A. Yes, it is. An espalier is an innovative way to soften a brick wall, a trellis or even a chain link fence. If space permits, consider using more than one tree. The Red Jewel crabapple trees on the Visitor Center are espaliered into basic Y-shapes that are then extended into a diamond pattern.
Early spring is the best time to begin your espalier. First, choose a small 3- to 4-foot whip growing on dwarf rootstock. Prune the whip back to two strong buds (this may mean you actually prune back half the whip). Rub out all buds below this cut. Plant the whip no more than 12 inches from the wall. Best results are obtained when the tree is trained against a support (such as bamboo stakes) rather than directly against the brick. Secure these stakes to the wall and tie the whip to the bamboo using soft ties. Two new shoots will begin to grow from the two buds. Train these shoots by gently pulling them apart into a V-shape and securing them to bamboo stakes.
In winter, prune these secondary branches back by half. This will create a nice flush of leaves below the cut. This last pruning will also stimulate a third pair of branches that can be trained into the diamond pattern or pruned out completely if you simply want to keep a Y-shape. Avoid heavy fertilizing, which will produce more vegetative growth and little fruiting growth.