Linked from
The 7 pages that link to Topiary, each with the reason it gives.
HedgeBroader topic: Formal hedges can be shaped into geometric forms through sustained clipping.
French formal gardenRelated: Clipped plant forms reinforce the garden’s geometric vocabulary.
HollyRelated: Some holly species tolerate clipping into formal shapes.
Cupressus sempervirensRelated: Cypress trees can be clipped into formal shapes in gardens.
Ilex aquifoliumRelated: Holly tolerates clipping and can be shaped into formal garden forms.