Waiting for the blizzard, thinking about apple interstems (ME coast, 5b)

Here in Maine we’re expecting 1-2 feet of snow over the next 36 hours, so as a coping mechanism I’m thinking about the trees I want to plant in the spring. I’ve read some of the threads here on interstems, and my friend Holly down in MA (who intro’d me to this forum) has used them for the espaliered trees in his backyard orchard with mixed success, but it would be great if folks have specific advice or experience to share.

By way of background, over about 10 years I’ve planted an acre of apple trees on a (bridge-connected) island in the midcoast region of Maine (z5b). The site is an old farm of mostly ledge and swamp, with some pockets of decent soil where my mom and grandfather grew apples, pears, berries, and vegetables. Twelve years ago Holly and I started making cider every fall; fortunately at the time my wife and I lived very close to Poverty Lane/Farnum Hill in New Hampshire, so we had access to an amazing assortment of Old and New World cider varieties, as well as bits of advice from Steve Wood and his crew. In the years since, we’ve refined a system of bicycle-powered equipment that cranks out serious quantities of cider so long as we have plenty of folks to pedal. Last fall we processed four 15-bushel bins in a day, and made over 200 gallons of fresh cider. (We don’t ferment it all; most of it goes home sweet with the pedalers.)

To feed this habit with apples, about 10 years ago I started an orchard on the land where I grew up, clearing a NW-facing acre of mixed second-growth trees over a few years and planting a wide assortment of varieties we’d come to use for our cider. My nursery stock came from our local co-op, Fedco, which back then sold everything on Antonovka seedling rootstock. Per Fedco advice (at the time they were saying 25-30’ spacing), I planted in rows 30’ with 28’ in-row spacing. The trees grew well but it was clear that they were going to take a long time to fill in the rows. So I started planting peach trees between the apples in the rows, which has worked well as the peaches seem sort of disposable - they grow fast, fruit young, and die unexpectedly, often with weird rubbery jelly coming out of the bark in places (which I take to be some kind of fungus). The foggy marine climate seems to hold the flowers back in the spring so they don’t get zapped by frost so often; on the other hand the later varieties don’t always ripen by fall; the best one for us has been an early one Fedco calls Lars Anderson.

Along the way I took a grafting class at MOFGA taught by Delton Curtis (who grafts many of Fedco’s trees) and got to where I could reliably whip-and-tongue or bark-graft apples, and summer T-bud peaches (though not vice-versa). We haven’t had a lot of problems with pests; occasionally voles get behind the wraps, and borers are a constant battle, but with vigilance we haven’t lost more than a tree or two. Pollination is more of a challenge, with long winters and most of the island grown up to forest, it’s hard to keep bees alive; I’ve taken to planting buckwheat between some of the rows and hope to do better with bees in the future. I haven’t started spraying, but now that we’re getting fruit of course it’s wormy; we don’t care as much since it’s going for cider, but I would like to get reasonably clean fruit, so I suspect this spring or next I’ll be looking for advice on spray regimens.

I started with seedling rootstock under the influence of Fedco, and because I liked the longevity and robustness of the full-sized trees, but the first batch are just now coming into bearing, and we aren’t getting a ton of fruit yet. So having crossed the 40yrs benchmark, I’m inclined to try some modern rootstocks to see if we can get more fruit sooner - as much as we love making the pilgrimage back to Poverty Lane every fall for a bin of bittersweets, I’d like to get clear of the carbon footprint. So last fall we opened up another quarter-acre, and I’ve picked out a bunch of varieties (some familiar, some new-to-us) to plant.

I’m interested in interstems because I don’t want to have to baby the trees too much; I live an hour west of the orchard, I’ve learned it’s all we can manage to water in a handful of trees semi-consistently in the first year after planting - after that they’re on their own. Apples grow wild here, and I don’t want to have to build a complex automatic irrigation system to get through August, which is the only month that’s dry more often than not. I also have limited capacity for mulching and weeding - the rows get bush-hogged ~3 times a year, but I’ve found that a half-yard of wood chips dumped haphazardly around the base of each tree with a tractor and a couple passes with a string trimmer are as much as I can manage in a season given other responsibilities. So I like the idea of a tree that combines precocity with a solid root system that can find the water and compete with the grass that makes it through the mulch.

Back before the Fedco discount deadline this winter, I ordered 10ea of B118 and M111 for the roots, and a bundle of B9 for interstems; I’m new to this but I think I saw that the B118/B9 combination had worked for folks, and it seemed like it should give a tree that’s substantially smaller than the seedling and B118 stuff I’ve been planting. Folks here and elsewhere seemed to think highly of G935, and Cummins appears to sell it by the piece, so I was thinking of putting it on the M111; as best I could tell this would make a somewhat larger tree than the B118/B9 interstem? I would really appreciate anyone’s advice on this subject, and particularly:

Do the B118/B9 and M111/G935 combinations make sense?

If so, what kind of in-row spacing would make sense in a cool coastal New England setting? Or if not, what combinations would you recommend to achieve the goals I’m lined up on?

What is the preferred length (or range of lengths) for the interstem?

Relating to how to actually execute the interstems, I was thinking to wake up the base rootstocks in the basement for a few days with the interstem rootstocks and scionwood in the fridge, then do both W&T grafts at once and let them callus up in the basement for a couple weeks before planting out. Or I could do the interstem graft, let that callus for a couple weeks with the scion in the fridge, then do the second graft, but I fear I’d damage the weak bottom graft trying to do the second one so soon. The guy who writes the Skillcult blog indicates that both grafts of the interstem can be put on at the same time. Have other folks found this to be true as well? It would be great if it wasn’t a two-year process.

This is a great forum; thanks so much for any advice!

Ben

Thanks for the intro on your fruit growing endeavors, I’m doing similar work about an hour inland in the westrrn foothills. I’ve made some interstems using B118 and antonovka as the stocks and B9 as the interstem section over the past three years. I’ve done them all in one grafting operation, as you describe as the first option, and similar to skillcults demo. I have tried to make the interstem section at least 7" long, and have another batch with longer 1’ sections. These are mostly still in nursery rows, so not much to report yet as far as precosity, but they’ve grown well…I expect them to get to about 50% of standard size, spaced 10-15’ apart depending on the cultivar vigor.

It depends on how you plant the trees. Some people plant the interstem half below ground so that the interstem can root. Supposedly this will improve precocity while retaining the long-term advantage of a larger root system. Obviously you need longer interstem for this method.

Last year I grafted interstems in 2 stages because I wanted to make sure the root-interstem graft was a success before risking the loss of limited scionwood. I didn’t have any issue with breaking new grafts. I did, however, leave the grafting rubbers on for additional support.

My understanding is that planting the rootstock/interstem graft union underground is preferable because this reduces future suckering from the stock. There is said to be some correlation between interstem length and the dwarfing effect, not sure exactly what that is however except that the longer the interestem, the more dwarfed the resulting tree will be.

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I planted several interstems from Cummins and don’t like the M111/G11 (G11 is the interstem) combo. I thought that it would have a strong root system and grow a bit more than a G11. Instead, they have all been somewhere between M27 and B9 in size (most closer to M27, which is a mini-dwarf stock). Most haven’t been too healthy, with bark problems around the unions. I think 2 of the 6 with that combo are still reasonably healthy, while at least 2 have already died, with 2 more on the way. I was just looking at one of them the other day and decided to pull it out and try to graft the (iffy) wood to another tree. I’ll probably just put a jujube in its place.

In contrast, the one tree that I have on B118/B9 (B9 is interstem) has done very well. It is a bit bigger than a B9 would normally be, around a G11 in size.

Note that I wanted my trees on the smaller size, so the interstem is completely above ground for all of them. It worked with the B118/B9, but not the others. I think my dad also planted some with interstems, so I should ask about his experience with them.

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I’m growing about 20 apple trees with M111/Bud9. This is unconfirmed but I think you need the longer interstems to gain the full dwarfing 14-15". My interstems vary in length. If your a careful grafter you can graft both sections at the same time and get a high take rate. M111 tends to sucker so planting the union a little below soil level should help. My three pear trees all have the long dwarf interstems 15-16". Good luck, Bill

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Awesome, thanks all for your advice! Glad to hear that the B118/B9 combo has worked well, and sorry that the 111/11 hasn’t - maybe this is part of the problem that Holly has had with his interstems (which I think came from Cummins…)

It’s great to have a starting point (10-15’) for in-row spacings; I don’t have much frame of reference for dwarfs (dwarves?). For reference, Fedco says to plant M111 at 15-20’ and B9 at 5-10’ spacings.

Based on this input I will aim for at least 8-12" or so of interstem, and plan to put at least some of it below grade.

Any New Englanders have experience with G935? I’ve never seen a WAA, which seems to be their noted weakness, though our hemlocks are dropping like flies from the adelgids.

Jesse - I’m picking up at Fedco this spring, if you are likewise I’m happy to pick up for you and shorten your trip. Enjoy the snow! At least it’s fluffy so it shouldn’t damage the trees.

Thanks again!

Ben

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I have Kidd’s Orange Red on M111/G.11. I planted it before I knew anything about burying the union of the root/interstem. I planted it at the soil line of the M111 root as it came from Cummins. Its a vigorous tree for me. I accidentally transformed it from a central leader tree into a bush tree last year due to a branch spreading mistake. It grew 4’ of new leader last year.

My dad has a Honeycrisp I gave him from Cummins on the M111/G.11 combo. It is much less vigorous, but not unexpected for HC, which is a weak growing scion. Also something that I learned later.

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Levers - thanks for the note about the variable vigor of different scions. I have noted different levels of oomph in my orchard but since I only have 1-2 of each variety, it’s been easy to write it off to soil variations or different levels of borer damage. Sounds like I should pay more attention as I start dwarfing things.

@fiveio - I found this from Starks. https://www.starkbros.com/downloads/AppleOrchardPlanning.pdf

At the bottom it rates relative vigor of different scion varieties. I’m not sure how much I put stock into it though. Some seem right to me, and others not. For me Zestar! >= Enterprise in vigor (both M7), but Williams Pride is very vigorous on an M7 size Geneva root (G.890, so that seems right).

The Home Orchard Society has a more extensive list: http://www.homeorchardsociety.org/growfruit/apples/estimated-tree-vigor-for-apple-varieties/

I would say that some varieties are well known for their low vigor, and they usually turn up in descriptions as “naturally dwarf”, “weak”, “low vigor” or sometimes “easy to maintain”. Dabinett is the one for me that matches that description to a T. Except for easy to maintain, a tree that won’t grow doesn’t do what it is supposed to, which is produce fruit.

Thanks for the offer to carpool Fedco orders…I will be there anyway as a vendor, we could meet and talk interstems face to face!
We got around 16" out of the Sunday-Monday storm, and holy snowballs, another dumping of 12-24" tomorrow?!?

Does anyone know a nursery that would still sell rootstocks this late in the season?

The interstems I made based on this discussion had been growing happily for several years, and some had started to fruit, but last fall disaster struck - perhaps because of the drought, mice girdled close to a dozen of them before we managed to get the spiral wraps on for the winter.

Normally I would order from Fedco or Cummins, but Cummins is out of most varieties, and I can’t pick up at the Fedco tree sale because it’s not on this year. I’d be very grateful for any ideas - thanks!

It’s late to order and most places either have low stock levels or are completely out of stock.

Raintree nursery still has inventory, Grandpa’s Orchard has low inventory and Maple Valley Orchard’s is completely out of stock.

Will Fedco be holding their tree sale this year?

No tree sale at Fedco this year

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Thanks mroot - looks like I could pick up some antonovka at least. The first trees I planted in my orchard were on Antonovka (under the influence of Fedco); I don’t have a sense of how that would compare to 111 and 118 as a base for an interstem - do you?

Thanks again!
BP

I think Antonovka would work fine for the roots of an interstem tree. However, I haven’t seen any one actually use it for this. The most common bottom is M111 which is followed by Bud 118. If you’re in zone 5b as your profile states both M111 and Bud 118 would be cold hardy.

Another option would be just to buy G30 which Raintree has and not do a interstem. G30 will produce a semi-dwarf sized tree.

I’m here in 5A Maine and M111 works great.

Raintree is having a sale on rootstock. I saw MM111 & EMLA 26 Apple Roostock](https://naz.soundestlink.com/link/60592f21632e030012be3b3f/60592f07b1b5330b750873a3/5e877b331215fa2ea169f1b3?signature=b5724924322a6e41183dcd2ef86caf06ffdf6fc0c4278dc20871221e5ddb9a4c)
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EMLA 26 Apple rootstock

Thanks Maureen. Their search is remarkably bad - I went there yesterday and searched M111 and 111, didn’t see those roots. I should have searched MM111… I will order some.

I clipped some B9 and 935 twigs out of my garden bed yesterday to make the interstems. Holly said he’d send me some interesting varieties from his beautiful back fence espalier down in Somerville. I’ll definitely be putting the wraps on earlier in the fall in the future!

I know you were looking for Lars Andersen peach in the past and I’m sorry I didn’t have one for you; did you ever find it?

Thanks,
BP