I'm not usually that sure about what you might call 'land art'. I tend to find myself wondering how you're going to mow an inverted grass cone, and other such imagination-killing practicalities.
But in this case: to hell with the mowing conundrum. Marry land art with a sheet of water and you have absolute sculptural perfection.
The thought behind the garden was that the mound above the water represented the children who have all they need; the sunken grassy pit was those in poverty. The screens fragment the view and from only one perspective is the sphere seen, in reflection, as a perfect whole.
Oh yes - and the planting was subtle, understated and, I thought, sublime, especially against the brooding slatey greys of the (recycled plastic, though you wouldn't know it) screens.
A little planting list for the notebook:
Allium giganteum, Ammi majus, Deschampsia cespitosa "Goldschleier', Gaura lindheimeri "Whirling Butterflies', Nassella tenuissima, Stipa gigantea, Thalictrum flavum ssp. glaucum x rochebrunianum 'Elin', Verbena "Lavender Spires", Verbena bonariensis, Veronicastrum virginicum "Fascination"