Gossypium tomentosum
Genus
Gossypium
Species
tomentosum
Hawaiian Names with Diacritics
- Huluhulu
- Maʻo
Hawaiian Names
- Huluhulu
- Mao
Common Names
- Hawaiian cotton
Synonyms
- Gossypium hirsutum f. tomentosum
- Gossypium sandvicense
Did You Know…?
The native Hawaiian cotton, or maʻo, helped to save the cotton industry in modern times. When maʻo is crossed with other cotton strains, the resulting commercial hybrids are less attractive to insect pests that destroy cotton crops.
Distribution Status
Endemic
Endangered Species Status
At Risk
Plant Form / Growth Habit
- Shrub
Mature Size, Height (in feet)
- Shrub, Dwarf, Less than 2
- Shrub, Small, 2 to 6
Mature Size, Width
Mature maʻo have about a 5- to 7-foot spread. Plants should have a height to width ratio of 2:1.
Life Span
Long lived (Greater than 5 years)
Landscape Uses
- Accent
- Container
- Ground Cover
- Hedges
Additional Landscape Use Information
If maintained properly by controlling insect pests, providing full sun, and not over watered, maʻo is a wonderful landscape shrub.
Do not plant near automated sprinkler irrigation system as these tend to over water these shrubs causing black sooty mold on leaves, stems and trunk. [David Eickhoff, Native Plants Hawaiʻi]
The bright yellow flowers, and the silvery green foliage with interesting leaf shape add another visual appeal in the landscape.
When planting out to a site, please keep in mind that maʻo hybridizes with other cottons introduced to the islands. Alex Lehman, University of Hawaiʻi at Mānoa, cautions that "this ability for hybridization (or gene flow) can severely impact the fragile genetic identity of maʻo. Couple with habitat degredation, the survival of this beautiful and culturally significant island endemic is unceratin in the the wild." He continues, "to minimize the risk of gene flow, it is recommended that non-native species (any cotton species that produces white lint fiber) not be planted as ornamentals, especially if near native maʻo habitat (leeward, coastal arid environments) or other known maʻo plantings." [11]
Companion Plants:
Kuluʻī, ʻilima, naio* and other dry forest or coastal shrubland plants.
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* These plants can be found on this website using the "Browse Plants" feature found at the top. Enter names without diacritics.
Source of Fragrance
- No Fragrance
Plant Produces Flowers
Yes
Flower Type
Showy
Flower Colors
- Yellow
Additional Flower Color Information
Flowers are bright lemon yellow.
Blooming Period
- Summer
- Fall
- Winter
Additional Blooming Period and Fruiting Information
Maʻo blooms from late summer through winter. Brown capsules containing light brown fuzzy seeds follow the blooming period.
Plant texture
- Medium
Additional Plant Texture Information
The leaves are 3- to 5-lobed. They are from 1 to almost 4 inches wide and are wider than they are long.
Leaf Colors
- Light Green
- Medium Green
Additional Leaf Color Information
Leaf color of maʻo ranges from medium green to grayish silver.
Additional Pest & Disease Information
Maʻo is especially subject to infestations by ants, scale, mealy bugs, and aphids. White flies and red spider mites can also be problematic at times.
Fertilizer
An application of a balanced slow release fertilize with minor elements for potted plants.
For shrubs newly planted in the ground, foliar feed for a few months with kelp or fish emulsion, or a water-soluble fertilizer with a dilution of one half to one third of recommended strength. Applying too much fertilizer, especially with high nitrogen content, for maʻo as often results in large, floppy leaves, fewer flowers, and attract pests. Once established, leave maʻo alone and reduce fertilizing to nil. [David Eickhoff, Native Plants Hawaiʻi]
Pruning Information
Once established, maʻo can be pruned to control spread or height and to keep it bushy.
Brown seed cases and remaining seeds can be removed after a while.
Water Requirements
- Dry
Additional Water Information
These xeric shrubs do not require much water to stay healthy and flower. Mulching with cinders or the like helps retain moisture and slowly adds nutrients to the ground.
Basically, when maʻo is established on a growing site, there is no need to fuss with it. Rarely will you actually need to water a mature maʻo. If you are one that cannot keep your fingers off the hose, this may not be the shrub for you.
Soil must be well drained
Yes
Light Conditions
- Full sun
Additional Lighting Information
Maʻo does best in full sun.
Spacing Information
Plants should be spaced 3 to 6 feet apart for a hedge appearance; further apart to showcase shrubs.
Tolerances
- Drought
- Brackish Water
- Wind
- Salt Spray
- Heat
Soils
- Clay
- Cinder
- Coral
Limitations
Avoid waterlogged soils. Maʻo does not do well in continuous high rainfall locations but does well in mauka regions if given adequate sunshine and soil drainage. [10]
Natural Range
- Niʻihau
- Kauaʻi
- Oʻahu
- Molokaʻi
- Lānaʻi
- Maui
- Kahoʻolawe
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
Maʻo can be found growing in coastal plains to dry forests primarily on the leeward sides of all major islands except Hawaiʻi island, and apparently no longer naturally found on Kauaʻi. [1]
Special Features and Information
General Information
Gossypium tomentosum is a member of the Mallow or Hibiscus family (Malvaceae). Worldwide, there are about 40 species in the genus Gossypium.
Maʻo is classified as a New World cotton and is the only member of that group not cultivated. [1]
Etymology
The generic name Gossypium is derived from the Greek name for cotton, gossypion.
The specific epithet tomentosum from the Latin tomentosus or tomentose, meaning "covered with tangled or matted, woolly hairs."
Hawaiian Name:
The name maʻo comes from the Hawaiian word ʻōmaʻo for green and shares the same name as the native Hawaiian thrush, ʻōmaʻo (Myadestes obscurus) which has a greenish cast to its feathers.
Background Information
It is unfortunate that some have considered maʻo as a "weed" when it is certainly not a common species in many natural areas in the Hawaiian Islands. [7]
Early Hawaiian Use
Dye:
The early Hawaiians used the leaves for a light green (ʻōmaʻomaʻo) or a rich red-brown dye. [2,8] Isabella Abbott notes that "any green kapa deserves close scrutiny, too, for the green obtained from maʻo leaves is fleeting, fading within a few days. The Bishop Museum collection contains no kapa that has retained its green coloration, but a few pieces may once have been green, judging by their overall design." [9]
The flower petals also produced a yellow dye. [2]
Food:
The flowers were sun dried and eaten. Other plant parts were made into a liquid for consumption. [5]
Lei:
Maʻo flowers were used in lei making. [8]
Medicinal:
Apparently, the fibers were also used for medicinal applications much as a cotton swab would be used today. [3] For severe stomach cramps, the dried flowers were eaten along with other plants while also drinking a tea made with maʻo bark and other plants. [6] The flowers and bark of tap roots mixed with other ingredients were used to treat gripping stomach aches, such as during childbirth. [5]
Other Uses:
Although the fibers were once used by early Hawaiians for stuffing pillows, it was not used as a fabric. [3]
Modern Use
There is so much to learn about our flora. The following example of maʻo underscores the value of saving our native plants.
Breeding maʻo an with other closely related species is possible. The native Hawaiian cotton, or maʻo, helped to save the cotton industry in modern times. When maʻo is crossed with other cotton strains, the resulting commercial hybrids are less attractive to insect pests that destroy cotton crops.
Cotton for cloth manufacturing is obtained from the fuzzy seed coating found in the fruit or capsules. Four species are used commercially cotton species with the Upland cotton (Gossypium hirsutum) generating about 90% of industry use, and American Pima or Sea island cotton (G. barbadense) with 8%--both naturalized species in Hawaiʻi. The remaining 2% between two other species (G. arboreum, G. herbaceum). [4]
A commercial cotton industry was started in Kailua, Hawaiʻi Island in 1838 and lasted for about a century, but never became an important trade.
Additionally, there is interest in other agronomic traits of maʻo, such as natural brown lint and heat tolerance. [11]
Though this beautiful shrub has declined in many areas, there have been some successful restoration stories as well. Alex Lehman, University of Hawaiʻi at Mānoa, notes one of these on Oʻahu: "When off-roading near Makapuʻu lighthouse was halted, the maʻo population made a dramatic resurgence. Today, if you walk the trails between Sandy Beach and Makapuʻu in the springtime you will be greeted by hundreds of flowering maʻo hidden amongst the koa haole and buffel grass." [11]
Additional References
[1] "Hawaii's Vanishing Flora" by Bert Y. Kimura, page 62.
[2] "Plants in Hawaiian Culture" by Beatrice H. Krauss, page 66.
[3] "Amy Greenwell Garden Ethnobotanical Guide to Native Hawaiian Plants & Polynesian Introduced Plants" by Noa Kekuewa Lincoln, page 25.
[4] http://en.wikipedia.org/wiki/Gossypium [accessed 10/13/09]
[5] http://www.k12.hi.us/~waianaeh/HawaiianStudies/index.html [accessed 8/21/07]
[6] "Native Plants Used as Medicine in Hawaii" by Beatrice Krauss, page 34.
[7] "Handbook of Hawaiian Weeds" by E. L. Haselwood, page 250.
[8] "Nā Lei Makamae--The Treasured Lei" by Marie A. McDonald & Paul R. Weissich, page 91.
[9] "Lāʻau Hawaiʻi: Traditional Hawaiian Uses of Plants" by Isabella Aiona Abbott, page 57.
[10] "How to Plant a Native Hawaiian Garden" by Kenneth M. Nagata, page "Maʻo."
[11] "Meet Maʻo" by Alex Lehman in "Hawaii Landscape" Sept./Oct. 2013 issue, page 26.
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