This technique of representing well known nature elements inside the garden (mountains, rivers, islands) is called shukukei, meaning reduced-scale landscape and was originally used in the gardens of the Edo period lords.
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 24mm
Aperture: F/6.3
Shutter Speed: 1/1250s
ISO Sensitivity: ISO 320