Sophora prostrata is a small dense Kōwhai tree endemic to the dry eastern South Island of New Zealand from Marlborough to the Waitaki Valley. It occurs naturally in grassland and rocky places, most commonly found on Banks Peninsula. A very tough plant that will tolerate cold, dry, exposed sites and coastal locations though good drainage is essential. Accordingly, it is well adapted to many of the conditions that are prevalent within urban environments; such as high winds, extreme light levels and frequent drought.
Commonly called prostrate kōwhai or dwarf kōwhai as it is a shrub that only grows to 2m tall. The shrub forms a small dense mound with tangly branches bearing leaves to 25mm long that have particularly small leaflets (4mm). Semi-deciduous. This small-growing species is distinct amongst Kōwhai, in that it maintains the divaricate growth form throughout its entire life.
Through the late winter and spring Sophora prostrata has clusters of drooping small bright yellow to orange flowers hidden amongst the divaricating branches. These are full of nectar for the native birds. Alaso attractive to bees, lizards and insects.
As it is a tough plant that attracts birds and lizards, it is suitable for restoration projects. Ideal as part of a dry woodland mix where planting will be in dry shallow soils prone to summer droughts. It is adapted to these harsh conditions. As part of the dry woodland community, it plays an important role in conditioning the soil. The soil conditioning creates a more hospitable environment for less robust species and broadleaf/podocarp forest succession. Other plants in this community include but are not limited to Discaria toumatou, Poa cita, Ozothamnus leptophyllus, Corokia cotoneaster, Melicytus alpinus and Cordyline australis.
For more information on plant communities, we recommend DOC’s publication Native Plant Communities of the Canterbury Plains.
Sophora prostrata makes a good container plant. It is one of the finest native plants for long-term cultivation in pots, as it will tolerate severe root restriction, drought and exposure to sun and wind.