Tetragonia tetragonioides
(New Zealand spinach)

Preferred Common Name

• New Zealand spinach

Other Scientific Names

• Demidovia tatragonioides Pallas, Enum. Hort. Demidof 150, t. 1. 1781.
• Tatragonia cornuta Gaertner, Fruct. Sem. Pl. 2: 483. 1791.
• Tetragonia expansa Murray, Commentat. Soc. Regiae Sci. Gott. 6: 13. 1783
• Tetragonia expansa THUNB. ex MURR.
• Tetragonia halimifolia G. Foster, Fl. Ins. Austr. 39. 1786.
• Tetragonia inermis 1852. F. Mueller, Linnaea 25: 384.
• Tetragonia japonica Thunberg, Fl. Jap. 208. 1784.
• Tetragonia quadricornis Stokes, Bot. Mat. Med. 3: 127. 1812, nom. illegit.
• Tetragonia tetragonoides

International Common Names

• English: New Zealand spinach; perpetual spinach; sea spinach
• Spanish: espinaca de Nueva Zelandia; Espinacia de Nueva Zelandica; spinaca Nuevo Zelandia
• French: epinard; Epinard de la Nouvelle-Zelande; tetragon; tetragone; tetragone cornue
• Chinese: xin xi lan bo cai; yeung poh tsoi
• Portuguese: espinafre de Nova Zelandia

Local Common Names

• Chinese: summer spinach
• Russian: Novozelandskii shipinat; tetragonia shpinatnaia
• Australia: Botany Bay greens; Sydney greens; warrigal cabbage; warrigal cabbage; warrigal greens; warrigal spinach
• Brazil: espinafre da Nova Zelandia
• Croatia: Novozealandski shpinat
• Denmark: Newzealandsk spinat
• Germany: Neuseelaender Spinat; Neuseelandischer spinat
• Greece: spanaki Neas Zilandias
• Hungary: Ujzelandi paraj
• Italy: spinacio della Nouva Zelanda; Spinacio della Nouva-Zelande
• Japan: tsuruna; Tsuruna
• Netherlands: Nieuwzeelandse spinazie; Niewzeelandse Spinazie
• New Zealand: kokihi; paraihia; rengamutu; rengarenga; tutae-ika-moana
• Norway: Ny-Zealandsk spinat
• Philippines: baguio spinach
• Poland: szpinak Nowozelandzki
• Serbia: Novozelandski spanac(h)
• Slovenia: Novozelandska schpinacha
• South Africa: Nu Zeeland spinasie
• Sweden: Ny-seelaendisk spenat; Nyzeelandsk spenat
• Switzerland: neuseelander-spinat

EPPO code

• TEATE (Tetragonia tetragonioides)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Caryophyllales
•                         Family: Aizoaceae
•                             Genus: Tetragonia
•                                 Species: Tetragonia tetragonioides

A variety of latin binomials have been used for the New Zealand spinach Tetragonia tetragonioides (currently accepted). The most frequent synonym in the literature is Tetragonia expansa, and there may be as much literature referring to the latter as to the former.

From Vivrette (2004):

Stems: mat-forming, spreading to 30-140 cm. Leaves: 10-100 by 50-50 mm; petiole 10-30 mm, winged; blade pale green abaxially, dark green adaxially, midvein and lateral veins raised abaxially, ovate-rhombic to triangular, base truncate, papillate with larger papillae abaxially. Inflorescences: peduncle to 2 mm. Flowers: sometimes unisexual; calyx lobes spreading, yellow, ovate to half orbiculate, 2 mm; stamens clustered or scattered. Fruits: turbinate, 8-12 mm; horns 4-6. Seeds: smooth.

From Morris and Duretto (2009):

Annual or perennial herb, decumbent or ascending; stems to 1 m long. Leaves broadly hastate, rhomboid or lanceolate; petiole 10–45 mm long, papillose, decurrent; blade 10–80(–100?) mm long, 5–50 mm wide, dark green above, paler below with larger papillae. Flowers axillary, solitary or rarely 2 together, 8–10 mm diam.; pedicels to 5 mm long. Calyx lobes 4–5, 1 or 2 of them ovate-semiorbicular, larger than the rest, the smaller lobes ovate-triangular to lanceolate, obtuse or acute; adaxial surface yellowish, minutely papillose; abaxial surface green, papillose. Stamens 8–16, in groups alternating with the calyx lobes. Stigmas 3–8(–10?) in 2 groups, equal in number to the loculi. Fruit indehiscent, at first green, becoming dry and bony, to 13 mm long and 12 mm wide, globular or turbinate variously ridged at the summit; ridges produced into short equal or unequal horns. Seeds in 2 rows, c. 2.5 mm long, pyriform. Flowering and fruiting throughout year.

T. tetragonioides is regarded as native in from China and Korea to Japan, Australia and New Zealand (Allan et al., 1961; Ohwi, 1965; Kim, 2005; Morris and Duretto, 2009; eFloras, 2013). It is probably native in other sites in between these countries as it can spread naturally via ocean currents (Abe, 2006). However, this ability to spread by ocean currents is shared by others in the genus, which could potentially lead to an overestimation of its native range.

It was collected in South America in 1847 (Ugarte et al., 2011); by some accounts, T. tetragonioides may be native in South America (Morong and Britton, 1893; Sturtevant, 1919; Roskruge, 2011), but now most authors now class it as a cultivated, adventive or naturalized plant there (Macbride and Dahlgren, 1937; Zuloaga and Morrone, 1996; Ugarte et al., 2011; Zappi, 2014).

T. tetragonioides was reported by Captain Cook and eaten by his crew in 1770. Joseph Banks is credited with giving seeds to Kew Botanic Gardens, UK, in 1772, and by 1824 it was on sale in London. It then probably spread throughout Europe rather quickly (Sturtevant, 1919). Wild populations were established in France in the 1920s (Tempére, 1920).

T. tetragonioides was on sale in New York in seed catalogues in 1828 after initially being spread by members of a horticultural society (Sturtevant, 1919; Roskruge, 2011). It was recorded wild in California in 1891 and Hawaii in 1909. It was already known in South America by the mid to late 1800s (Morong and Britton, 1893; Reiche and Philippi, 1898; Sturtevant, 1919; Ugarte et al., 2011).

The timing of the spread is harder to pinpoint in Africa, but it is clearly widely planted there (Grubben, 2004). Its suitability as a vegetable in coastal habitats means that it has been introduced to many oceanic islands for human consumption (PIER, 2014). By all accounts the plant is probably more widely distributed than is documented here. 

Soil reaction

• acid
• neutral

Soil texture

• light
• medium

Special soil tolerances

• infertile
• saline
• shallow

Natural dispersal (non-biotic)

The floating horned seeds of T. tetragonioides can be transported by water, including rivers and oceans (Abe, 2006; Nicol et al., 2009). Plants have established on a recently formed volcanic island in the Pacific Ocean, near Japan, apparently from seed transported naturally on ocean currents (Abe, 2006).

Vector transmission (biotic)

T. tetragonioides has not been associated with animal dispersal in the literature, but transport of plants for bird nesting materials could be possible, as could ingestion by tortoises.

Accidental introduction

Plants have been dispersed in bird seed in Britain (Hanson and Mason, 1985).

Intentional introduction

This plant has been deliberately introduced around the world as an easy-to-grow spinach alternative (Sturtevant, 1919; Cambie and Ferguson, 2003; Roskruge, 2011).

There are no reports of T. tetragonioides impacting crops. Costs of control in terms of labour and herbicide costs are not recorded. It is grown as a crop in Israel, and as a common garden plant around the world (APHIS, 2004; Grubben, 2004; Roskruge, 2011).

Impact on habitats

T. tetragonioides is known to establish significant populations in coastal habitats outside of its native range, including dunes, salt marshes and coastal cliffs in Hawaii, Florida, California and Reunion (Robbins, 1940; Starr and Starr, 2006; Zomlefer et al., 2007; Soubeyran, 2008).

Impact on biodiversity

The spread of T. tetragonioides outside of its native range in coastal habitats is not associated with many accounts of its negative impacts on individual species. The spreading habit (almost vine-like) and abundant fleshy leaves of T. tetragonioides give it significant competitive ability. It competes with common native plants like Ipomoea imperati on white sand beaches in Hawaii (Rick Warshauer USGS-Biological Resources Division, Kilauea, Hawaii). It is one of several dominant species in Korean dunes (Kim, 2005).

T. tetragonioides is a common garden plant around the world and has potential medicinal applications (Okuyama and Yamazaki, 1983; Cambie and Ferguson, 2003; APHIS, 2004; Grubben, 2004; Roskruge, 2011).

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Is a habitat generalist
• Pioneering in disturbed areas
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Ecosystem change/ habitat alteration
• Modification of successional patterns
• Monoculture formation
• Threat to/ loss of native species

• Competition - monopolizing resources
• Competition - shading
• Competition - smothering
• Competition - strangling
• Pest and disease transmission
• Interaction with other invasive species
• Rapid growth

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately
• Highly likely to be transported internationally illegally
• Difficult to identify/detect as a commodity contaminant

Economic value

T. tetragonoides is rarely cultivated as a crop for sale in large quantities, though it appears to have been imported into the United States from Israel for sale (APHIS, 2004), and may occasionally be sold in markets in Africa (Grubben, 2004). It is cultivated worldwide by gardeners as an easy to grow leafy green.

Social benefit

The fresh shoots of T. tetragonoides can be eaten raw, but leaves are generally cooked. 100 grams of T. tetragonoides is 94 g water, protein 1.5 g, fat 0.2 g, carbohydrate 2.5 g, Ca 58 mg, P 28 mg, Fe 0.8 mg, vitamin A 4400 IU, thiamin 0.04 mg, riboflavin 0.13 mg, niacin 0.5 mg, folate 15 µg and ascorbic acid 30 mg; it provides 59 kJ or 14 calories (Grubben, 2004). However, much of the calcium is present as oxalates and not available to the human body. Eating it raw has been discouraged because of the high saponin content (Grubben, 2004).