Crenellated parapet pruned Euonymus japonicus 'Aureo Marginatus' with background unidentified shrub wearing a brown autumn coat.
I get the feeling that an under-gardener grew tired of endless 'cloud pruning' and shaping of shrubs into nice round shapes and decided to go for a more medieval castle look, perhaps being influenced by a computer game involving dungeons and dragons.
This Euonymus or Japanese Spindle bush has never been a favourite shrub of mine as it always tends to look a little stiff and the colour is a very harsh shade of yellow. Hey big bird canary look at me kind of thing. It also more often than not reverts back to green in places as can be seen in the left section. Maybe this is not an issue if you want to show the Aussie colours of green and gold however. Growth can also be uneven if you plant it as a proper hedge with some sections racing ahead while others sulk and fail to grow properly. I pass a hedge like this where the individual plants look like sullen lumps and have never met up properly. Otherwise it is a very cold and drought hardy shrub with few pest and disease problems.
Crenellated parapet illustration from the Dictionary of French Architecture,11th to 16th Century (1856) by Euguene Viollet-le-Duc (1814-1879)