So I have been mostly quiet about the espalier since we started on this retaining wall/pool reno project, but I thought I would make mention of it.
A few folks have asked about how an espalier can grow fruit when you keep cutting its branches off, others are wondering how a tree can grow despite the stresses of constantly cutting it back, and a few think its downright unnattural to grow a treet to a shape like a belgian fence.
How an Espaliered apple tree bears fruit, despite being cut back so much...Many fruit trees (most, actually) are referred to as "tip-bearing". These trees grow their fruit out on the ends of branches, where the sun will ripen the fruit and it will far as far from the trunk as possible in the hopes of the fruit spreading and growing new trees. If you grow a tip bearing fruit tree, the will do well in most applications, but not in an espalier. In an espalier you would constantly be cutting off the tips of branches that bear the fruit, and so, you would never harvest an apple (or pear, or whatever).
By some quirk of genetics, some varieties of trees are not tip bearing. For whatever reason, nature developed these trees to develop fruit buds along the branches at random spots. These trees are referred to as "spur bearing." A spur bearing tree will do very well in an espalier since you won't be cutting off the flower buds, and since the exposed nature of the tree will allow the fruit to see sunlight. In fact, a spur bearing tree grown in an espalier is supposed to be more productive than a spur bearing tree grown in its natural form, due to the ability of sunlight to reach all of the tree. Crazy, eh!
Why an Espalier survives despite constant pruning...If you cut back a plant every time it grows, you would expect it to up and die, yet an espalier needs to be pruned a lot in order to maintain its form. How does that work? Well, first of all, an espalier should be grown on dwarf or semi-dwarf rootstock. This is important because it limits the rate and vigour of new growth on the tree. Since th erate of new growth is slower, it means the tree can reserve energy despite being trimmed every few months. Secondly, the espalier can be trimmed pretty regularly without cutting off every new branch. The process should involve a balance of maintaining the tree's health, and keeping its form. The numbers I have seen have suggested pruning every 6 weeks or so, and a bit of a cleanup in early spring to keep things on track. Being that this is our first growing season with the trees, I am not an authority on this.
So far this spring we have about 6" of new growth on the trees that survived the winter. We seem to have lost all the Russetts we planted - including 2 new ones we just got this spring.
But its SO unnatural to weave a tree into a fence!!I agree, it is kinda freaky looking until you get used to the idea of an espalier. Our back fence garden is currently full of our rescues from the retaining wall garden though, and as those fill in around th ebases of the trees, I can see the shape of this garden taking form, and you know what, it doesn't look any more unnatural than a boxwood hedge, or a trimmed yew, or any other topiary.
I look forward to seeing the apple blossoms in a few years, alongside some tulips and early Iris, and whatever else I can get to bloom in the spring!
The next espalier update shows some growing quirks and a mystery plant! Here's the link!