Topiary is an art of training plants into different ornamental shapes like birds, animals, domes, etcTopiary is the horticultural art of clipping and training shrubs or trees into ornamental shapes and sculptures. A good topiary plant must be amenable for repeated pruning, flexible, and more vegetative growth. Best examples:For hills: Cupressus macrocarpa, Pinus patulaFor plains: Casuarina sp. , Bougainvillea sp, Clerodendra sp. , Additional InformationPergola is an outdoor garden feature forming a shaded walkway, passageway, or sitting area of vertical posts or pillars. Pergolas are designed to add shade to the backyard or in the garden passage.