Some authorities are spelling the name of this species Tetragonia tetragonioides[]. We are following the spelling in IPNI, Tropicos and GRIN[].

Common Name: New Zealand Spinach

General Information

Tetragonia tetragonoides is an annual to short-lived perennial creeping plant growing about 20 - 40cm tall and spreading to form clumps 1 metre wide or more.
The plant has been used as a vegetable since at least the 18th century AD. It is occasionally cultivated in gardens for its edible leaves, and is an excellent spinach substitute for hot dry weather conditions[].

Known Hazards

The plant contains calcium oxylate and saponins.
Perfectly alright in small quantities, leaves containing oxalic acid should not be eaten in large amounts since it can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[].
Although poisonous, saponins are poorly absorbed by the human body and so most pass through without harm. Saponins are quite bitter and can be found in many common foods such as some beans. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish[].

Botanical References

,

Range

E. Asia - Japan, Korea, southeast China, Vietnam; Australia - all States, New Zealand.

Habitat

Coastal sand dunes and stony beaches on North South and Stewart Islands of New Zealand[]. Sheltered beaches, salt marshes and arid plains in Australia[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Annual/Perennial
Height	0.30 m
Growth Rate	Fast
Cultivation Status	Cultivated, Wild

Cultivation Details

New Zealand spinach is a plant of the warm temperate zone to the tropics. It does not grow well in lowland areas of the tropics, but is cultivated at elevations above 600 metres and does best at 1,000 - 1,700 metres[, , ]. It grows best in areas where annual daytime temperatures are within the range 19 - 28°c, but can tolerate 10 - 36°c[]. The plant cannot tolerate frost[]. It prefers a mean annual rainfall in the range 900 - 1,200mm, but tolerates 700 - 3,000mm[].
Easily grown in the garden[], it prefers a light soil in a sunny position[, ] and thrives in dry soils[]. It grows best in a good rich soil[]. Prefers a pH in the range 6.5 - 7, tolerating 6 - 7.5[]. Once established, the plants are very tolerant of drought[]. Plants are very tolerant of hot, dry conditions but cannot tolerate frost[]. Although very drought tolerant, the plants produce a better quality crop if they are given some water in dry weather[].
A very reliable crop that produces a good bulk of leaves and is little troubled by pests[].
Harvesting of the terminal shoots may begin 2 - 3 months after sowing the seed and continue for several months to a few years[].
Yields per harvest can be 2.5 tonnes per hectare, equivalent to 2.5 kilos per square metre per harvest or 30 tonnes per hectare per year[].
There is at least one named variety[].

Edible Uses

Leaves and young shoot tips - raw or cooked. A spinach substitute[], the shoot tips are harvested when about 8cm long, this encourages plenty of side growth with lots more shoots to harvest[]. A delicious substitute for spinach, the very young leaves and shoots can also be eaten raw in salads[, ]. The leaves are a good source of calcium and phosphorus[]. The young leaves are best, older leaves developing an acrid taste.

Medicinal

The plant is used medicinally[].

The leaves are antiscorbutic[, ].

Whole plants showed distinct anti-ulcerogenic activity in tests. The active principles were determined as sterylglucosides and cerebrosides[].

Other Uses

None known

Propagation

Seed - sow early to mid spring in a greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and plant them out after the last expected frost[].
Seed can also be sown in situ in late spring, though this will not generally make such good plants[, ].
The seed can be slow to germinate, soaking in warm water for 24 hours prior to sowing may help[, ].