Weeds and Natives

Forest and Bird, Issue 308, 1 May 2003, Page 3

Weeds and Natives

Pakuranga,

Auckland

—SCOTT MACARTHUR

I often read in this magazine of examples of farmland reverting to scrub and eventually bush. In Auckland wetland areas are readily re-colonised by mangroves once pollution is cleaned up. It is for this reason I am puzzled why pollen and seeds from our trees in the cities don’t re-colonise open spaces — why are intensive plantings by people required? What breaks the reproductive

cycle of our plants in the cities?

Essentially weeds, which usually smother the infant natives. Auckland has more than 360 invasive plants and is said to get a potentially serious new one, from overseas, every year. These more-aggressive introduced plants quickly colonise bare places, eventually creating a shrub forest of exotic species such as wild ginger, wandering willie, kikuyu grass, blackberry and gorse, moth plant, convolvulus, Japanese honeysuckle, pampas grass, castor oil plant, tobacco weed, wattles and privets. Restoration involves planting and weeding native species to give them a chance against the faster-growing weed species. Once established native areas still need an occasional helping

hand from volunteers and parks staff to keep the weeds down.