Interstem questions

I remember an old thread on GW about interstems. At the time I didn’t care, but now have some interest. So like M111 and Bud 9, what is the experience on dwarfing effect vs length of Bud 9? Also, do you plant the lower graft below the soil line? Why?

My new apple interstem trees are on that same combination of M111/B9. I currently have 3 pear and 1 apple with long dwarf interstems planted and they are doing well. These are on standard roots. They are enjoyable to create and might actually work well for early fruit production, drought tolerance, and keeping the tree size down. Good luck Bill

Some years ago I got a few interstem (different combo)trees from cummins. I was asking the same kinds of questions here is what Jim cummins sent back:

"We strongly recommend that trees on G.11/MM.111 interstems be planted
with half the interstem G.11 exposed above permanent soil level, half
below soil. This permits the G.11 to take root and the tree to
develop a dual root system. The precocity and productivity induced by
G.11 as a rootstock should be slightly diminished. The MM.111 will
provide solid anchorage; staking will not be necessary for tree
support (although we do recommend temporary support to facilitate
building canopy).

We expect ultimate tree size to be about that attained with Malling 26
– without the problems of fire blight, crown rot, and burrknots.


Some folks back then on gardenweb thought perhaps he was trying to avoid burr knot issues by burying the lower graft.

Hope thins helps some


I made some interstems last year, bud 9 on antonovka with golden russet as the cultivar. Bench grafted two whip and tongue splices with about 8" of interstem. I got 90% take. I plan on doing around 100 more this year since it worked so well.
I think I’ve read that burying half of the interstem helps prevent the rootstock from suckering.
I’d love to hear more folks experiences who have had interstem’d trees in production! The benefits seem like this should be a more mainstream practice.

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JesseS. It would be nice if more information was available on this topic. Interstems might just be a little complex and time consuming for commercial people to use. I think in most cases if they are going to invest the time and money they will go with the old tried and proven method. For me with just a few trees in the back yard I have very little to lose if I error. Good luck with your next 100. Bill

The USDA is a great source of information on rootstocks and you will find their research and knowledge on the subject is extensive The original question about interstocks aka interstems has been around awhile and you might be interested in a historical document“interstem%20commerical%20apple” the research continued“interstem%20commerical%20apple”
At this link you will again see confirmation of the widely known “EMLA 9 / EMLA 111-This interstem combination uses the dwarfing growth habit of the EMLA 9 with the benefits of the EMLA 111 root system.
BUD 9 / EMLA 111-This interstem combination uses the dwarfing growth habit of the BUD 9 with the benefits of the EMLA 111 root system.” Cornell and others mention similar information "M.9/MM.111 Interstem – An interstem tree consists of three parts: the scion variety, the interstem piece, and the understock. M.9/M.M.111 has all the advantages of M.9, but a stronger root system and somewhat better drought tolerance. Should be planted deep, with only the interstem piece showing. "
Ok so now onto the interesting stuff. This link‘Fuji’_Apple_Quality clearly states the interstem has a signifigant impact on fruit size. It’s also widely known rootstocks have an influence on fruit taste, texture, mineral content etc. The article I just referenced states “In 1989, an 8-yr-old commercial block of ‘Granny Smith’ and Oregon Spur I Delicious’ apple trees on M.26 rootstock were grafted over to ‘Fuji’ (Nagafu 6). Before grafting, the original trees were cut back to 90 cm, leaving 20–25 cm of the original scion to serve as an interstem. In 1991 through 1993, 1 to 2 days before commercial harvest, 20 apples were harvested from each of 20 trees of each interstem treatment selected randomly throughout the block. Fruit characteristics (firmness, color, soluble solids concentration, acids, fruit weight, physiological disorders, and mineral content) were assessed on half the apples at harvest and on the other half after 120 days at 1 °C. At harvest, apples had similar starch levels regardless of interstem, but interstem effects on fruit quality were significant. ‘Fuji’ apples from trees with ‘Delicious’ interstems were larger, and had more acidity and more bitter pit than apples from trees with ‘Granny Smith’ interstems. ‘Fuji’ apples from trees with ‘Granny Smith’ interstems were firmer with more red color development and higher soluble solids concentration than apples from trees with a ‘Delicious’ interstem. After storage, ‘Fuji’ apples from trees with ‘Delicious’ interstem developed more scald than apples from ‘Granny Smith’ interstem. Fruit-flesh Mg, P, N and K; fruit-peel Mg, K, P, N and B; and leaf P, K, B, and N were greater in ‘Fuji’ apples with ‘Delicious’ interstems compared to ‘Fuji’ apples from trees with ‘Granny Smith’ interstems.” . Rootstocks typically used can be referenced here . This is a summary of what influence the interstocks have Characteristics of Apple Rootstocks and Interstem Combinations


I plan on doing some B9/B118 this year, and also have some G222 coming. I will graft high on either interstem or G222 in coming years and this year focus mainly on getting the 2 into nice tall whips.

On Gardenweb I did some research on interstems in the past, I believe as little as an inch or so of interstem is enough to induce dwarfing (albeit a compromise due to the non-dwarfing rootstock as well) but many people recommend 6 inches or more just so you can bury part of the interstem as well–that’s why I wanted to grow my B9/B118 out another year, I want 12-18" so I can bury at least six and still have thick enough wood to graft and keep the union solidly above ground.

Of course I could be doing something totally wrong…

I like this guys blog/videos on interstem apples.

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Anyone has experimented Interstem Rootstocks: B118/B10 on apple tree? Good results?

Hi! I understand this is an old post. But i made a profile just to get to talk about this. I have grafted 30 interstem trees of bud9/antonovka this year with different cultivars. How are your trees doing now? did you plant them with the lowest graft below the soil line. And did all survive? Greetings Thomas


Welcome! All my interstems are doing well, replanted with the lower union below grade by a couple inches.


Has anyone noticed more suckering from the rootstock when there is a dwarfing interstem? It seems like this could happen with the growth potential of the more vigorous rootstock being impeded by the less vigorous interstem.

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My callery root with dwarf interstems have no suckers but the M111 root with Bud9 interstem has put out a few suckers. I’m not sure but I think the M111 puts out suckers without interstems. Recently I planted two M111/Bud9 interstems with the graft union below the soil line which might eliminate the suckering.


I ordered a bud 9 this spring with plans on using it in the future for interstem material. When it arrived I snipped a piece off the top and grafted it on a seedling apple . It is looking nice , I think I may put pristine on this one.


Interstems are fascinating and not well understood. At face value we get fruit like normal but in the case of my pears the interstem and rootstock has much more influence than most people would care to hear about. They influence growth, color, vitamins and minerals, storage etc…


I never thought much beyond tree size, early fruiting, and drought tolerance using interstems. Not an exact correlation but my one standard pear tree has progressively produced better tasting fruit each year. I suspect it will take longer for my dwarf interstem pear trees to achieve a similar quality. Many unknowns about growing fruit.


Bill ,
one of the many reasons I grow full sized trees is the fruit has tasted like its better quality to me. If we think about it reasonably in Kansas the top 3-4’ of dirt were farmed very hard raising grains , cattle etc. .the big trees are pulling nutrients from 30 feet down. Which would you rather eat a pear raised in the top 8 feet of soil or the one raised with roots 30-40 feet down? The big standards produce more pears in the same space, are more deer tolerant, pull nutrients from deeper, are more drought tolerant because as the water table falls the roots are deeper etc… the interstem can have as much influence as the rootstock on growth. If we could afford it and did a laser burn test to find out the nutrients in the fruit I’d bet we’d be shocked at the differences rootstock and interstem made on the minerals detected in the burn test.


I was pointed to this thread with a pear question- but this snippet from Cummins has me thinking. Do you think this G11 interstem would work on another root- say G890? Those are what I would have to work with now, could order something else to try. P18 or B118 or Antonovka are also deep rooted, but too large for my space. I’d love to try, I want a more drought-resistant freestanding orchard.

Alright folks - I am going there. I know this thread has focused on apples and pears, but what about other “non-traditional” fruit? I am particularly interested in if anyone has tried an interstem for pawpaws?

Obviously disease resistance/dwarfing characteristics aren’t as important as with apples and pears. I am particularly interested in passing traits such as high vigor onto less vigorous cultivars. I was thinking mainly about using ‘Mango’ to possibly reduce the years to bearing fruit for other cultivars as KSU Chapell is patented and I’m not sure on vigor compared to ‘Mango’ for others like Kentucky Champion and Regulus (two others that might fit the bill). So has anyone tried it, and any good results? @Barkslip @TrilobaTracker @Blake @RNeal @mamuang @PharmerDrewee or anyone else?

Are there any other specific traits that I’m not considering that I should be? Am I over-thinking this?

Interesting information.