
watercored_cox
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:
430-120176image20water20core20120correct
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.*

 

 

Ugly Fruit is Especially Nutritious

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

201410-hd-apples-to-know-esopus-spitzenberg

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

marred-apples-market

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.
he-red-devil

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

Diagram
Stem Loop

Diagram
The Umbrella

Diagram
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

he-katy

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

he-cox-tripods

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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There’s More to Eating Ugly

Today I attended Future Harvest-CASA‘s annual conference, which focuses on sustainable agriculture in the Chesapeake Bay watershed. I grew up on the Chesapeake Bay and even in my short 32 years on this earth, I’ve been witness to it’s decline due to poor agricultural/homeowner practices and various versions of greed permitted on local,state and federal levels. A concept like saving the Chesapeake Bay is one that is overwhelming if you think about all of the moving parts, but if you think about what you do on a daily or weekly basis, and then add some Chesapeake Bay awareness and adjustment..you’re making a difference. If everyone does this, a small difference turns into a big difference and a new conscious culture is underway. Voila!

Back to the conference… I attended one session about eating ugly fruits and vegetables, where the founder of FruitCycle, Elizabeth Bennett, gave a candid talk about her eat ugly business model and how it was going. From her website, TheFruitCycle.com:

Fruitcycle is a social enterprise that makes delicious, healthy, locally sourced snacks. We focus on using produce that would otherwise go to waste and we provide jobs for women who have been formerly incarcerated, homeless, or are otherwise disadvantaged.

The idea of taking beaten, bruised, battered and unsaleable produce and turning it into a nutritious value added good is an important one which resurrects nutrition from a landfill fate. There’s a lot of talk around the importance of these actions and many people are starting companies to deal with this “waste.” I’m a full two-thumbs-up about all of this, but there’s a part of me that aches to shout: There’s a lot more to eating ugly than keeping foods out of the landfill!

First of all, let me point out that this ugly food movement is currently built on the waste stream of conventional agriculture. This form of agriculture is often short-sighted, input-driven and damages ecological/human health systems in ways we know and do not yet know. In the case of apples, the ones getting repurposed are also the ones whic were sprayed with pesticides and didn’t make the cut as a fancy grade A. I am not ok with this. Yes, we’re reducing the waste-stream; But are we changing anything about agriculture or the health of humans and the environment? Probably not.

This is what eating ugly means to me:

1.) Eating truly ugly fruits and vegetables can help to heal your watershed.

Ugly Apples

The apples pictured above are about as ugly as it gets. Aside from the puncture marks (I shook the tree and picked-up the apples rather than hand-picking from the tree), there are a multitude of ugly things going on with this apple that aren’t acceptable by the general public. In addition to a splotchy multi-colored complexion and a short and squat stature, there are two cosmetic blemishes present: sooty blotch (the dark blotches) and fly speck (the small black dots). Both of these cosmetic blemishes are caused from harmless fungi that doesn’t change the flavor, texture, or anything about the apple other than looks. In case you winced when thinking about an apple covered in harmless fungus, just remember: You, the reader, are also covered in lots of fungus

Unless you have an apple tree in your yard and/or happen to know where an abandoned orchard is somewhere, you likely don’t ever see apples like this. That’s because millions (yes, millions) of gallons of fungicide are sprayed on orchards across the United States every year just to make these apples look like this:

Granny Smith Apple

Rather than this: (both are Granny Smith apples)

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There are other inputs, too… pesticides which kill both beneficial and pest insects, herbicides to control the grassless strip under the trees, and synthetic fertilizers to get these crops producing, etc. Whether by a disruption of the ecological food chain or actual chemical contaminants, many of these inputs eventually wind their way to the decline of our tributaries and various bodies of water. All because we have been taught to eat perfection. 

What if we ate ugly because it meant that we approved of ecologically and humanely ethical growing practices? What if producing ugly was on purpose and not a waste product? In becoming more conscious of our eating acts, even if it’s just choosing to eat a low-spray apple, we are taking steps towards saving the Chesapeake Bay. We have that power.

2.) Eating ugly encourages diversity

green-light-collection-apples-for-sale-at-grocery-store-on-oxford-street-paddington-sydney-new-south-wales-australia

There are more than 7000 varieties of apples in the United States right now. They vary in size, shape, color, taste, texture, weight, keeping ability and culinary use; you name it, there’s an apple for that. These apples also grow in different locations, need different nutrients, and have different tolerances to insects and disease. Yet, all we know are the grocery store 8 and that’s because the extension service and the land grant universities don’t know anything other than these apple varieties and their offspring.

When encouraging someone to eat ugly apples, I’m encouraging them to eat an apple that looks like a potato; one that doesn’t have a uniform color scheme; one the size of a ping-pong ball; one that has lumps. These small, ugly, lumpy apples might be better adapted to your area than, say, the usual glistening orbs of perfection pictured above. And when a tree is able to get what it needs from a site rather than rely on inputs from humans, we’re creating an agriculture that is more naturally organic…and delicious…and ethical. I won’t ever push an apple on you that doesn’t taste amazing in cider, or a pie, or in molasses, or as a dried apple.

3.) Eating ugly can be more healthy for you

It has been scientifically proven that apples with cosmetic disease can be considered super fruit due to the nutrients being pumped into the apple from the tree when under “attack.”

4.) Eating ugly allows one to access healthy, ethically minded food more affordably

In minimizing the inputs, the grower is paying less for producing a crop. This carries over to the consumer.  You want organic? You want probiotic? Eat ugly. But not just any ugly; ask how the produce was grown. Then give feedback. Lots and lots of feedback.

 

Cider And Heirloom Apple Vigor: An Hypothesis

Recently, I was on the phone with a mentor and we were discussing hedgerows (my new pet project, aside from brewing all sorts of alcohol). With some of the species I mentioned, I was told that livestock would eat them down to nothing and render the hedgerow useless. After having a few tree species rejected, I frustratingly asked: “What if I planted my hedgerows with invasives like multi-flora rose, then?!”

Without any hesitation, my mentor said: “Invasives like multi-flora rose are very delicious to many animals, like my goats.  You might be suggesting invasive plants for your hedgerow because they are vigorous and seem to outcompete everything else, but try to think about vigor from another perspective. If plants with high vigor are also the most sought after by animals, don’t you think that vigor might be an evolutionary trait to survive browse?”

This is the first time I’ve heard this perspective on invasives and I’ve really enjoyed thinking about it. After some minimal research, I found out that the subject is still debated today by ecologists as the “plant vigor hypothesis.” Generally speaking, vigorous plants have higher nutrient densities than non-vigorous plants, so herbivores are more prone to eat them. However! If the very vigorous cultivars are able to put on a bunch of girth, many herbivores aren’t able to eat the whole thing because of their jaw size.

This, of course, has got me thinking about apples. Here’s why.

In many essays on this blog, I’ve talked about how I consider many cider and heirloom cultivars to be very vigorous as compared to most of the grocery store cultivars. Vigorous cultivars are harder to prune, occupy more space (so less trees per acre), have issues with vegetative vs fruit bud proportions, etc. In general, they are harder to grow.  After reading more about this “plant vigor hypothesis,” I wonder if there is a connection between vigor and nutrient density in apples cultivars?

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From an evolutionary standpoint, a correlation between vigor and nutrient density makes sense to me. Many wild crab apples in the US have much higher tannins (aka polyphenols, which =nutrition density) than cultivated varieties. This is from the many lifetimes spent co-evolving with insects and herbivores who are trying to eat them. From observing crabapples in the “wild” and planted in landscapes, it seems as if many trees have low vigor and perhaps this is because they have evolved to have an unpalatable deterrence for animals and humans alike?

In hard cider, many of the wild crabs are too much for our palates to handle and though very nutritious, they will cause a harsh and likely negative consumer experience. So what have we done? Over time, cider drinkers/makers/apple growers have selected cultivars to grow which are palatable to the consumer, but also contain enough tannins (or polyphenols, or natural defense) to give the cider some substance.  Could it be that in selecting not-so-astringent apple cultivars for eating/drinking, we’re unknowingly selecting for more tree vigor? If the apple cultivar hasn’t evolved enough to deter herbivores through astringent taste, then do genetics dictate that it must rely on vigor to survive? 

These sorts of questions make me excited and I’ll keep learning about these processes in order to try and uncover different management ideas that don’t involve regulating vigor through the use of dwarfing rootstocks, black magic hormonal potions like Apogee (which converts vegetative buds into fruiting buds), and planting in light soils. All of those management aspects, I suspect, are making the vigorous cultivars less vigorous/more fibrous/less nutrient dense.

Thoughts to be continued, but in the meantime here are a few off the top of my head:

Thought 1: Pruning extremely vigorous varieties like an herbivore in order to get faster fruit set?

Thought 2: Continuing to fruit explore to find mixes of wild x cultivated which hit high nutrient densities, palatability, and lower vigor.  (I’m writing a fruit exploring book about how to do this at the moment)

Thought 3: Making crabapples a significant part of my home breeding program.

 

 

Stress: The New Bittersweet? (A Radical Orchardist Part 2)

It seems like it has rained every day for the past month in the Champlain Valley of New York and Vermont. Combined with 70-80 degree temperatures, the fungal population couldn’t be happier. It’s like one continual fungal feast over here, and I couldn’t be more psyched. Why? Because I’m absolutely infatuated with the idea of stress in an orchard.

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In A Radical Orchardist: Part One (which I encourage the reader to read before pursuing this essay), I re-introduced my thoughts about how apple scab, a fungal disease, increases the brix (sugar content) of the apple, which translates into a higher alcohol content once fermented. For hard cider purposes, I thought, perhaps we shouldn’t be spraying-late season fungicides for cosmetic fungal diseases like apple scab, since lingering fungicide residue has been known to kill the ferment (the yeasts) in the wine and cider realms. I also re-introduced the idea of managing apple scab as a value-added disease for cider apples, a thought that is about as radical as it gets these days in the apple world. A thought that I’m still excited to explore and understand in order to embrace it or dismiss it.

This year, I’ve been actively looking for scientific research on the effects scab has on apples, from a nutritional standpoint. I want to know how the apple reacts to scab; What does that fight look like? Does a stressing agent like apple scab bring about super fruits? This research is slow, mostly due to the fact that I don’t have access to any scientific journals, but it’s progressing and has me optimistic. The following is a report on my findings and thoughts.

Stress: The New Bittersweet?

My journey started when I found a paper about the effects of apple scab on the peel of an apple. The article, which can be found here and simply broken down here, stated that a peel covered with scab lesions is higher in polyphenols than one not covered in scab. What’s the big deal? Quite a bit, actually. This is a big deal. Screen Shot 2015-07-01 at 3.27.42 PMScreen Shot 2015-07-01 at 3.28.21 PM

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Phenols, such as chlorogenic acid (as seen in the top graph), are classified as antioxidants, meaning  that they tend to prevent or neutralize the damaging effects of free radicals in the body. Free radicals are chemicals that have the potential to cause damage to cells and tissues in the body.  Many of the phenols mentioned in the paper above are related to resveratrol (the polyphenol found in red wine which got a lot of news a while back for making wine drinking a life-saving activity). When researched in the skin of non-scabby red apples (aka: what you see in a grocery store), they were found to contain powerful antioxidant capacities, along with anti-cancer, anti-inflammatory, and cardio-protective properties.

Now, take those phenolic values from the skin of the non-scabby red apple and multiply them by at least 3+ times. That new value is one coming from an apple with scab infection. To further push this point, this article suggests :

The way in which orchards are managed can influence the amount of phenolics, as shown by Veberic et al. (2005), who reported that organically grown apples had somewhat higher amounts of phenolics as compared with traditionally grown apples. These authors concluded that this is probably because organically grown apples face more stressing conditions, for synthetic fertilizers and pesticides are not used.

Folks, this is superfood status and at the very least, people should try to source ugly organic apples and eat the peels. Research says that doing so might save your life someday.

Now, to project these findings onto cider…

What makes a cider apple a cider apple? The quick universal answer most people know is that it’s in the tannin. Tannin is a collection of phenols such as chlorogenic acid, phloridzin, epicatechin and the procyanidins (source). Only the procyanidins are considered “true tannins” because they have the ability to tan things like animal hides and give the drying sensation we recognize as astringency (aka: the sensation you get when you stick an acorn in your mouth). For the most part, bittersweet apples have the most tannins, or phenolics, and dessert apples have the least.

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https-::books.google.com:books?id=jZvqBwAAQBAJ&lpg=PA622&dq=plant%20polyphenols&pg=PA829#v=onepage&q=apple&f=false

A bittersweet apple, taken from this Serious Eats article, is described below:

If there is one style of apple prized above all others by American cider makers, it’s the bittersweet apple. Affectionately referred to as a “spitter,” these apples are low in acid, high in tannin, and impart the classic flavor of finer French and English ciders. At first bite, most would consider bittersweet fruit inedible. But what is ill suited for the fruit bowl is ideal for the cider press.

For the most part, America’s high acid, high sugar apple crop provides all the fuel for fermentation and puckering power necessary for a great cider. But what that fruit lacks is tannin—the molecules that impart astringency and provide a cider’s texture—and bittersweet apples fill this void.

https-::books.google.com:books?id=lATkBwAAQBAJ&lpg=PA106&ots=76WFijiMHz&dq=%22tetrameric%20procyanidin%22%20apple&pg=PA105#v=onepage&q=%22tetrameric%20procyanidin%22&f=false(image)

Ignore the yellow highlighting, and the column about gelatin

I hope your wheels are turning like mine were, but in case not, let me break it all down for you.

Cider apple varieties are known for their higher levels of phenolics, because those phenolics (aka tannin) distinguish them from dessert fruit. Those phenolics involved in making a cider apple a cider apple are also the same phenolics that increase in concentration when the apple is stressed with apple scab. If you refer to Figure 1 above, you’ll also see that in addition to high levels of polyphenols, a bittersweet apple is one with a higher brix. Let me remind this audience that this whole Radical Orchardist series started with the deletion of an article I wrote about how apple scab increases the brix in apples.

I’m no chemist, but it seems to me that stress has the potential to send some dessert varieties into the realm of a bittersweet. Now, how about stressing a cider apple? Is the increase in phenols due to stress worth it to the cider maker and the consumer? This study says that phenols in hard cider are absorbed, metabolized, and excreted by humans. Meaning, we’re getting the nutrients.

Screen Shot 2015-06-29 at 10.51.33 PM

phenolic content of apple leaves, healthy vs infected with scab. http://www.sipav.org/main/jpp/volumes/0108/010807.pdf

It makes sense to me. When stress occurs, the apple’s response is to pump the site of infection/attack full of phenolics (see graph to the right) . Look no further than your forest’s edge to find wild, highly evolved, inedible tannic crabapples that serve my point. The crabapples have evolved to contain these phenolics without provocation. The lesser-evolved dessert varieties, however, may need to be provoked through varying degrees of stress in order to produce a more nutrient-dense product, or one that more resembles a bittersweet cider apple.

What does this mean for management? Back in the first A Radical Orchardist essay, I irritated a few folks with the question:

What is a cider apple? Sure, you can have all the old French and English varieties like Dabinett, Frequin Rouge, Tremletts Bitter, Norfolk Beefing, etc, but if they are managed the same as dessert apples…are they really cider apples? I don’t think so.

And I still don’t think so. I believe that growing cider apples requires a completely different mindset than growing dessert fruit in order to make high quality, nutrient-dense, healthy organic hard cider. To me, a part of being a cider orchardist involves learning how to balance stress within the orchard through organic means. What do I need to give the tree in order to replenish the expense of fighting off an infection? What is the tipping point of too much stress? I whole-heartedly believe that these, plus many more, are the questions we should be asking. Imagine a world where the value of an apple comes not from its looks, but from its nutrient content. That’s what I’m aiming for with stress, and I believe there is value in that.

Please, those of you who are researchers…prove me wrong. I have admitted to the fact that I’m no chemist, and without academic ties, its completely reasonable that my understanding is flawed from the free book snippets and articles I find online. Send me a response with accessible PDFs, I’ll make sure to post it in a follow-up essay with reasons why I agree or disagree. Hopefully some great questions will come out of it and some university or private foundation somewhere will want to investigate.

In the meantime, the take home message is to #eatuglyapples and #drinkuglyapples. Embrace the scab, avoid the rot and challenge the status quo.

Postscript: Earlier in this essay, I included the following phenolics to define tannin. They were chlorogenic acid, phloridzin, epicatechin and the procyanidins. From this article, it states that apples infected with scab had:

  • 6.5 times more phloridzin than a healthy apple.
  • chlorogenic acid can be found in the first graph of this essay
  • epicatechin levels are in the following graph:
  •  Screen Shot 2015-07-01 at 7.26.50 PM
  • procyanidans are flavanols, which are widely cited by research papers to be the reason why some apple varieties are resistant to scab.