Clianthus

If one had to choose New Zealand’s most spectacular flowering plant, the kakabeak (or kowhai-ngutu-kaka) would certainly be one of the leading candidates. In recent times, the large, bright red flowers that are borne by the two species of Clianthus have taken on additional poignancy, as emblems of the plight of New Zealand’s threatened flora.

Clianthus puniceus clings to existence within nature, with the survival of just one plant on an island in the Kaipara Harbour, whilst Clianthus maximus is represented by fewer than 200 plants in the wild, after a spectacular decline within recent years. As with the now-popular Three Kings islands climber, Tecomanthe speciosa, cultivation beckons as being an essential tool in the conservation of both species of kakabeak.

Like many other members of the pea family, Fabaceae, kakabeak are associated with disturbed and marginal habitats, such as slipfaces or cliffs – where their long stems frequently arch over and down to the ground (often layering into the soil, as shown in one of the images below). They have also been historically associated with sites of pre-European Māori habitation, leading to the hypothesis that continual cultivation by Māori has played a significant role in the survival of the species thus far.

Although they grow vigorously within cultivation, Clianthus suffer from a range of threats within the wild and gardens. Snails (the scourge of many of our threatened species) can ravage plants, as do leaf-miners and other insects. Browsing animals are a serious threat within nature, as is drought.

Our experience of these species is that in many cases, they are best treated as comparatively short-lived ornamentals (3 to 4 years) that are regularly replenished. In order to include Clianthus within a more enduring role in plantings, we continually experiment with growing them in different aspects, especially those that resemble the exposed shrubland habitats within which they occur in the wild (such as the slip face on the East Coast, pictured below, left).

One theory that we apply to the cultivation of this species is that a degree of resistance within an environment, such as exposure to wind (or their placement on extreme slopes), can also serve to inhibit some of the organisms that threaten them (whether insects or mammals). This certainly works for discouraging attack by various organisms on other native species. Another manner of encouraging a healthy balance in the growing environment of Clianthus is to create plantings that provide habitat for the kinds of small birds that predate upon caterpillars (such as those of the kōwhai moth) that can infest kakabeak.

Although we are initially including an account of C. maximus within this plant profile (purely due to the fact that we have suitable images of that species), it is important to point out that it is critical (from a conservation perspective) that both species receive the attentions of gardeners and landscapers. C. maximus has become more fashionable within recent years, and as a result C. puniceus has declined in popularity. It should be remembered that both species are of equal cultural and botanical importance, and furthermore that some of the variations in flower colour (extending to pink and cream forms) within the genus are manifested within C. puniceus.

Within conservation, the tenure of some of our threatened species is largely attributable to the efforts of certain individuals. On the East Coast/Tairāwhiti, Graeme Atkins (pictured above) has occupied such a role for over two decades, whether by direct actions or as a catalyst for introducing others to the process of protecting species like kakabeak, Dactylanthus taylorii, native mistletoes, and many other rare plants of that region. There is no doubt in my mind that without Graeme’s influence, kakabeak would be in a considerably more perilous state within the wild.

Kakabeak was discovered to Western science by Joseph Banks and Daniel Solander, at Uawa (Tolaga Bay), on Captain Cook’s first voyage to New Zealand in 1769.

The figure of William Colenso is both significant and controversial within New Zealand botany (and indeed he is a notable character within New Zealand’s social history). This remarkable man was a missionary in 19th Century New Zealand and a botanist of some note, who regularly corresponded with Joseph Dalton Hooker (then Director of Kew Gardens, and author of the first authoritative flora of New Zealand, ‘Handbook of the New Zealand Flora’).

Within taxonomy, various botanists are colloquially termed ‘lumpers’ or ‘splitters’, based on their willingness to acknowledge various forms of plants as being distinct species. Colenso’s instincts were that of the latter, and he was sometimes considered overly keen to recognise new botanical entities¹. The apparent differences between various forms of Clianthus led Colenso to assert two forms of the genus to be distinct². However, this was not officially recognised at species rank until Peter Heenan reappraised the genus in 2000.

So, in short, Colenso – who has at times been derided as too quick to proclaim taxa as being distinct – was right in this case.

Clianthus maximus now represents the majority of kakabeak left in the wild. It is found in eastern regions of the North Island, where it occupies successional habitats. The species name ‘maximus‘ obviously refers to large size; not however, as one might expect, an appreciable size difference in the flowers, but rather within the leaves. In addition to being larger, the leaves of C. maximus are glossier. The colour of the flowers is considered to be a slightly darker red than C. puniceus.

C. maximus can reach up to 5m within nature, but dimensions of 2m are more usual within gardens. It has a vigorous, arching growth form, and responds well to hard pruning within gardens.