Kowhai
Sophora tetraptera

Family: Fabaceae or Leguminosae

What it is like

Sophora tetraptera is an evergreen Tree growing to 10 m (32ft) by 6 m (19ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 8. It is in leaf all year, in flower in May, and the seeds ripen from September to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. It can fix Nitrogen. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Height (m): 10

Where it is found

Streamsides, forest margins and lowland on North Island in New Zealand, from East Cape to latitude 40° 30's.

New Zealand and S. America - Chile.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Medicine

Rating: 0

Other

Rating:

Wood - compact, dense, heavy, of great strength, tough, elastic, extremely durable. Used for bearings, turnery, cabinet work, ornamental uses etc.

Wood: A list of the trees and shrubs that are noted for having useful wood.

Nitrogen Fixer: Plants that fix nitrogen in the soil

How it is grown

Succeeds in a well-drained moderately fertile soil in full sun. Requires a warm sheltered position. It grows best in the warmer areas of the country where the wood will be more readily ripened and better able to withstand winter cold. Hardy to about -10°c, it succeeds in the open in southern and south-western Britain but is best grown against a wall elsewhere. Plants are of slow to moderate growth. In good summers plants set abundant seed in this country. Plants should be container-grown and planted out whilst young, older plants do not transplant well. Plants in this genus are notably resistant to honey fungus. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby.

Propagating it: Seed - best sown as soon as it is ripe in a greenhouse. Pre-soak stored seed for 12 hours in hot (not boiling) water and sow in late winter in a greenhouse. Prick out the seedlings as soon as they are large enough to handle into individual pots in the greenhouse, and grow them on for 2 years under protected conditions. Plant them out into their permanent positions in early summer of their third year. Cuttings of young shoots with a heel, July/August in a frame. Air-layering.

Best place to grow: Woodland Garden Sunny Edge;

Habit: Tree

Hardiness: 7-10

Growth: Slow

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Moist

Things to keep in mind

The plant contains cytosine, which resembles nicotine and is similarly toxic.

Its other names

Local names

Synonyms

Edwardsia grandiflora.