Back when horticulture was still respected, a very long time ago, dense shrubbery with finely textured foliage, such as Japanese boxwood, could be purchased already shorn into cubes that only needed to be installed in a closely set row to become an ‘instant hedge’. For some small hedges composed of small plants that recovered efficiently from transplant, it actually worked reasonably well, even if they did not look so great at first. It also worked for a few larger shrubs that happened to transplant very easily, such as glossy privet. Tall arborvitaes happen to work exceptionally well as instant hedges, although the best spacing for them leaves temporary gaps in between.
However, most of the best of the bigger shrubbery should not be planted as instant hedges. The taller specie of Pittosporum get too distressed from transplants when mature, so should instead be planted while small, and allowed to grow…