The numbers are sobering: the north coast region of New South Wales holds seventeen of the twenty most endangered plant species in the entire state. Concentrating that much fragility in one corner of the country gives this garden an unusual mandate. It is not only somewhere pleasant to walk; it is a refuge, a place that deliberately grows the plants that are vanishing from the wild around it. Among them is the swamp orchid, Phaius australis, itself among the most endangered plants in the state, holding on in a managed bed where it can be watched and protected. Walking the Rare and Endangered section, you are looking at a living list of species that might not otherwise survive the century. The garden does the unglamorous work of keeping them alive, one specimen at a time, against the slow attrition of clearing and climate.

Roughly half the garden is not planted at all. It is the original vegetation of the site, native coastal forest and mangrove left to be itself, threaded with discovery walks and boardwalks. The mangroves are the surprise. Their pale, knotted roots rise from the tidal mud, and a boardwalk runs out over them so you can stand in the middle of an ecosystem most people only glimpse from a car window. Mangroves are nurseries for fish, filters for the water, and buffers against storm surge, and here they are close enough to read the labels. The contrast is the point: a few steps separate manicured display beds from genuine wild estuary. You move from a garden somebody designed to a forest nobody did, and back again, without leaving the block.

In June 2022 a new glasshouse opened, its tropical house held at around 32 degrees for orchids, bromeliads, anthuriums and taro, with a shade house alongside for ferns. Step inside on a cool morning and the air turns thick and warm and green. Elsewhere the garden gathers plants by climate rather than country: eastern Australian natives from heathland and coastal New South Wales, and an exotic collection drawn from regions roughly thirty degrees north or south of the equator, the same latitude band that gives Coffs its mild, humid climate. There is a Japanese friendship garden too, built with advice from gardeners in Sasebo, Coffs Harbour's sister city, where a red bridge arches over a still lake. The rainforest plot, planted back in 1987, has matured into some 350 species of canopy and understorey.

This is a garden built for lingering. The Leaf and Bean cafe sits by the entrance lawn, and grassy clearings open between the beds for a picnic or simply a long sit in the shade. Paths are sealed and wheelchair-accessible, and the sensory garden near the entrance is planted for fragrance, a bed of aromatic plants meant to be smelled as much as seen. The genius of the place is its layering. In an hour you can pass a flowering tropical orchid, a stand of endangered rainforest trees found almost nowhere else, a tidal mangrove forest, and a Japanese pond, then sit with a coffee while lorikeets argue overhead. For free, a kilometre from a city centre, it is an unreasonable amount of world to fit on twenty hectares.