clings to dry eastern limestone cliffs

Size
Height: 1–2 m, Spread: 1–2 m, shrubby multi-stemmed
Lifespan
50–80 years
Diet
Not applicable (shrub). Photosynthetic.
Habitat
Dry, rocky sites, river terraces, coastal cliffs and open scrub. Prefers well-drained, often poor soils with full sun. Tolerates extreme drought, wind and frost. Often found on limestone and other base-rich rocks.
Range
Eastern South Island from Marlborough to Otago. Most common in dry, eastern areas. Restricted to the South Island. Endemic to New Zealand.
Endemism
Endemic
Main Threats
Habitat loss from land clearance is the primary threat. Browsing by introduced possums, rabbits and livestock. Climate change affecting dryland habitats. No significant pest or disease issues.
Population
Populations have declined due to habitat loss and browsing. The species is listed as At Risk – Declining by NZPCN. It is threatened by ongoing habitat loss and browsing by introduced animals.
Conservation Status
At Risk - Declining
Human Risk
poisonous
Handling Note
all parts contain cytisine alkaloids, toxic to humans and livestock
Conservation Note
Endemic shrub with fragmented populations; threatened by habitat loss and browsing by introduced mammals.
Assessment
NZTCS Vascular Plants (2023)
Te Ao Māori
In Māori tradition, this small kōwhai was less well known than the larger tree kōwhai due to its restricted range. It was valued for its hard, durable wood. Used for making small tools and weapons. The flowers were a sign of spring. The tree was also known as kōwhai. The same name used for all species of Sophora in New Zealand. Its divaricating form was noted as a unique adaptation.
It is not a tree. It is a shrub that never grows up. Prostrate kōwhai is the smallest kōwhai species. It retains its shrubby, divaricating (tangled) form throughout its life. It has small, light green leaves composed of many tiny leaflets. The bright yellow, hanging flowers appear in spring. Unlike other kōwhai species, it often grows as a low, spreading shrub rather than a tree. It reaches only 1 to 2 metres in height. A kōwhai that stays low. The divaricating growth form is a dense tangle of interlacing branches. This structure protects the plant from browsing by moa (now extinct) and other animals. The small leaves are hidden among the branches. This makes it difficult for browsers to reach them. This adaptation evolved in response to browsing pressure from moa. These were large, flightless birds that lived in New Zealand until about 500 years ago. A defence against a ghost. The flowers are typical of kōwhai. Bright yellow and hanging in clusters. They appear in spring, often before the new leaves emerge. The flowers are pollinated by birds, particularly tūī and bellbirds. The seeds are contained in dry pods that split open when ripe. A tree that blooms before it leafs. The species is restricted to dry, rocky areas of the eastern South Island. It grows on limestone outcrops, river terraces, and coastal cliffs. Often in sites that are too dry for other shrubs. It is tolerant of extreme conditions, including drought, wind, and frost. A tree that lives where others cannot. Prostrate kōwhai is used in horticulture as an ornamental shrub. Its tangled form and bright flowers make it a striking addition to dry gardens. It is hardy and requires little maintenance once established. The limestone outcrop is dry. The kōwhai sprawls. Tangled branches low to the ground. Yellow flowers bright against the grey rock. The moa are gone. The defence remains. Evolution rarely revises the draft. Populations have declined due to habitat loss and browsing. The species is listed as At Risk – Declining by NZPCN. It is threatened by ongoing habitat loss and browsing by introduced animals. Browsing by introduced possums, rabbits and livestock is a threat. Climate change affecting dryland habitats is also a factor.