Coprosma petriei aka Mirrorplant

Coprosma petriei is a small evergreen shrub from New Zealand. It belongs to the Rubiaceae family. It grows on both the North and South Islands. Its habitats include grassland, stream edges, rocky ground, and dry riverbeds. These sites range from lowland areas to high mountain grassland. Kew places it in subalpine or subarctic climates.

The plant forms a low, dense carpet of growth. It reaches about 0.3 feet [0.1 metres] tall. Its spread is about 1.6 feet [0.5 metres]. The foliage stays on the plant throughout the year. This low form suits ground cover and rock gardens. Plants For A Future suggests spacing plants about 0.8 feet [0.25 metres] apart. It also lists sunny woodland edges and dappled shade as garden sites.

Male and female flowers grow on separate plants. Wind carries pollen between them. Both sexes must grow together to produce seed. The species cannot fertilise itself. Its fruit can be white, blue, or sea-green. Each fruit measures about half an inch across. Plants For A Future reports seed ripening in August. It also notes that plants seldom bear fruit in Britain. The species crosses freely with some other members of its genus.

Grow it in sun or light shade, with good drainage. Moist soil suits it, though established plants have survived very dry conditions. Plants For A Future describes it as drought tolerant. Sandy and loamy soils suit it well. It accepts other soils when water drains away freely. A mildly acid to neutral soil is preferred. The source lists USDA hardiness zones 6–9. It also reports outdoor success in British rock gardens. Young plants need cold protection during their first winter outdoors.

The fruit can be eaten raw or cooked. It tastes sweet but has little flavour. Roasted seeds can serve as a coffee substitute. The wood yields a yellow dye without a mordant. Plants For A Future lists no known hazards or medicinal uses. It reports no weed potential. Seed propagation can be slow, taking more than a year. Stored seed can be sown in spring under cold-frame cover. Autumn cuttings offer another way to raise plants. Seedlings should spend their first winter under glass before planting out.