I have a Belgian fence that I started about five years now, though I ended up extending the fence and moving a few things around during that time. Some of the trees are setting fruit for the first time this year. Just for reference, I’m on the border of zone 5 and 6, with loamy sand soil. I am not super experienced, but here’s the way I set things up.
I started with scion and rootstock (mostly G41). My first trees were bench grafted, but after that I switched over to grafting to rootstock that’s been in the ground for a year, and I’ve gotten better results that way.
The Belgian fence now consists of twenty-five trees planted two feet apart, south facing but partially shaded by large maple trees (city street trees). The trees are planted in an area that I mulch annually with wood chips. They’re only about six/seven feet back from the street, which is not ideal, but we have a fairly small yard so that ended up being the best layout I could come up with. I’ve planted a border of perennials between the trees and the street (mostly irises and daisies at this point), planted daffodils along the line of trees, and a variety of herbs along the path between the trees and our house.
I set up the trellis using eight foot black locust split rails for the end posts with garden t-posts set at eight foot intervals in between them. I strung two wires on the t-posts at two feet and four feet and constructed a trellis by tying bamboo to the wires in a criss-cross pattern. (My parents have bamboo at their house so I used/am using mostly that.)
The first course of bamboo took the lattice up to a bit above the second wire. As the trees have gotten bigger, I’ve started adding a second course that will go up to a bit over six feet. Overall, the trellis is somewhat fiddly to set up, but it has lasted pretty well and has been effective for training the trees (though I do occasionally have to go back and adjust things when the “diamonds” get a little out of whack).
One useful thing about the trellis is that the bamboo lattice helps to fill things in visually until the trees grow out.
I selected and arranged the varieties in the fence with an eye to having tasty fruit, a range of flavors and harvest times, and attractive, generally healthy trees. I’ve moved things around a bit and there will probably still be some adjustments to come, but the current lineup is:
Edward VII
Court Pendu Plat
Hunt Russet
Roxbury Russet
G41 rootstock to be grafted next year
Roxbury Russet
Kidd’s Orange Red
Pitmaston Pineapple
Adam’s Pearmain
Gray Pearmain
Black Oxford
Westfield Seek No Further
Wheeler’s Golden Russet
Westfield Seek No Further
Black Oxford
American Beauty
Mother
Reine des Reinettes
Kidd’s Orange Red
Orleans Reinette
Hoople’s Antique Gold
Orleans Reinette
G 41 rootstock to be grafted next year (likely to Hunt Russet)
Cornish Aromatic
Old Nonpareil
As the list shows, I tried to balance having a nice mix of varieties with having some order in the arrangement, so you have the pairs of Black Oxford and KOR and then also the pairs of Roxbury Russet, WSNF, and Orleans Reinette. And each of the things that I doubled up on was something that I wanted to have more of. (Roxbury Russet and Orleans Reinette because those were the apples that my wife and I liked best out of the antique apples we’ve tried, KOR because it was something that should fit with my daughter’s tastes, Black Oxford because of its rep for being a good keeper, and WSNF because it’s super local for us and supposed to be an exceptional apple.)
That being said, my experience has been that even trees of the same variety planted at the same time in the same place and trained to the same trellis will not grow exactly the same. And just in general, you would have to be both more expert and more maniacal than I am to get individual trees to grow in a perfectly balanced way, much less a whole row of them. But I’m ok with that, and the overall pattern of a longish Belgian fence will cover up a lot of imperfections. (I don’t even notice the gaps where there’s just a stub of rootstock at this point unless I’m looking for them.)
One additional note: in my admittedly limited experience, information about whether trees are spur-bearing, tip-bearing, or partially tip-bearing is not entirely reliable, or perhaps more to the point, not entirely applicable when it comes to whether a variety will work for espalier, especially when it comes to older and more uncommon varieties. For example, Adam’s Pearmain, which orangepippin.com lists as partially tip-bearing, certainly does form spurs and has been one of my first varieties to flower and set fruit. (Also, different sources provide different info on these things: Keeper’s Nursery in the UK lists Adam’s Pearmain as spur-bearing and sells it in espalier forms.) So, just because you see a variety listed as partially tip-bearing doesn’t necessarily mean that it won’t work for espalier.