A sound/barrier can help to reduce the road noise in the garden, from the nearby Circular Road, which is a modest disturbance to the ambiance and may pose a deterrent to potential hummingbird visitors.
Much more green than red (a color more eye-catching to hummingbirds) in the garden as the garden and its immediate surrounding are dominated by herbaceous perennials, particularly Heliconia latispatha.
The Heloconia latispatha dominance also contributes to the sense of a single layered garden rather than a multilayered one.
A trellis, along the southern fence, with some nutritious flowering vines would contribute to a layered garden effect.
Inclusion of annuals with shorter life cycles would complement the perennials bloom cycle; these planted in bunches can take advantage of hummingbirds attraction to broad strokes of colour.
Areas of natural shade, within 20-30 feet of the core garden, with perches would help to entice the hummingbirds to linger.
Hummingbirds like to take baths and play with water, so, the garden would be enhanced with a shallow bird bath and mister/sprinkler system.
Signage detailing visiting hummingbirds and plant species can be an advantage to the garden experience.