branches on its upper side trained to a right angle from the main stem. U double and other U shaped espalier is just another way of referring to a double vertical cordon. Plant selection, installation, and maintenance Espalier plants on solid walls are usually installed from the base of that wall, to allow space below ground for roots to grow in all directions as well as space above ground for good air circulation and pest control. Supports for wire guides, which are generally necessary to train an espalier into a design, are installed first, directly into a wall constructed of suitable material. Masonry walls are ideal for placing U-bolts, eye bolts, or eye screws, anchored with either plastic plugs or expandable lead shields, directly into the mortar joints. Wooden walls may be better fitted with galvanized nipples, using turnbuckles for adjustment of the wire tautness. Suitable, established and healthy plants, three to four feet tall and perhaps in three-gallon containers, are available from most nurseries. Some may even have trellises already installed. These plants could also be good candidates for espalier treatment if their form is similar to the intended design, as they frequently have already been pruned into a flattened overall plant shape. All that is required for such specimens is transplanting. Unpruned plants benefit from being allowed to become well established following transplant, before pruning them gradually into their flattened profile and training them as designed. Any major pruning needed is generally accomplished either while the plant is dormant or, for flowering plants, during the proper season for pruning that species. Bending and training of the limbs that will remain in the design is done during the progression of the summer season, when they are most flexible. Related tree shaping practices Bonsai: A small tree shaped to mimic the form of real life trees Grafting: A horticultural technique of joining two or more plants together Pleaching: Way of creating a hedge with plants for stock control Topiary: The clipping of foliage of perennial plants into clearly defined shapes Tree Shaping: Creating with living trees structures and art See also Fruit tree forms Shaping fruit trees mainly to encourage fruit production References External links Espaliers: University of Florida Extension (7-page PDF guide) Growing Flat Trees - Espalier Horticulture Viticulture