Don’t look down ….

November 2, 2013

One of my enduring memories of this year’s Labour Weekend will be the sheer drop that we skirted on farm roads in to the Seaward Kaikouras. One of our destinations (the Chalk Range) is accessed via well constructed, yet nevertheless nervewracking, single carriageway roads fashioned from precipitous scree slopes. This was followed by a steep climb by foot to look for rare plants on this distinctive system of screes and bluffs (some of which is shown in the image below).

Over the course of the weekend, we visited other sites in north Canterbury and Marlborough, to see a variety of distinctive native plants from this part of the country. The images garnered on our trip will form the basis of a regional planting guide on the flora of Marlborough, in one of next year’s issues of Landscape Architecture NZ magazine.

At the foot of one end of the Chalk Range, an interesting wetland called ‘the Zoo’ is home to a small number of very large specimens of an endangered species of tree daisy, called Olearia hectorii. These impressive individuals show the potential of this deciduous tree for cultivation – especially when the attractive trunks and branching structure are exposed (by pruning, in the case of cultivation).

It was good to see a large number of plants over a wide age range in the surrounding area (as recruitment failure is one of the major threats to this species). Along with other species of small-leaved tree daisies from the South Island, Olearia hectorii is ecologically important as a host for several species of native moths that only occur on this group of Olearia spp.

On our way through to Marlborough, we stopped at Castle Hill and Weka Pass – two areas with distinctive limestone ecologies and plants. At Castle Hill, we observed many plants of an attractive, white-flowered forget-me-not called Myosotis colensoi, whilst at Weka Pass we located a population of a beautiful, endangered cliff dweller called Heliohebe maccaskillii.

H. maccaskillii is pictured in the images above and below. This compact species of Heliohebe is only found in a confined area in the environs of Weka Pass. Ironically, this seriously threatened species has benefitted from at least one form of human activity – the construction of railway cuttings that provided it with the fractured limestone banks that it prefers.

To a gardener’s eye, its mounded growth form bears an intriguing resemblance to the way in which various species of thyme occupy cliff habitats – although H. maccaskillii‘s flowers are much more conspicuous than those of thyme.

On the south Marlborough coastline, remnants of coastal vegetation endure on the southern end of Clifford Bay (which leads around to Cape Campbell). These form striking associations in parts, such as the mosaic of windbeaten shrubs (dominated by Coprosma propinqua) in the image below. Clematis forsteri added a delicate presence to this rugged scene, adorning the surface of the C. propinqua with its scented, cream flowers.

Marlborough’s distinctive and violent geological history (and present, as proven by recent earthquakes) was well demonstrated in physical form on the shoreline at Marfell’s Beach – where the jagged, tilted limestone shown below is the result of uplifting and folding over an extended period of time.

Throughout much of the Marlborough coastline, Heliohebe hulkeana ssp. hulkeana puts on a spectacular show in late October, in a variety of shades (from the intense lilac demonstrated below to pale, whitish-pink hues). The specimen below occupies a low-lying limestone outcrop near Ward, where it grew in the company of Pachystegia insignis (as it so often does).

Marlborough Rock Daisies (Pachystegia spp.) were on the brink of flowering over Labour Weekend. Over the entire length of the coastline (as well as inland localities), I only viewed a handful of plants on which flowers had opened, including one specimen near Ward (which is pictured below). Within one or two weeks, Marlborough will erupt with Pachystegia‘s beautiful white flowerheads.

One of the most fascinating places that we were fortunate to view was a significant natural population of the endangered Muehlenbeckia astonii, near Cape Campbell. Although it is now common in cultivation, M. astonii is only found in widely scattered populations, just one of which numbers more than a few dozen plants.

Although encouraging, much of its horticultural popularity does not offer the practical conservation value that one might expect, as the majority of plants that are propagated are cutting-grown clones of female plants (and are therefore unable to form viable populations in cultivation).

As we moved through the marram grass to look at the large mounds of M. astonii back from the shoreline, copper butterflies alighted upon their branches (which were covered in parts by native spinach, Tetragonia implexicoma). The manner in which the shadowy figures of Muehlenbeckia astonii break the tawny expanse of marram creates a spartan but beautiful landscape – one that can provide insights into the manner in which M. astonii may be employed within plantings.