Willow leaved hakea (Hakea salicifolia) is an Australian native brought to New Zealand as a fast-growing hedge plant and was probably used as wind shelter around settler’s houses. It escaped and thrived on the open ridges that had been cleared of forest, well adapted to dry infertile places. It is a problem weed in other countries too, especially South Africa and Spain, and in Australia is known as a “thug tree”.
Its winged seed is retained in a hard nut until the parent tree dies, is burnt or cut down. Then, massive germination occurs and dense groves of seedlings result. It needs high light to grow so is not found in dense forest. The infertile soil of parts of the park means that hakea will survive for a long time.
It is not wanted in the park, although the flowers do produce nectar, but it is best left so that native trees like black beech will eventually grow through it and shade it out. Alternatively, encouraging a ground-cover of lichen, moss, grasses and herbaceous plants will restrict the germination of seedlings. This means that wild animals that graze and disturb the soil should be kept away from hakea areas.