Erosion gardens

February 29, 2016

Conditions have to get really tough for gorse to play well with others. This thought crossed my mind as I walked past wind-battered plant communities on the eroding coastal cliffs between Bethells Beach and Muriwai. One of the friends with whom I was walking on that day referred to these raised groupings of primarily native plants as ‘erosion gardens’, for they appear to be both formed by and obstinately holding out against erosion.

These ‘erosion gardens’ take on an intriguing, wind-sculpted character, which is partially determined by the bobbling topography of the mounds, as well as the tapestry of species that make their home in this situation. Corokia cotoneaster is relatively rare in the Auckland region, but it occurs in large numbers within the shrubland that dominates the steep slopes at the highest points of this stretch of coastline (as shown below left).

Isolated specimens of C. cotoneaster also grow amongst the pasture that rolls through from adjacent farmland (such as the plant pictured below). As one walks along the clifftop track, the rolling pasture on the inland side (which has a beauty of its own) and the diverse shrubland on the seaward side stand in sharp contrast to each other. In the most inhospitable patches of the ‘erosion gardens’, Pimelea prostrata and Leucopogon fasciculatus bedeck the ground in alternating hues of pale green and blue (as one can see in the image above right).

Other plants that make up the limited range of species in the ‘erosion gardens’ include manuka, toetoe and gorse (which plays a minor role due to the exposed conditions). Elsewhere, on the return drive, a native meadow grass, Dichelachne crinita, brought a sense of movement to dry grassy roadside verges, where it formed a beautiful scene with wild carrot and dandelions.