An espalier can bring any plain wall or fence to life by adding color, texture, smell  and many other elements. You may be asking what exactly is an espalier? It is a French word that derives from the Italian spalliera meaning to rest on (more specifically a shoulder: spalla). First introduce in the Roman times and later mastered in the European Middle Ages, espaliers were a way of planting fruit trees and berry-bearing shrubs in limited spaces (small courtyards) because they are trained to grow vertically along flat surfaces.
They have since become a way to decorate walls using intricate designs that range from fan shapes to the detailed Belgian arch. Today espaliers can be made from a wider selection of plants from Trumpet Vines and Camellias to even some varieties of Magnolias! But you can never go wrong with a traditional fruit tree like a lemon or orange tree.
So if you have limited space in your yard or want to cover up a plain looking wall, espaliers are the way to go! Many trees or shrubs can to grow against a flat vertical surface.
Here are some of our recommendations for plants that are sold as espaliers:

Bougainvillea ‘California Gold’ – California Gold Bougainvillea
Camellia sasanqua ‘Chansonette’ – Chansonette Camellia
Calliandra haematocephala – Red Powder Puff
Distictis buccinatoria – Blood Red Trumpet Vine
  Magnolia grandiflora ‘Little Gem’ – Little Gem Southern Magnolia1
Fruit Tree Apple ‘Fuji’
Citrus X ‘Improved Meyer’

1picture by Erica Glasner from HGTV