Sophora chathamica

(previously included in Sophora microphylla)

Coastal Kōwhai

ABOUT:
The flowering of kōwhai in the spring marked the time for Māori to plant kumara crops, as well as time to harvest kina and scallops. Flowering from the lower branches up indicated a warm season ahead, and flowering from the higher branches down suggested a cold, wet season to come.
Being the hardest native timber, dry kowhai wood burns hotter than coal. Coastal Kōwhai flowers earlier than other kōwhai – in September. Seeds are yellow and hard, and very poisonous if eaten.

IDENTIFY:
Vibrant yellow flowers hang in bunches, and are a favourite of nectar-loving birds.
New Zealand has 8 native kowhai species, very similar in appearance:

1.   Sophora chathamica            Coastal Kōwhai. to 20m high. Leaves to 15cm long, leaflets getting smaller toward the tip.
_____coastal across New Zealand, though largely northern half of North Island.
2.   Sophora fulvida                     Up to 10m high. Leaves to 14cm long, Up to 90 equal-sized leaflets per leaf.
_____West coast of North Island, north of Raglan.
3.   Sophora godleyi                    Godley’s Kōwhai. Up to 25m high, weeping habit. Usually a single trunk. Twigs of young plants are thin and zig-zagging.
_____Central North Island.
4.   Sophora longicarinata           Limestone Kōwhai. Usually shrubby habit, with multiple trunks, often branching from below ground.
_____Northern South Island.
5.   Sophora microphylla             Small-leaved Kōwhai. Up to 25m high. Usually a single trunk. Leaves to 5cm long. Twigs of young plants are thin and zig-zagging.
_____Across New Zealand, but scarce in North Island.
6.   Sophora molloyi                     Cook Strait Kōwhai. Up to 3m high. Shrubby habit. Leaves to 10cm long.
_____Many Cook Strait islands, and southern tip of North Island.
7.   Sophora prostrata                  Prostrate Kōwhai. Up to 2m high. Often growing tight against the rock/land because of winds. Twigs are thin and zigzagging.
_____Eastern South Island.
8.   Sophora tetraptera                 Large-leaved Kōwhai. Up to 15m high, often with thick multiple trunks and a spreading habit. Leaves are grey-green, with longer leaflets. Seeds are brown.
_____North Island. Between Cambridge and Masterton eastward.

USE:
Plant for bold spring colour and for soft texture to contrast with hard lines. Coastal revegetation and support of native bird populations is also an important benefit.

PLANT:
Likes a sunny and well-drained spot – preferring coastal ridge-lines in its natural habitat.
Avoid pruning Nov-Feb to limit borer entering the cuts.

Fine Texture

Emerging Leaves

Scores of Leaflets

Seed pods

SIMILAR TO:     
Chilean Pelu (Sophora cassioides) – aka Sophora ‘Goldilocks’. Exotic. Dark, glossy leaves, round leaflets becoming overlapped toward the leaf tip. Flowers are smaller, and open wider.
Lord Howe Kōwhai – (Sophora howinsula) – exotic. Hybrids with native species include Sophora ‘Otari Gnome’ and ‘Tui’s Gold’. Similar to Large-leaved Kōwhai, but has a large, woody swelling at the base of trunks.

ECOLOGICAL IMPORTANCE:     
Tui, waxeye and bellbirds feed on the nectar in spring. Kereru feed on the flowers and leaves. Kōwhai is one of the food sources for the caterpillars of the native Kowhai Moth. These caterpillars can at times decimate the leaves of a kōwhai tree, but generally don’t, and leave no lasting damage either way.

MORE INFO:
O2 Landscapes – Sophora
Tawapou Coastal Natives – Kōwhai
Tiritiri Matangi – Kōwhai
NZ Plant Conservation Network – Sophora chathamica