Cobb Valley

Distant valleys often exert a certain grip on the imagination, but few deliver so emphatically on their promise as Cobb Valley. Its geology shifts from limestone to serpentine and sandstones, and includes some of the oldest rocks and fossils found on this landmass.

Its long channel (carved out by successive glaciers) acts as a funnel for the kinds of cold winds that influence the headwater of major rivers in several parts of the South Island – important environments for one of our most enigmatic small trees, Pittosporum patulum (pictured below, within open beech forest adjoining the river).

At the end of a recent work trip to Golden Bay, we spent a day looking around Cobb Valley’s forests and subalpine shrublands with our former colleague, Winston Dewhirst (who now resides in Nelson).

We have a longstanding interest in Pittosporum patulum (having specified it in a significant number of South Island projects), but Logan, Winston and Liam had not yet seen it in the wild. Fortunately, they could scarcely have picked a better population to see this magnificent species for the first time, with two subadult trees providing a fine demonstration of the kinds of places in which this nationally endangered tree would have previously been more prevalent.

These ethereal beech woodlands (characterised by an understorey of fine-leaved shrubs and narrow, upright trees) also contained good numbers of a particularly elegant lancewood species that we rarely see – Pseudopanax linearis. This species (pictured below, right) occurs naturally within high-rainfall habitats along the western flank of the South Island, and exhibits a compact form and attractive foliage – with the yellowish-cream midrib providing definition to the sharp-tipped leaves.

Having seen Pittosporum patulum in other populations (including its stronghold at Temple Stream), I had my sights set on a subtle native grass that I had never seen in the wild – Stenostachys gracilis. Logan was equally excited to see this low-spreading, glaucous grass – having searched for it unsuccessfully in a Central North Island frost flat.

We don’t expect this fine-leaved grass to take landscape architecture by storm any time soon, but we do have a soft spot for the cast of little-known characters that would have previously played a greater role in environments such as this riverine beech forest.