M116 Apple Rootstock

M116 is a cross between MM106 and M27, and seems to have the best qualities of both.

M116 is not widely available. As you have noted, this is partly because it is difficult to propagate.

However another significant reason is that cider has become fashionable and at the same time the cider industry has latched on to the productivity benefits of less vigorous rootstocks (about 50 years after everyone else!). M116 is seen as the ideal rootstock for modern cider orchards and the result is that the vast majority of M116 production for the next 2-3 years has already been bought in advance by cider growers.

Taking the ancestry further back:

M116 = ( (N.Spy x M1) x (M13 x M9) )

M116 = medium vigour. 60% full size.
MM106 = medium vigour. 40-80% full size; very variable depending on soil and climate.
Northern Spy = medium vigour. 60% full size when used as a rootstock.
M9 = dwarf. 30% full size.
M27 = extremely dwarf. 20% full size.
M13 = vigorous. 80% full size.

Other common rootstocks, as reference points:
M26 = semi-dwarf. 40% full size.
M25 = very vigorous. 90% full size.
M16 = extremely vigorous. 100% full size.
MM111 = vigorous. 80% full size but will match full-size trees and very vigorous rootstocks in difficult conditions (because the full size trees and the other vigorous rootstocks won't cope as well as MM111).

Note that "full size" is a bit misleading because the average seedling is about 70% full size and generally similar in vigour to M116, MM106, N.Spy, MM111 and M13. Look at seedling apples growing alongside motorways: they're often medium-sized bushes and nothing like the mighty "heavy standard" trees we might see in old orchards.

The most vigorous seedlings being 100% full size. Just as some humans can be 7ft tall, but most are in the mid-5ft range and therefore about 70-80% of full size, so to speak.

FB, I have to ask, considering how troublesome MM106 seems to be in your location and soil type, why do you bother with it? From reading your posts it seems to be the source of a LOT of frustrsation.

Other than it's ease of rooting from a cutting, what would your say it's plus points were?

As time passes, I manage to do more little experiments and have more observations of the trees.
I think MM106 is troublesome for me because:

1. I have light sandy soil which doesn't hold much water.
2. I live in one of the driest parts of the UK.
3. MM106 grows much slower in drier soils and gets stressed.
4. A stressed plant is more likely to succumb to disease.
5. Because the MM106 is stressed in my soil it doesn't grow well.
6. Because it doesn't grow well it gets watered.
7. Too much watering can lead to fungal diseases of the roots.
8. Water from water butts is more likely to contain fungal diseases which, when given to stressed plants, causes them to become sick.

So putting all the above together explains some experimental results I got in summer 2013:

I had a variety of young rootstocks (M9, M26, M116, MM106, MM111, M25) in pots or in the ground with grass cover or in the ground with a 1ft clear area around the trunk.
As is usual for us here, we had a dry spell in summer and the plants began to wilt (it was dry enough to actually kill a handful of pears on seedling rootstock which were not part of this experiment).

When the plants wilted I watered them using water from my water butts (tap water is not as easy to cart over to my fruit trees but water butts are nearby). I poured butt water on the shoots and leaves of the plants, and being summer it probably dried off the foliage within an hour, yet I found that the twigs and branches soon developed crown rot symptoms - lots of points of infection - and in many cases it spread through the tree within a few months and killed the tree.

As I had previously found: MM106 is very susceptible, but I also managed to kill a surprisingly high number of MM111 trees and M25 trees as if they had no resistance. M116 and M26 rootstock was partially resistant. M9 has good resistance.
Of course, the key thing about this test was that it showed any medium to vigorous rootstock under stress makes both itself and the scion susceptible to disease. I doubt that it's just Phytopthora crown rot that they're more prone to because I see a lot less mildew on my MM111 and M25 trees than on my MM106 trees.

Other tests that I've done show that growing a tree with grass all the way to the trunk seems to make much more resistant to fungal diseases attacking the roots. However, only MM111 and M25 reliably have the strength to compete well with grass and if MM106 is grown in grass it can become stressed or grow poorly, except where soil moisture/rainfall is not in short supply. Don't underestimate how much water and nutrients a layer of grass intercepts before the tree roots do; competition from the roots of grass in the top few inches of soil forces tree roots to grow deeper, where they will be in poorer soil than the grass. Soil quality is best near the surface and gets progressively worse deeper down.

In summary: MM106 gets stressed under my dry conditions; more so than the more vigorous M25 and the known-to-be-tough MM111. And being stressed makes a tree more prone to infection. Being less stressed makes a tree more resistant to infection.
At the other end of the scale, dwarf rootstocks show some resistance, which is probably due to their tendency to have thick bark and less burrknots, making it more difficult for fungi to breach its defences or find a weak point.
Burrknots are cracks in the bark where roots emerge, but cracks also allow fungal attack; however, after several years burrknot mostly go away and the bark thickens which makes any rootstock much more resistant to attack.
So if you can grow MM106 in a low-stress situation (and get it past the vulnerable first several years when it has burrknots and thin bark on a small young tree) it will probably be satisfactory and perhaps no more prone to root disease than any other rootstock.

As for plus points of MM106:

Resistant to woolly aphid.
Can be used for almost any tree shape or form without staking, providing the soil is to its liking (i.e. not prone to drying for long periods every summer).
Copes better than other rootstocks in cold, damp soil (but only has average winter-hardiness and doesn't like being in saturated soil). In cold, damp soil there may not be much difference between MM106, MM111 and M25.
Encourages the scion to produce good strong branch angles.
Will fruit at quite a young age if suitably managed with minimal pruning (hard pruning will invigorate MM106 causing growth but no fruit).
Its wide-spreading roots will tolerate drought once established (but may not be able establish in drier soils).
Good anchorage (although anchorage may be poorer if allowed to fruit too much too early in its life).
Less prone to bitter pit than other rootstocks when grown on slightly acidic soil.

So what would you say would be a balance between these two points? I'd guess in most domestic situations growers want both; good anchorage and a sturdy tree, and fruit bearing asap.

That's interesting. I would've thought the opposite to be true ie. close proximity grass retaining damp and restricting air flow.

Yes, that's been the one constant throughout any discussion or article concerning this rootstock. Do you think Phytopthora is more of a threat to a new tree in winter, when the tree is dormant, or summer?

Following the relentless rain in recent weeks in the south, we're not flooded where we are thank goodness, but the ground does have the consistency of pudding, and has been that way for some time. I'm wondering how that will affect my young fruit trees.

Thanks FB, great info as usual.

The fruit from a fast-growing young tree tends to be poor quality. So let the tree grow new roots and some more branches and get it shaped-up by winter pruning for the first couple of years.


Phytopthora lives in the top few inches of the soil and attacks trees between the soil line and six inches below the soil. But if there is a mat of grass in that area the tree roots will be forced to go deeper and therefore mostly out of the Phytopthora zone. I guess in nature a tree doesn't have someone kindly clearing away the grass and weeds around it, so roots of young trees immediately below the soil surface might not be "normal" in nature (older trees have thicker bark and are less susceptible, so when their thick old roots rise out of the soil the bark is too thick for fungi to easily penetrate).


Fruit trees are most at risk of Phytopthora infection when the leaves and shoots are growing because Phytopthora likes to attack stressed trees (and either drought stress or near-drowning will severely stress the roots).
So they are most at risk from a few weeks before leafing-out to a few weeks after dropping their leaves. Spring and autumn are the most likely times for infection but it can sometimes happen in summer too.
When the tree is dormant (roughly December to March) its roots are not under much stress because the leaves are not calling for water and nutrients, so in winter trees are more resistant.

Sometimes a tree can be infected in the nursery (nursery soils have grown the same plants for many years - the soil becomes infested with diseases which is why we rotate vegetable crops), so even if given ideal conditions it is already infected and will eventually die, often taking a few years after planting before it drops dead, although sickly trees tend to grow poorly.
Nowadays if I plant a tree and it doesn't grow as expected, I assume it is sick and remove it to save years of frustration waiting for it to decide whether to start growing or die.

Having read about the advantages of M116 rootstocks here, I thought I'd try to buy some and compare their performance with MM106, the rootstock I generally use under my wet soil conditions in West Wales (where it does pretty well compared with M26).

In case anyone's interested in searching for suppliers, the only nursery I've found on the internet willing to supply small numbers of M116 (multiples of ten) is 'Fruitandnut' in Ireland. See link below:

Specialist fruit and nut tree nursery supplying cobnut, walnut, chestnut, heartnut, apple, pear, plum, cherry, damson, apricot, quince, medlar, blueberry, mulberry, sea buckthorn, aronia, honeyberry and amelanchier varieties suitable for the Irish cl

They have an interesting collection of nuts and have been very helpful.