Sophora tetraptera

Sophora tetraptera is a shrub or tree from New Zealand’s North Island. It belongs to Fabaceae, the pea family. Common names include kowhai, New Zealand laburnum, and winged-podded sophora. In the wild, it grows beside streams and along forest edges. It also grows in lowland sites. Its native range extends south from East Cape. Kew places it in the subtropical climate group.

In gardens, it forms a large shrub with spreading branches. It reaches about 13–26 feet [4–8 metres] tall. Its spread is about 8–13 feet [2.5–4 metres]. Plants take 10–20 years to reach their full size. The bushy crown keeps some of its leaves through winter. Its pinnate leaves contain many small, oval leaflets. Each whole leaf can reach about 0.5 feet [0.15 metres] long. These divided leaves give the crown a fine texture.

Yellow flowers hang in clusters in late spring. Each bloom looks tubular and reaches about 0.16 feet [0.05 metres] long. The hanging flowers stand out against the divided leaves. The RHS lists this species for cottage and informal gardens. It also suits city gardens, courtyards, and coastal sites. Other suggested settings include beds, flower borders, and wall-side borders. Plants For A Future lists it for sunny woodland edges.

Grow it in full sun with shelter from exposure. The RHS favours a south-facing site and soil that drains well. Suitable soils include chalk, loam, and sand. It accepts acid, neutral, and alkaline conditions. The supplied moisture guidance spans dry to moist soil. The RHS rates it H4 for UK hardiness. Plants For A Future gives USDA zones 7–10. Sow ripe seed in pots in a cold frame. Another option is semi-ripe cuttings in summer or autumn. These cuttings need heat beneath them.

Few pests trouble this plant, according to the RHS. Honey fungus can occur, though the source calls it rare. Do not eat any part of the plant. It contains cytisine, a toxic compound with effects like nicotine. The RHS also warns that eating it can harm dogs. Plants For A Future records no food or medicinal uses. It fixes nitrogen and supplies strong, dense, lasting wood. Recorded wood uses include bearings, turned objects, cabinets, and decorative work.