Cordia subcordata

leaf Main Plant Information

Genus

Cordia

Species

subcordata

Hawaiian Names with Diacritics

  • Kou

Hawaiian Names

  • Kou

Did You Know…?

Kou was thought to be exclusively a Polynesian introduction. Indeed the early Hawaiians did bring the useful kou with them on their journey to the islands. However, recently eveidence of kou was found on Kauaʻi that pre-dates human arrival. Kou is now catagorized as an indigneous to the Hawaiian Islands.

leaf Plant Characteristics

Distribution Status

Indigenous

Endangered Species Status

No Status

Plant Form / Growth Habit

  • Tree

Mature Size, Height (in feet)

  • Tree, Small, 15 to 30
  • Tree, Medium, 30 to 50

Mature Size, Width

Canopy may spread to 25 feet across, often as wide as tall. In the 19th century, kou grew as tall as 50 feet in Hawaiʻi, but defoliation by kou leaf worm as reduced the heights. Such giants may remain in remote areas in the Marshall Islands and the elsewhere in the Pacific, and perhaps over a century old. [7]

Life Span

Long lived (Greater than 5 years)

Landscape Uses

  • Provides Shade
  • Screening
  • Specimen Plant

Additional Landscape Use Information

Kou is an excellent tree for a roomy landscape. They can get to be medium-large trees and may not be suitable for small urban yards that cannot accommodate a height and canopy spread of 25-35 feet. [7] Good to keep in mind that they have a shallow root system and can be damaged by too much surface disturbance. Once established they require little maintenance.

However, the slippery fruits along with exceptionally hard seeds may present a hazzard if planted too close to driveways or along sidewalks where they can a present a real threat for slipping or going an unintentional "skating trip." [7]

In many urban plantings kou is being replaced by kou haole or the Geiger tree, a similar species with red-orange flowers and rough leaves. This is unfortunate because the Geiger tree is a native of the West Indies and has no cultural value in the Hawaiian Islands. [7]

Plant Produces Flowers

Yes

leaf Flower Characteristics

Flower Type

Showy

Flower Colors

  • Light Orange
  • Orange

Additional Flower Color Information

Flower color ranges from light to bright orange.

Blooming Period

  • Year Round
  • Sporadic

Additional Blooming Period and Fruiting Information

Generally, kou fruit all year long, but maybe sporadic. [7] The green fruits soon become brown and then dry to a blackish color when ripe. Inside are four white seeds.

leaf Leaf Characteristics

Plant texture

  • Coarse

Additional Plant Texture Information

Leaves are smooth and somewhat glossy.

Leaf Colors

  • Medium Green

Additional Leaf Color Information

Kou trees with varigated green and white leaves are known. [7]

leaf Pests and Diseases

Additional Pest & Disease Information

The Kou leaf worm (Ethmia nigroapicella), from a moth, can defoliate and can be killed kou trees. The wood is very termite reistant. Large trees can develop heartwood rot. [7]

leaf Growth Requirements

Pruning Information

Kou trees will often grow crooked and pruning is necessary to keep a nice shape. [7]

Water Requirements

  • Dry

Soil must be well drained

Yes

Light Conditions

  • Full sun
  • Partial sun

Additional Lighting Information

Prefers full sun but tolerates some shading. [7]

Tolerances

  • Drought
  • Wind
  • Salt Spray

Soils

  • Clay
  • Sand
  • Cinder
  • Organic
  • Coral

Limitations

Moderately drought tolerant trees. Kou will not grow at higher altitudes and cannot withstand frost. Kou can grow in saline soils and tolerate some salt spray, but heavy spray can severley damage leaves. [7]

leaf Environmental Information

Natural Range

  • Niʻihau
  • Kauaʻi
  • Oʻahu
  • Molokaʻi
  • Lānaʻi
  • Maui
  • Hawaiʻi

Natural Zones (Elevation in feet, Rainfall in inches)

  • Less than 150, 0 to 50 (Dry)
  • 150 to 1000, 0 to 50 (Dry)

Habitat

  • Terrestrial

Additional Habitat Information

Kou is found throughout most of the Main Islands today, but is only known to have occurred for a certainty as an indigenous plant on Kauaʻi in the past. [3]

leaf Special Features and Information

General Information

Kou (Cordia subcordata) is in the Borage or Foget-me-not family (Boraginaceae). Other native members include nama or hinahina kahakai (Nama sandwicensis), hinahina (Heliotropium anomalum var. argenteum), and kīpūkai (H. curassavicum).

Well known non-native kin include the tree heliotrope (Tournefortia argentea) commonly seen along the salty Hawaiian coasts; borage (Borago officinalis), used in European cuisine; comfrey (Symphytum spp.); and kou haole or Geiger tree (Cordia sebestena), a commonly used landscape tree in the islands in urban areas along streets, business districts, public parks, housing common areas, and private yards.

Etymology

The generic name Cordia, is named for Euricius Cordus (1485-1535) and his son Valerius (1515-1544), both German botanists and pharmacists.

The specific epithet is from the Latin sub-, almost or not completely, and cordatus, cordate (with two equal rounded lobes at base) in reference to the leaf shape, literally meaning "almost heart-shaped."

Background Information

Formerly thought to be exclusively a Polynesian introduction, a recent fossil site at Māhāʻulepū, Kauaʻi predates Polynesian arrival where kou samples were found and thus proving that kou is also an indigenous plant. [3,6] The seeds are salt-water tolerate and disperse along coastal areas even on atolls where few other timber trees for wood can grow. [5]

In Papua New Guinea this indigenous tree is known as the Kerosene tree because it burns so easily.

Cordia subcordata is known by a number of local names outside of the Hawaiian Islands, such as Bird lime tree, Glueberry, Kerosene wood, Manjak, Mareer, Marer, Narrow-leafed bird lime tree, Snottygobbles, and Tou.

Early Hawaiian Use

Early Hawaiians certainly brought kou with them as one of the canoe plants since it is such a highly esteemed wood. [5,12]

They were planted as a favorite shade tree around houses and by the seashore. [9] Women would beat their kapa under kou trees. [12]

Kou was considered as one of the best woods for carvings along with the native koa (Acacia koa) and milo (Thespesia populnea), and the Polynesian introduced kamani (Calophyllum inophyllum). [7,8,12] Kou was prized because of the beauty of the grain and ease of cutting and carving. [12]

Dye:

The leaves were used to stain fishing lines a light tan. [5,10,12] The aged leaves were used for a warm brown to red dye for kapa. [1]

Fishing:

Wood was made into fishing hook containers. [12]

Food:

The tasteless seeds were eaten in times of famine or occasionally by hungry children.

Household Furnishings:

Wooden food bowls (ʻumeke kou), meat dishes, cups, platters (pā kou), and calabashes were highly prized as the best of all woods because it did not impart a resinous flavor to the food such as koa and most other native woods. [2,4,8,10]

Lei:

The flowers were used for lei and young girls especially were fond of lei kou. [4,9,12] They were always strung kui style (one behind the other). [10]

Medicinal:

Use to treat ʻea (thrush), a disease of young children. [12]

Religion:

Kou wood was fashioned into images of gods. [12]

Modern Use

The wood is used to carve artifacts such as calabashes, dishes, cups, bowls, paddles, furniture, and drums. [5,11]

Uses Outside of Hawaiʻi:

In Tahiti, fruit of banyan (Ficus sp.) is added to kou leaves to make a beutiful red dye. [12]

Additional References

[1] "Plants in Hawaiian Culture" by Beatrice H. Krauss, page 65.
[2] "Arts and Crafts of Hawaii" by Te Rangi Hiroa (Sir Peter H. Buck), pages 37-38, 187.

[3] "Fossil Evidence for a Diverse Biota From Kauaʻi and Its Transformation Since Human Arrival" by David Burney et al., Ecological Monographs, 71(4), 2001, Ecological Society of America, pages 631, 632, 633.

[4] "Nā Lei Makamae--The Treasured Lei" by Marie A. McDonald & Paul R. Weissich, page 53-54.

[5] "Plants of the Canoe People" by W. Arthur Whistler, pages 83-84.

[6] "Back to the Future in Caves of Kauaʻi--A Scientist's Adventures in the Dark" by David A. Burney, page 106.

[7] "Traditonal Trees of the Pacific Islands: Their Culture, Environment, and Use," pages 305, 307, 309, 312, 313.

[8] "Resource Units in Hawaiian Culture" by Donald D. Kilolani Mitchell, pages 79-80, 120, 130-131.

[9] "In Gardens of Hawaii" by Marie C. Neal, pages 714-715.

[10] "Lāʻau Hawaiʻi: Traditional Hawaiian Uses of Plants" by Isabella Aiona Abbott, pages 57, 87, 127.

[11] "Contemporary Woodworkers" by Tiffany DeEtte Shafto & Lynda McDaniel, page 182.

[12] "Ethnobotany of Hawaii" by Beatrice H. Krauss, page 133.

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