Rootstock and scion vigour

[Randommoose]

Hi,

Can I check I am understanding this right please? I am trying to work out what rootstocks to get for a mix of apples and crab apples.

I presume I need to consider
Rootstock - the general descriptions seem to say around M9 = 2m, M26 = 3m, MM106 = 4m
Scion vigour - Weak, average, strong - if I get a weak I need to go up a rootstock size to get to the same size as an average?
Climate/soil - I'm on clay loam, fertile, moist, doesn't waterlog, Gloucestershire, sun, sheltered - so pretty much ideal?
Pruning - A summer pruned form (eg cordon) will grow one size smaller than an unpruned or winter pruned form?
Organic growing - do I need to go up a rootstock size for this or is that only if the scion has poor disease resistance?

Example 1:
Oblique cordon - need a trunk diagonal height of 2.5m (1.8m high fence)
The height means M9 to M26, the summer pruning leads it more to M26 to MM106, (the fertile soil reduces that, the organic growing increases that so they can cancel each other out).
If the scion is weak growing then I would need MM106, if it is strong growing then M26, if it is average then either rootstock with MM106 needing more pruning in summer than M26?

Example 2
Crab apple, unpruned, I want a height of 2.5m.
The height means M9-M26, no change for pruning, fertile soil reduces, organic growing increases so they can cancel each other out.
The scion I am looking at is upright growing but "weak vigour", "naturally dwarfing" etc. So for this would I want M26 to MM106?

I know this is all very mathematical and there are so many variables and nothing is going to grow to an exact height but it helps me get an idea of what I need to look for.

Also, why don't fruit websites list the crab apple rootstock? They have already done it for all the other fruit varieties, why not the crabs?

Moose

[ameno]

I think I would advise against MM106 for cordons on your soil, at lest for all but the very weakest growers. It would be too vigorous.
You can't always just make up for the extra vigor with more pruning. Prune too heavily and all you do is encourage more vigorous leafy growth, and no flowers or fruit.

[nickdub]

back in the days after WW2 some growers noticed that trees planted on the sites where bombs had hit grew better than others in the same field - probably because the soil had been broken up to crack any hard soil lower down - mentioned for one in Raymond Bushes book on tree fruit growing from memory, any how I've often wondered if some one who had an explosives expert as a friend might like to try an experiment with TNT or similar :-)

My point being that the roots of trees can go a hell of a long way down maybe 15m + in some cases so subsoil for trees is important, but unless you can work it out from trees in your area its often hard to be sure what soil your tree roots might be finding

[Randommoose]

The subsoil here is clay with a yellowish tinge. The trees in or nearest my garden are a mature 6-7m Prunus Amanogawa, a silver birch probably about 12-15m, a lime about 15-20m etc. I've also got some beech hedging, a topiary beech tree and in the front a unknown wild cherry about 10 years old. All very healthy. A little further there is an unhealthy horse chestnut and various other healthy trees including ash, a massive specimen conifer and loads I don't know what they are. Lots of big mature trees around here.

[Randommoose]

I think I would order the cordons on M26 as the varieties I'm planning are average vigour.

The crab apple is normally only available on MM106 as it very weak vigour and the couple of places I've contacted have said it will only make 2.5m. My most local nursery supply it on M27 apparently which seems tiny so I've emailed them to confirm if that is correct.

[Babru]

I hadn't realised that you could get grafted crab apples. I thought that as they weren't particularly large they came on their own roots. Interesting! I'd certainly like to know what the rootstock is if I were buying one.

[nickdub]

I hadn't realised that you could get grafted crab apples. I thought that as they weren't particularly large they came on their own roots. Interesting! I'd certainly like to know what the rootstock is if I were buying one.

Yep, they're just apples - you can graft a branch of a crab apple you like which a friend has on to any of your apple trees - also vice versa if you have a crab apple tree you can graft dessert or cooking apple varieties on to that. Back over 80 years ago or more back into Roman times apple varieties were grafted by our forebears on to crab stock very commonly, as crab is more dwarfing than just growing trees on their own roots

History of Fruit Growing – Wiltshire Gardens Trust

https://www.smithsonianmag.com/arts-...ier-180953263/

academic approach :-https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3606516/

books - hint Xmas present territory :-) :-

https://www.amazon.co.uk/Apple-Orcha...s=books&sr=1-5

https://www.amazon.co.uk/Fruit-Sands...s&sr=1-1-fkmr0

https://www.amazon.co.uk/Potted-Hist...s=books&sr=1-1

The American Fruit Culture (1863), John J. Thomas (1810-1895)

[Babru]

Thanks for this nickdub. I'd no idea Johnny Appleseed was a (sort of) real person. And a religious aversion to grafting! Good job that's not common now, or most people wouldn't have space for apple trees.

I don't have any apple trees as yet, I'm reading up to find two suitable ones to plant next year.

[nickdub]

Thanks for this nickdub. I'd no idea Johnny Appleseed was a (sort of) real person. And a religious aversion to grafting! Good job that's not common now, or most people wouldn't have space for apple trees.

I don't have any apple trees as yet, I'm reading up to find two suitable ones to plant next year.

no worries - give me an idea of what sort of apple you like ie cookers, early eating apple, late keeping apple, and I'll do my best to help you by suggesting some possibles :-) - you have to watch out for pollination problems, but often trees in neighbours' gardens can help - bees aren't bothered by who owns a tree.

[Randommoose]

Thank for this advice before (two years ago now!). In the end I went for:

Cordons on M26:
Discovery - smaller than the rest but healthy and pest free. A couple of apples last year, but all shrivelled and dropped in July this year.
Saturn - doing brilliantly. Healthy, leafy, big pest free apples, not quite ripe yet.
Red Sentinel crab - doing well, pest free, was a year younger so smaller than the others. Flowers and fruits well
Ashmead's Kernel - very prone to pests, no flowers or fruit this year, last year all destroyed by pests or rot. It is vigorous but not much bigger than the others as so many leaves die due to pests.
Topaz - doing well, healthy, pest free, fruited well both years (not ripe yet this year)

I also got the very dwarf crab (Admiration/Adirondack) on MM106 grown as a bush/half standard. It hasn't yet increased in size! Healthy and fruiting but not put out any more branches or length.

In the front garden I have 2 bush grown apples I planted the year before writing this thread:
Cevaal on M26, sturdy, healthy and vigorous but short, fruiting well, tasty
Red Falstaff on MM106 - healthy, fruiting well and tasty but not growing very well. I have staked this now as it kept leaning over. I also thinned off three quarters of the apples as it was growing too many. I want it to get stronger and bigger as this is supposed to be the biggest tree of them all but it isn't growing as fast as the M26 based trees. The Cevaal is bigger even though it is on a smaller rootstock and a year younger.

I also have 2 plums on St Julien A:
Winterbourne Magnum - very upright and whippy growing. Tasty fruits, not many yet. Healthy and vigorous.
Santus Hubertus - spreading and smaller. Fruited lots last year but quite sour, none this year. Medium health and vigour.

They have all had a couple of seaweed fertiliser this year and have woodchip mulch. I watered them the first year but not this year except when extremely hot I did once or twice a week. The aphids haven't been too bad this year. I don't do anything about them unless it is a very young tree that is badly affected. Now mine are all big enough I don't bother doing anything and they outgrow the damage if there is any.


The Ashmead's Kernel, Discovery and Sanctus Hubertus are probably going to get one more year to see if they improve and if not I will probably remove them and replace with something else.

[Randommoose]

Update another year later in case anyone in the future is interested in these varieties and their growth etc.

Cordons on M26:
Discovery - still smaller than the others, has been getting some pests this year, again all apples shrivelled and dropped in July so this one is pointless to me. Almost certainly going to be removed, just I can't currently dig due to an injury.
Saturn - same as last year - doing brilliantly. Healthy, very leafy, really big pest free apples. Juicy and mild taste.
Red Sentinel crab - same as last year - doing well, pest free, Flowers and fruits well. My child likes eating these as much as the eating apples!
Ashmead's Kernel - extremely prone to pests, still not had a single normal size apple from this one, they either fall off or get damaged and stop growth at about 1 inch big. I did get one about 2 inches, it was mealy and dry. Almost certainly going to remove this tree as well.
Topaz - same as last year - doing well, healthy, pest free, fruited well. Very late fruits that hold on the tree well. These are my dog's favourite so he has picked and eaten most of them!

Removing the Discovery and Ashmead's Kernel will give the other cordons a bit more space. I had been advised to plant them 60cm apart when I got them but since learnt here that further apart is better.

Very dwarf crab Admiration/Adirondack on MM106 grown as a half standard has put out a branch about 2ft long - that is the only growth in 3 years, they really mean it when they said naturally dwarfing! It is healthy and fruits very well, fruits are still currently on the tree in mid January even after all the -7 weather.

Cevaal bush on M26 - healthy, very stocky (thick branches but short) fruiting very well, tasty.
Red Falstaff bush on MM106 - healthy, fruiting well and tasty (my favourite). This one didn't grow much and kept leaning over the first couple of years but with staking and lots of thinning fruit it has now got sturdier and is holding itself up and growing more. I still put a temporary stake when the apples got big just in case. Removal of the 5m tall self seeded cherry tree seemed to help so I think there might have been a cherry root underneath.

I also had 2 plums on St Julien A:
Winterbourne Magnum plum - was healthy and vigorous, not fruiting much but quite tasty. Removed because of garden changes in that area and came up with enough root ball to give to someone else to plant to see if it survives.
Sanctus Hubertus - another year of this being plagued by aphids (most upper branches bare with leaf loss), hardly any fruit and those were sour so it has been removed.

No watering this past year except a couple of buckets in the long drought. I don't remember if I did any fertiliser so probably not. I didn't remove any aphids as they can all outgrow them now but I take off damaged fruits to avoid rot spreading. I keep meaning to put some sacrificial nasturtiums in to take the aphids but keep forgetting. Though Ashmeads Kernel gets other pests none of it spreads to the other trees even where they are touching. The pests just like that one particularly!

I've done a lot of other planting (trees and shrubs) this year but no more fruit trees. I will have a think if I want any replacements for Discovery and Ashmead's Kernel but put them elsewhere if I do. I would still like to grow a russet variety. The garden is gradually being planted up and in the future after a shed build (hopefully later this year) I might have a suitable space for an espalier, fan or more cordons. So maybe I could get a russet for that. No idea what variety though. Ashmead's Kernel is the local variety (Gloucestershire) and that hasn't worked out.

[Snoop Puss]

Really interesting read, Randommoose. You're far more careful a tree grower than I am. I should take a lesson from you. Hope you have a great year for fruit this year and good luck with your shed.