Kōwhai (Māori pronunciation: [kɔːɸai] or [kɔːfai]) are small woody legume trees within the genus Sophora, in the family Fabaceae, that are native to New Zealand. There are eight species, with Sophora microphylla and S. tetraptera being the most recognised[clarification needed] as large trees. Their natural habitat is beside streams and on the edges of forest, in lowland or mountain open areas.[1] Kōwhai trees grow throughout the country and are a common feature in New Zealand gardens. Outside of New Zealand, kōwhai tend to be restricted to mild temperate maritime climates.

Kōwhai flowers

The blooms of the kōwhai are widely regarded as being New Zealand's unofficial national flower.[2][3][4] As such, it is often incorporated as a visual shorthand for the country, such as in Meghan Markle's wedding veil, which included distinctive flora representing all Commonwealth nations.[5]

The Māori word kōwhai is related to words in some other Polynesian languages that refer to different species that look superficially similar, such as Hawaiian: 'ōhai (Sesbania tomentosa), Tahitian: ofai (Sesbania grandiflora) and Marquesan kohai (Caesalpinia pulcherrima).[6] Kōwhai is also the Māori word for the colour yellow.[7] The spelling kowhai (without a macron) is common in New Zealand English.

Species edit

Kōwhai tree in full bloom, before foliage has emerged

The eight species of kōwhai are:[3]

Description and ecology edit

Sophora tetraptera foliage
Sophora tetraptera flowers, foliage and seed pods

Most species of kōwhai grow to around 8 m high and have fairly smooth bark with small leaves. S. microphylla has smaller leaves (0.5–0.7 cm long by 0.3–0.4 cm wide) and flowers (2.5–3.5 cm long) than S. tetraptera, which has leaves of 1–2 cm long and flowers that are 3–5 cm long.[citation needed]

The very distinctive seed pods that appear after flowering are almost segmented, and each contains six or more smooth, hard seeds. Most species have yellow seeds, but Sophora prostrata has black ones. The seeds of Sophora microphylla can be very numerous and the presence of many hundreds of these distinctively yellow seeds on the ground quickly identifies the presence of a nearby kōwhai tree. Many species of kōwhai are semi-deciduous and lose most of their leaves immediately after flowering in October or November, but quickly produce new leaves. Flowering of kōwhai is staggered from July through to November, meaning each tree will get attention from birds such as tūī, kererū and bellbird.[10] Tūī are very attracted to kōwhai and will fly long distances to get a sip of its nectar.[citation needed]

The wood of kōwhai is dense and strong and has been used in the past for tools and machinery.[1]

Sophora is one of the four genera of native legumes in New Zealand; the other three are Carmichaelia, Clianthus, and Montigena.[9]

Studies of accumulated dried vegetation in the pre-human mid-late Holocene period suggests a low Sophora microphylla forest ecosystem in Central Otago that was used and perhaps maintained by giant moa birds, for both nesting material and food. The forests and moa no longer existed when European settlers came to the area in the 1850s.[11]

Cultivation edit

Kōwhai can be grown from seed or tip cuttings in spring and autumn.[12] The dark or bright yellow seeds germinate best after chitting and being soaked in water for several hours. They can also benefit from a several minute submersion in boiling water to soften the hard shell and then being kept in the same water, taken off boil, for several hours to soak up the water.[13] Young kōwhai are quite frost tender, so cuttings or seedlings should be planted in their second year when they are 30 cm or higher.[14]

If grown from seed, kōwhai can take many years to flower, the number of years varies depending on the species.[15]

S. prostrata, sometimes called "little baby", is used as a bonsai tree. It grows up to two metres high, has divaricating[16] stems, and sparse smallish leaves.[17]

Toxicity edit

All parts of the kōwhai, particularly the seeds, are poisonous to humans.[18] However, there do not appear to have been any confirmed cases in humans of severe poisoning following ingestion of kōwhai in New Zealand.[19]

Traditional Māori use edit

Traditionally the Māori used the flexible branches as a construction material in their houses and to snare birds. The kōwhai flowers were a source of yellow dye. Also, when the kōwhai flowers bloom, in late winter and early spring, it is time to plant kumara (sweet potato).[20]

Māori also used the kōwhai tree as medicine. Wedges made of kowhai stem were used to split wood, it was used for fences and in whare (Maori hut) construction, implements and weapons.[21] The bark was heated in a calabash with hot stones, and made into a poultice to treat wounds or rubbed on a sore back[22] or made into an infusion to treat bruising or muscular pains.[23] If someone was bitten by a seal, an infusion (wai kōwhai) was prepared from kōwhai and applied to the wounds and the patient was said to recover within days.[22]

References edit

  1. ^ a b Poole, Alec Lindsay (1966). "Kowhai". An Encyclopaedia of New Zealand. Retrieved 8 September 2012.
  2. ^ "Kowhai" in New Zealand A to Z.
  3. ^ a b "Kōwhai". Department of Conservation. Retrieved 17 October 2023.
  4. ^ "Nationhood and identity", in Te Ara Encyclopedia of New Zealand.
  5. ^ "The Wedding Dress: Clare Waight Keller for Givenchy". The Royal Household, UK. 19 May 2018.
  6. ^ "Kōfai". Te Māra Reo: The Language Garden. Benton Family Trust. 2022. Retrieved 30 September 2022.
  7. ^ "kōwhai". Te Aka.
  8. ^ "Sophora". Integrated Taxonomic Information System.
  9. ^ a b Weir, Bevan. "Taxonomy of New Zealand Native Legumes". NZ Rhizobia. Retrieved 17 October 2023.
  10. ^ Campbell, Kirsten L. (2006). A study of home ranges, movements, diet and habitat use of kereru (Hemiphaga novaeseelandiae) in the southeastern sector of Banks Peninsula, New Zealand (MSc thesis). Lincoln University. hdl:10182/347.
  11. ^ Pole, Mike (31 December 2021). "A vanished ecosystem: Sophora microphylla (Kōwhai) dominated forest recorded in mid-late Holocene rock shelters in Central Otago, New Zealand". Palaeontologia Electronica. 25 (1): 1–41. doi:10.26879/1169. ISSN 1094-8074. S2CID 245807815.
  12. ^ "Native Plants at Piha". Archived from the original on 14 October 2008. Retrieved 17 January 2009.
  13. ^ "Raising Native Plants From Seed". Hawke's Bay Regional Council. 2004. Archived from the original on 14 October 2008. Retrieved 21 May 2009.
  14. ^ "Native plant information". Trees for Survival. Archived from the original on 8 February 2009. Retrieved 17 January 2009.
  15. ^ Lee, Melody (2017). "How to Plant Kowhai". Garden Guides.
  16. ^ The Development and Genetic Variation of Sophora prostrata – A New Zealand Divaricating Shrub (MSc thesis). 2014. Retrieved 30 December 2022.
  17. ^ Hughes, Denis (2002). "Sophora – The Kowhais of New Zealand" (PDF). Combined Proceedings International Plant Propagators' Society. 52. Archived from the original (PDF) on 29 March 2013. Retrieved 5 November 2008.
  18. ^ "Poisonous Plants at the Royal New Zealand Institute of Horticulture". Retrieved 20 May 2008.
  19. ^ Slaughter, Robin; Beasley, Michael; Lambie, Bruce; Wilkins, Gerard; Schep, Leo (2012). "Poisonous plants in New Zealand: a review of those most commonly enquired about to the National Poisons Centre". The New Zealand Medical Journal. Archived from the original on 9 January 2013. Retrieved 27 March 2013.
  20. ^ "Sophora microphylla (Kowhai)". Taranaki Educational Resource: Research, Analysis and Information Network. Archived from the original on 25 August 2012. Retrieved 31 August 2012.
  21. ^ Kowhai • Tāne’s Tree Trust (tanestrees.org.nz)
  22. ^ a b Jones, Rhys (2 March 2009). "Rongoā – medicinal use of plants – Other medicinal plants". Te Ara – the Encyclopedia of New Zealand. Retrieved 8 November 2010.
  23. ^ Durie, Sir Mason (June 2010). "Te whakahaumanutanga me te oranga hinengaro o mua – Ka mātaia ngā huanga o te rongoā – Traditional healing and mental health: measuring the effectiveness of rongoā" (PDF). Best Practice Journal (28). Best Practice Advocacy Centre: 5–7.