All Apple trees fruit on spurs but each spur will last up to 15 years - the apples will grow off those spurs over and over. Espalier is a pruning method. Usually, you would choose 3 or so evenly spaced branches around the trunk to be the backbone of your tree. In Espalier, you choose the branches that grow sideways. There are a lot of commercial apple and olive growers in California using this method of pruning. They usually orient their tree rows north to south to take advantage of the sun but, as you are growing on a fence, it doesn't matter.
Is the fence solid or corral style? If its corral style, you may end up with all your fruit on the wrong side of the fence, depending upon orientation.
Espalier trees look like a ladder while regular trees look like a vase. It takes a lot of pruning to keep an apple tree producing, no matter the pruning method you choose. Normally, you would cut back every brand to just two or three spurs/buds. In Espalier, you need to develop those side branches and then cut back to two or three buds on the branchlets.
I had two best friends in California. One grew apples and one grew pecans. Pecans are easier.
Choose apple varieties that will grow well in your area (talk to the farm extension of your local college). Choose apples you personally like AND choose your trees in person so that you can see how they are branching to find the most suitable tree for your plans.
Farmers Markets are wonderful places to go fruit tree "shopping". Taste and ask what variety (if you like it).
Daisy
