Stepover Apple Trees: Winter Pruning, Year Three
For background info, please see:
Stepover Apple Trees: Winter Pruning, Year One
Stepover Apple Trees: Winter Pruning, Year Two
I’m growing three stepover apple trees on our main allotment plot and, instead of following the standard advice in most of the fruit tree pruning manuals, I’m pruning them in the winter months when they’re dormant, rather than in summer when they’re in full growth.
2022 is the third year of this deliberately unorthodox pruning regime, and I’ve held off on posting this year’s update until blossom season, so that I could show you just how well winter-only pruning seems to be working.
First, a quick re-introduction to the trees. Two of them, it has to be said, are almost entirely unsuitable to be grown as stepover forms. One is a ‘Blenheim Orange’ on MM106 (half-standard, non-dwarfing) rootstock1For more info on different types of rootstock, have a look at this highly useful overview on orangepippintrees.co.uk. and the other is a ‘Howgate Wonder’, also on MM106. I planted them before I was properly informed as to quite how vigorous those two varieties are – both triploids, both producers of large, dual-purpose apples – and quite how unsuitable MM106 is for growing trained tree forms. A classic case of if I’d known then what I know now…
The net result has been a vertical hedge of new growth every year that has had to be cut right back in an attempt to maintain the stepover form. Wiser, more sensible heads would no doubt suggest that I cut my losses, dig out these two trees and re-plant something more stepover-suitable. Nevertheless, being a stubborn so-and-so, I’ve persevered with both of them and was rewarded last year when the ‘Howgate Wonder’ produced a pair of the largest apples I’ve ever harvested; each of them over half a kilo in weight.
The third tree is a much more sensible ‘Keswick Codlin’, on either M9 or M27 (dwarfing) rootstock, I can’t quite remember which as I lost the original label years ago. It’s much better behaved and has fruited well for the past couple of years, although last year wasn’t as good as 2020, when the conditions were particularly favourable.
Here’s what I’ve done with the three trees this year:
1. Blenheim Orange
The ‘Blenheim Orange’ put on a lot of growth last year, as it usually does, but only produced a single apple2Last year was not a good year for fruit in our neck of the woods, with a hard frost in May doing a lot of damage to the blossom on our site. Besides which, this particular tree had only been in the ground for three years at that point, so was barely reaching maturity.. Here’s another angle, showing quite how much of a hedge I had to contend with3Ridiculous, isn’t it? But, knowing how vigorous the tree is and how much regrowth is likely every year, it does allow me leeway to monitor the effects that hard pruning have on this sort of tree, which means I don’t have to experiment with the standards in the Plot #79 orchard. It’s all a valuable part of the ongoing learning process as far as I’m concerned.:
A lot of strong vertical growth there – some of it three feet or more in length, all in a single growing season – and there are a lot of horizontal branches as well, most of which are blocking access paths either side. Plenty of examples of the classic re-growth pattern as well, with multiple new stems breaking out from the buds just behind the previous year’s cut-point:
Obviously this much regrowth isn’t ideal, but it’s recoverable with some slightly aggressively hard pruning. Here’s the same re-growth section after I’d cut it back:
As you can see, I’ve cut two of the stems right back to the collar – the ring of wrinkled-looking tissue at the base of each stem – which will help promote rapid healing and the growth of the sort of healthy scar tissue you can see in the centre of the photo, where last year’s pruning cut has healed over perfectly. The hollow in the centre is perfectly normal; the tree develops scar tissue over the outer edges of the stem to seal off the cambium tissue – the water, nutrient and sap-transporting outer section – but not the centre of the stem, which is mostly woody tissue and not so prone to rot or infection.
The other two stems have been left as stubs, cut just above an outward-facing bud to direct any regrowth outwards and hopefully avoid too many crossing branches. Having said that, I’m hoping that the dormant buds around the base of the stems will break into fruiting buds, helping to kick-start a new section of fruiting spurs4Although knowing the vigour of this particular tree, it’s more likely that I’ll be cutting back another three feet of new stem next year….
The rest of the tree was hard-pruned in the same manner, with badly-placed or excessive stems removed completely, and anything with the potential to (hopefully) develop into a fruiting spur cut back to a stub. I also left one or two examples of long brindille shoots that had grown out from last year’s bourse sections:
The bourse is the technical term for the ‘knob’ at the base of the long shoot (at the top of the photo, coming off the main branch). A bourse forms behind a growing apple, or cluster of apples; an anchor-point for the developing fruit. A fully-formed bourse also contains new buds that will sometimes produce fruit buds, blossom, and then a subsequent second bourse the following year, which is how strong bourse-on-bourse spur networks develop.
Alternatively, the bourse might produce a stem known as a brindille. According to some of the pomology theory I’ve read, a long brindille (over two inches) will usually produce a fruiting bud, whereas a shorter brindille (one to two inches) will often produce vegetative re-growth instead; new extension stems. True to the theory, here’s the same bourse and long brindille on April 22nd:
Beautiful, isn’t it? It’s worth bearing in mind that if I’d followed the standard summer pruning advice – which tends to be to cut back all new growth to three buds out from the base in order to encourage fruiting and/or spur formation – I’d have trimmed that brindille shoot and removed the fruit buds at the tip. Instead, I’ll now be able to let that blossom cluster develop into fruitlets, thin it to a single apple later in the year, and when that apple grows it should bend the stem downwards, encouraging the development of more fruiting buds back towards the bourse as that section of wood matures. I should then be able to trim back the stem next winter, leaving a section of fruiting wood for next year: a ready-made fruiting spur, without the extra year or two’s wait5I’ve been planning a blog post or three on the science of summer pruning for a while now, but probably won’t find time to write anything up until next winter. New full-time job just started, allotment season hitting its stride, lots to do in the garden… research will have to take a back seat again until the end of the year..
I’ll see if I can track that stem and blossom cluster through the year, to see how it develops. In the meantime, here’s the tree as I left it, post-pruning, back in January:
Not the easiest photo to study in detail (although you should be able to enlarge it by clicking on it), but hopefully you can see I’ve taken that mass of regrowth completely back, either flush to the two main branches or back to short stubs, which I hope will develop into fruiting spurs:
Here’s part of the right-hand section of the tree, with blossom just starting to open, on April 17th:
Assuming the blossom is successfully pollinated and we don’t suffer a late frost like we did last year, I’ll need to thin out each fruitlet cluster down to a single fruit, some time in May or June.
I’m also experimenting with allowing the leading stem at the end of the two horizontal branches to continue to grow. I’ll be tying them in to stout canes at either end of the tree and encouraging them to develop vertically. I’m vaguely hoping that this will help to focus some of the vegetative regrowth into these upright stems, which I can then prune back to a suitable height next year. Alternatively, I might just end up with two more sections of hedge at either end of the tree and be forced to trim them right back to the original horizontals. It’s another try-it-and-see experiment, which might work, or might not. Time will tell.
2. ‘Howgate Wonder’
The similarly-vigorous ‘Howgate Wonder’ also put on a significant amount of growth and, as already mentioned, produced two enormous apples (pictured at the top of this post). Here’s the tree before pruning in January:
It’s not quite so hedge-like as the ‘Blenheim Orange’ but again, that MM106 rootstock had fuelled a lot of regrowth, all of which had to be removed. The principles and procedure were the same: take everything back either to the point of origin, with a cut just above the collar; or leave a stub, with a cut just above an outward-facing bud, if it looked as though it might have a chance of developing a fruiting spur in future seasons.
Here’s the end result (again, click the pic for a larger version):
And here’s a close-up of one of the sections of fruiting wood, with potential fruit buds6At this stage they’re only ever potential fruit buds. If conditions aren’t right at blossom time – the wrong temperature, insufficient water or nutrients, or if there were too few chill hours the preceding winter to initiate bud development – then an individual bud could easily remain dormant for another season, or develop into a vegetative stem instead. hopefully ready to break and bloom:
I look forward to seeing whether this tree produces enormous apples again this season, or whether it spreads its energy more evenly between these developing blossom clusters:
3. ‘Keswick Codlin
Finally, having said that this ‘Keswick Codlin’ on dwarfing rootstock is much better behaved than its fellow stepovers, it seems that it still put on plenty of regrowth last year:
This tree has been fruiting well for the past two years – dwarfing rootstocks tend to encourage early fruiting – although 2021’s crop was smaller than 2020’s, as was common across our site.
Again, the pruning plan here was simply to cut back the lengthy stems to either the collar or to leave a stub. Here are before and after pruning pics of a particularly crowded section of growth that’s placed just above the main stem:
And again, I left a brindille or two but cut everything else back either to just above the collar, or to a stub. I seem to have neglected to take an ‘after’ pic of the tree back in January, but here it is on April 17th, cloaked in blossom and – with luck and good weather – ready to produce a bumper crop again this year:
End Notes
So there we have it. The winter-only pruning regime continues, and seems to be producing good results. What I’m hoping to demonstrate here is that the standard mantra that trained forms of fruit trees must be pruned in summer in order to “encourage fruiting” – which is what a lot of the pruning manuals and general gardening books will tell you – isn’t necessarily true.
I’m not saying that summer pruning is wrong – although some of the research I’ve read has highlighted a number of potential issues that the practice can cause7Again, I’m planning to explain this in much more detail in a series of blog posts, but they’ll have to wait for now… – but I hope that my three blog posts on the subject have demonstrated that summer pruning certainly isn’t necessary, even for trained trees.
In the meantime, if you have any thoughts, questions, or pointers to add, please feel free to do so, via the comments. (If it’s your first time commenting then I’m afraid the system will hold your comment until I have a chance to manually approve it, but I’ll drop you a line to let you know when it goes live.)
Footnotes
- 1For more info on different types of rootstock, have a look at this highly useful overview on orangepippintrees.co.uk ↩︎
- 2Last year was not a good year for fruit in our neck of the woods, with a hard frost in May doing a lot of damage to the blossom on our site. Besides which, this particular tree had only been in the ground for three years at that point, so was barely reaching maturity. ↩︎
- 3Ridiculous, isn’t it? But, knowing how vigorous the tree is and how much regrowth is likely every year, it does allow me leeway to monitor the effects that hard pruning have on this sort of tree, which means I don’t have to experiment with the standards in the Plot #79 orchard. It’s all a valuable part of the ongoing learning process as far as I’m concerned. ↩︎
- 4Although knowing the vigour of this particular tree, it’s more likely that I’ll be cutting back another three feet of new stem next year… ↩︎
- 5I’ve been planning a blog post or three on the science of summer pruning for a while now, but probably won’t find time to write anything up until next winter. New full-time job just started, allotment season hitting its stride, lots to do in the garden… research will have to take a back seat again until the end of the year. ↩︎
- 6At this stage they’re only ever potential fruit buds. If conditions aren’t right at blossom time – the wrong temperature, insufficient water or nutrients, or if there were too few chill hours the preceding winter to initiate bud development – then an individual bud could easily remain dormant for another season, or develop into a vegetative stem instead. ↩︎
- 7Again, I’m planning to explain this in much more detail in a series of blog posts, but they’ll have to wait for now… ↩︎
Thanks. This has reinforced some of the stuff you told me last Saturday.
Cheers Christopher, I’m very glad it was helpful.
summer pruning triggers less vigurous regrowth than winter pruning. so in addition to you current practise you could break away some new growth in summer. it will heal super fast and your winter pruning will be a bit easier.
Hi Bert –
Summer pruning is something I’ve been meaning to look into in depth for a while now. The initial reading I’ve done suggests that the restriction in regrowth vigour is due to the reduction in late-season photosynthesis due to leaf removal. But this also reduces the rate at which fruit ripens, leads to a reduction in late season secondary growth (thickening of the trunk and branches) and also reduces the tree’s capacity for nitrogen storage over winter, which then has a direct impact on successful bud development and blossom the following spring. That’s not the whole story though, it’s an awful lot more complicated than that. As I say, I really need to do more research, which I probably won’t have time for until this winter at the earliest… which will be too late for summer pruning season 😐
It would be really interesting if you grew two identical stepovers (same variety and rootstock) and summer-pruned one and winter-pruned the other. But I guess you have other things to do than carry out such experiments!
My very simplified understanding is that summer-pruning stresses the tree, and this encourages it to put more of its energy into fruiting rather than vegetative growth. (In the same way that a dwarfing rootstock stresses the tree). Is this correct?
Hi Stephen –
Yes, that would be an interesting experiment, and if I had the space and the trees then I’d definitely give it a go. I think I’d need at least half a dozen of each though, just to make even out the differences in the individual trees. Maybe one day, eh?
As for stressing the tree, I think all forms of pruning – winter, summer or whenever – are a type of stressor that will force the tree to respond in fairly, but not entirely predictable ways. But removing leaves in summer is more likely to reduce the strength of next year’s fruit buds – which will already have developed on the tree – by reducing the amount of nitrogen that the tree can store from its leaves in autumn. It’s all incredibly complex though, so many factors involved. Very difficult to pin down any simple cause-and-effect relationships.
Summer pruning for me made more vigorous shoots than winter pruning. Spring here down in Australia now, or sprummer as I call it. ( sprummer- cold nights like spring but days not quite warm enough for summer). I’m growing 2 step overs of different varieties all on M26 ( was 3, partner accidentally whipsnipped one 🙁 , but their soil differs in the amount of pampering they get. This year I’m going to get the strong vertical growths and weigh them down to the horizontal to encourage more fruiting buds and to slow down branch elongation. Will tie down later mid-late season when branches still supple and the plant will be soon allotting next years nutrient resources ( pre autumn) so hopefully won’t respond with too much vigour and send up new verticals off those tied down laterals. thoughts anyone? I agree with above- don’t remove leaves to stress plants, and most definitely not late in summer. The only time I would cut leaves is in late spring/ sprummer 2nd vegetative growth flush if I’m directing growth of one area over another. That way tree has time to respond. Not so much on stepovers though, these usually on dwarf rootstocks aren’t helped by the loss of photosynthetic power. It takes (if I remember correctly) 21 leaves to produce a bunch of grapes on vines. Not sure if anyone’s done the testing for apples (again, so many variables) but it makes you think… I’m hoping with above tie down that I don’t reduce photosynthesis too much, but the tree uses the energy in those leaves to fuel fruit buds. Maybe I’ll tie all shoots down, but on one tree I’ll prune them in late summer and the other tree I’ll prune in winter. One is a huonville crab (Australian recent variety) and has purple leaves in spring – sprummer so has photosyntheitc disadvantage over other tree.
Hi Amanda – Bending down branches is a great technique for promoting fruiting growth, and it’s recommended way back in some of the C17th and C18th fruit growing manuals, iirc, so it’s a long-practised method.
As I understand it – although I do plan to do more research on the topic and write about it in depth at a later date – it’s a case of interrupting the flow of the phytohormone Auxin from the apical bud at the tip of the shoot, which removes the effect of apical dominance and slows the extension growth tat auxin promotes. This allows the Auxin-Cytokinin balance to swing in favour of Cytokinin, which promotes bud-break. That’s the incredibly simplified version anyhow, there’s clearly lots more going on than that.
As for the number of leaves needed to make an apple, I’ve not come across a precise number, but I have read that it’s the cluster of leaves in the immediate vicinity of each fruit that provides the bulk of the photosynthates to that fruit. Resources tend to be distributed within the tree as efficiently as possible, so again, leaving leaves around fruits should result in riper fruits come harvest time. Another topic of future research there…
I did indeed weight them down, I had so many shoots I used large heavy bolts hung around large paperclips as hooks over the branches. Worked well until mid summer when those strongly shooting verticals, now tied down, sent out their own strong vertical laterals, all concentrating buckets of Auxin, nice and high up there. Most of these were concentrated in the first half of the horizontal cordon – on the trunk end not he leading tip end. I used a bonsai technique and snipped back most of the leaves of these verticals, without destroying petiole (to avoid too severe a response), attempting to redirect sap and hormone to further down tree parts. Alas, the tree said the stripped vertical growth wins out over the main horizontal trunk anyday. My insight from this is to train the main leader more vertically, to decidedly favour leading tip vigour- all those lower branches just never gave it a chance. Until it lignifies up later in the season the leading tip can be tied down as needed to balance. Going into late autumn down here in Aus, will find out in spring after late winter pruning, hopefully the first tied down shoots have indeed had enough cytokinin to stimulate expression of bud forming. Made some beautiful crab apple jelly- the huon crab has dark wine coloured flesh ( tasmanian cultivar- i suspect you can’t get this cv in UK). PS is that a ‘forget me not'(Myosotis) in your garden under trees? i introduced one plant for some pollinator flora and am now busing ripping out the thousands of seedlings. Delightful but apparently incredibly weedy here.
Hi Amanda – Thank you for the update, and for the tips re: angle of growth of the main cordon stem. I think most of mine are set at around 60° or so from the base, and they do seem to focus most of their growth in the apical tip. Or tips, once I’ve tip-pruned them to the desired height. This year they’ve been flowering fairly prolifically, after a poor year in 2023, so I’ll have a bit of thinning to do next month. Easy enough on cordons though.
And yes, that is a bit of Myosotis, which we have plenty of down on the allotment. We leave it to do its thing for ground cover and pollinator benefit, then just rip out handfuls of the stuff as and when it gets too thick, or spreads somewhere it’s not wanted. We always allow lots of it in the soft fruit section, along with carpets of self-heal (Prunella vulgaris), which helps to keep down the annual weeds.
Insightful guide! Winter pruning’s crucial for healthy trees. Loved your tips on stepover apple trees. Can’t wait to implement these strategies! Thanks.
Thank you Lachlan, much appreciated.
Yes….. the forget me nots… here it is in spring again and sure enough huge swathes of forget me nots. Well, anything that can outcompete grass (my ancient foe) is terrific in my books (and astonishing in an alarming way), and the fact that it attracts pollinators, also excellent. Forbs are better for soil biota than monocots…I’m only quietly terrified about the beast I’m allowing to colonise my land.
Anyway, sure enough those big vigourous uprights that I tied down last summer, and then tied their laterals which assumed a strongly upright stance, well I tied them down too… none of those have made flowers. I don’t think I planted trunk on enough of an angle. bugger. Still plenty of flowers further down though. I shall take solace in reading about your pomology success. I still prefer summer pruning though, for me it’s about disease control (they call this place foggy mountain). And so we grow
Hi Amanda – I’ve been doing a spot of forget-me-not control recently, just removing some of the thicker patches of seedlings from around the immediate base of trees, but allowing them to continue in areas where they aren’t likely to cause competition with cordons. We have quite a lot of selfheal (Prunella vulgaris) on the plot now as well, mostly among the fruit bushes. It’s another great pollinator lure and tends to flower a bit later in the season than the Myosotis, but again, it’s a vigorous self-seeder, so it needs to be controlled from time to time.
If you tied the laterals down last year, then the flows of auxin and cytokinins will have been re-distributed and they ought to be priming new fruit buds this year for next? I’d think this growing season would be too soon to convert the vegetative buds associated with the strong upright phase into potential fruiting buds. Next year they might be smothered in blossom. Fingers crossed!
Hi Darren, have just discovered your series on stepovers. Very interesting, thank you. Wondering if you have made any progress with a summer pruning article?
Hi Jema – Thank you very much. I’m afraid I haven’t made time for the summer pruning theory work just yet. More research is needed, which will happen once I’ve finished my series on the ‘Beefing’ Apples, which is taking… a fair bit longer than I originally anticipated. But I’ll get there, eventually! (I don’t know if you’re a member of my e-mailing list for blog post announcements, but that’s probably the best way to keep an eye on when I manage to get something posted).
Thank you so much for your article. I’m about to plant a Laxton’s Superb which I grafted on MM106 in 2023, so it really wants freeing from its pot. My intention is to create a stepover in one of our community gardens in Luton, Beds. The shape is already there. It’s not triploid, so I hope for a little less vigour than your Howgate Wonder and Blenheim Orange. I think I’ll still risk it…but I can’t say haven’t been warned!
Hi Konni – Laxton’s Superb is a really good apple, I do hope it does well for you. I suspect both my other two stepovers are on MM106 and they’re reasonably well behaved, as long as I keep on top of the winter pruning and remove pretty much all of the new season’s growth each time. Their trunks and main branches are now incredibly sturdy as well, which I suspect helps them both produce so many good apples. Whether that’s down to the rootstock choice, or the pruning regime, or some other combination of factors it’s impossible to tell, but I’m happy with the results however they came about.
Best of luck with your stepover training!
Hello Darren, thank you for the wealth of information you’ve provided hear on pruning. A number of interesting points for me to mull over as I join the club and plant my first two step overs shortly. I’m commenting as I’m quite interested in your supports setup here. I saw another post where you used large posts and tension wire but noticed here you instead use bamboo canes mounted to posts. I would be very interested to learn a bit about your thought process here. I’ve been keeping an eye on approaches used in some of my favourite gardens up north in similar windy locations to my own and haven’t come by a cane mounted one before. Super interesting! And I look forward to any thoughts or advice you might have.
Hi Christine – Welcome to the wonderful world of stepover growing! I’ll hopefully post another update this year. Not much new to report, but the trees are still going strong, and they’re shaping up really nicely now.
Support-wise, I’m moving away from post-and-wire because, it turns out, I’m not very good at installing them. Or at least, I didn’t have room for proper straining posts, so I found it impossible to maintain tension on the wires. The end result is that this year I’ll be replacing all the wires in my cordon sections with bamboo canes. The thought here being that individual canes can be replaced easily if broken, they don’t lose tension or shift position, and as long as the trees are tied to them with soft-tie, I can’t foresee much damage to the trees occurring.
I’m aiming to post about that process, so do watch this space 🙂