Common Name: Kowhai

General Information

Sophora tetraptera is a semi-deciduous to evergreen shrub or small tree growing from 4 - 12 metres tall. The short bole can be 15 - 60cm in diameter[].
The tree is harvested from the wild for local use as a medicine and source of materials. The wood is of good quality and is sometimes harvested commercially. The plant is often grown as an ornamental, valued for its large, showy flowers and foliage - there are several named varieties[].

Known Hazards

The plant contains cytosine, which resembles nicotine and is similarly toxic[].
The wood is poisonous. Two persons became very ill after eating food with a spoon made from the wood of this tree[].

Botanical References

, ,

Range

New Zealand (North Island)

Habitat

Streamsides, forest margins and lowland[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	8.00 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Sophora tetraptera is not very cold hardy, tolerating short periods with temperatures down to about -10°c when it is fully dormant[], Mature plants, with a woody framework, are considerably hardier than young plants, which can often be killed even in fairly mild winters[].
Succeeds in a well-drained moderately fertile soil in full sun[]. Requires a warm sheltered position[].
Plants are of slow to moderate growth[].
In good summers plants can set seed abundantly in cultivation[].
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[].

Edible Uses

None known

Medicinal

The bark is purgative. An infusion is drunk as a treatment for internal pains, colds and sore throats[].
The bark is boiled with mānuka (Leptospermum scoparium), poured over woodash, and then rubbed onto infected areas in order to treat diseased skin and dandruff. A lotion is applied locally to pains in the back and side[]. A poultice made from the bark is used to dress wounds, treat skin diseases, bruises etc[]. The bark is soaked in water, pounded to soften it, then applied as a pack on broken limbs[].

The inner bark isused by bushmen as a poultice for treating sprains, etc[]. A lotion made from the inner bark is applied locally as a treatment for scabies[].

A juice made from the central core of the root is taken internally as a treatment for gonorrhoea[].

The leaves are boiled and applied as a pack for treating broken limbs[].

Other Uses

A yellow dye is obtained from the plant[]. Part not specified.

The flowers are used as an ingredient in commercial cosmetic preparations as a skin conditioner[].

The wood is highly durable. It is used for cabinetmaking. millwright's work etc. It is considered to be a valuable wood for fencing, and was traditionally to make axe handles, particularly the heavier ones[].

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

Propagation

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, mid summer in a frame[].
Air-layering[].