Replanting damaged landscapes with native plants began in the 1960s when the Department of Lands and Survey restored land around hydroelectric dams on the Waikato River. The department set up a native plant nursery at Taupō and grew large volumes of hardy natives. Over time, local bodies and community groups throughout New Zealand also began planting natives to restore plant communities and to provide food and habitat for native wildlife. Revegetation groups either raise plants themselves, or commission commercial nurseries to do so. By the late 1990s there were about 300 commercial native plant nurseries in operation.
Modern revegetation work uses only locally sourced plants. Plants that have been created by breeding (cultivars and man-made hybrids) are not used because their genetic make-up is different from that of local plants. The advantage of using local plants is that they are adapted to the soils and climate of the area, and once established require very little maintenance.
Restoration projects include:
- Restoration of subalpine shrublands along the Ohakune Mountain Road, Mt Ruapehu
- Forest revegetation of islands that had been farmed: Mana, Matiu (Somes Island), Tiritiri Matangi
- Swamp revegetation, Travis wetland, Christchurch
- Restoration of sand dunes, Long Bay Regional Park, Auckland.
Native crop plants
Apart from ornamentals, few native plants have been grown commercially. New Zealand flax (Phormium tenax) was cultivated from the 1860s until the 1980s for its fibre, but plant disease and competition from other imported fibres spelt the end of the industry.
For a short period (1976–83) poroporo shrubs (Solanum laciniatum and S. aviculare) were grown in Taranaki because they contain solasodine, a plant steroid used in contraceptives. However, it proved cheaper to raise such plants in other countries or use synthetic substitutes. Poroporo is no longer cultivated in New Zealand.
The only native plant that is grown as a food crop is New Zealand spinach, or kōkihi (Tetragonia tetragonioides), a sprawling perennial herb whose stems and arrow-shaped leaves are boiled or steamed and eaten as a green vegetable. The plant was introduced to Britain in the 18th century and is grown there as an annual. Although not widely grown in New Zealand or overseas, it has the status of a specialty or novelty green.
Few native plants have been successfully grown for the cut-flower trade. However, increasingly cultivars with colourful leaves are being grown for New Zealand and overseas flower markets. Pittosporum foliage is the main export, with 1.4 million stems exported in 2003–4, mainly to Japan. Foliage of mānuka, kamahi and New Zealand flax is also popular. New Zealand exporters compete with Italian and Irish growers of New Zealand flax, Pittosporum tenuifolium and Brachyglottis greyii.