Gouania vitifolia
Rhamnaceae or Buckthorn family
Synonyms: Gouania bishopii, Gouania hawaiiensis
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No Known Ancient Hawaiian Name (See Hawaiian Name below)
Gouania, Oʻahu chewstick, Gray chewstick
Natural Range & Environment
Endangered and endemic to the dry forests and open scrub/grasslands, ca. 350 up to 520 m (ca. 1150-1705 ft) on Oʻahu (Waiʻanae Mountains), West Maui (Lāhainā, extinct), and Hawaiʻi Island (Kaʻū District) [Flora of the Hawaiian Islands].
Gouania vitifolia with its "grape-like" foliage and tendrils. Flowers and fruits are rather drab and inconspicuous.
Description
Gouania vitifolia is a climbing shrub with strong, pliable branches and tendrils to firmly attach it to any nearby tree or shrub. It can also grow as a prostrate shrub. Leaves are shed during dry periods. The white flowers are tiny but numerous, clustered on inflorescences. The fruits are less than a half inch (10 mm) with 2-3 wings, rarely 4, yellow-green when immature and brown or black when ripe.
Growth Requirements
General
Gouania vitifolia is rather easy to grow in sunny, open areas with large shrubs or trees to support its vining nature. Too much shade and water can result in leggy, perhaps weak, plants. Watering should be reduced to nearly nothing after being established.
It also does well on fences and large trellises. It may be described as a passively aggressive grower, that is, it will grow quickly but not overwhelm a supporting host to the point of blocking all the sun and sending it into decline, as alien vines such as lilikoi (Passiflora spp.) will do. Without any support, it will grow as a prostrate shrub.
Cultivated plants seem to be nearly in constant bloom or with short periods of rest before blooming again. If required, it can be generously pruned in the landscape with no apparent ill effects on the plant.
It is hoped that this wonderful vining shrub will become more readily available as it is easy to grow, adds another visual aspect to the landscape, and is one of the few native vining plants. It may even prove to have beneficial uses in the near future.
Pests and Diseases
Whiteflies and spider mites can become problematic, but usually do not kill the plant. Refer to the Pests & Diseases page for treatments.
Uses
Ancient Hawaiian
No known uses.
Modern
Although there is no record of ancient Hawaiians using chewstick, other species outside of the Hawaiian Islands do. One such species is the Urban chewstick, also known as white root (Gouania lupuloides), which is commonly used by people in Florida, the Caribbean, Mexico, and Central and South America as a natural tooth cleaner. The chewstick, which is about the thickness of a small finger, is chewed with the bark removed to strengthen the gums. When chewed, the stick produces a slightly bitter yet aromatic, soap-like froth due to the presence of saponins. The softened stick is then used to rub the teeth, similar to a toothbrush [Austin 2004].
In the past, dried and powdered forms of chewstick were exported to Europe and the United States. Jamaicans continue to use chewstick for medicinal purposes and in a mouthwash called Chew-Dent. It is also used in the production of ginger beer, a stronger version of ginger ale. Additionally, chewstick is used as a hops substitute in brewing beer, which may explain the distinctive taste of some Jamaican beers [Austin 2004].
The question remains: will our native Gouania spp. offer similar or even superior benefits? As an experiment, I (Eickhoff) personally tried to use this species as a chewstick because of its similarity to Gouania lupuloides. My results? Inconclusive.
Special Features and Information
General
There are between 50-70 Gouania species found in tropical to subtropical regions around the world, all belonging to the Buckthorn family (Rhamnaceae).
In the Hawaiian Islands, there are three endemic species of Gouania: Hairy-fruit chewstick (Gouania hillebrandii), Smooth-fruit chewstick (G. meyenii), and Oʻahu chewstick (G. vitifolia). These species are all rare and endangered.
Gouania vitifolia is a vining species that is interestingly a woody vine or liana, unlike the shrub-like characteristics of the other native gouanias. Despite this difference, the flowers and fruit of all three species look quite similar. Once believed to be extinct, this endemic liana was rediscovered in 1990 and is now extremely rare. However, there have been several successful outplantings on both Oʻahu and Hawaiʻi Island since its rediscovery [USFWS 2022; Gouania vitifolia]. Fortunately, it is easy to grow in cultivation, and it is hoped that their numbers will increase, where we will see this in public gardens and in our private landscapes.
Other native species in the same family include the indigenous shrub ʻānapanapa (Colubrina asiatica), as well as two endemic trees, both known by kauila or kawila (Alphitonia ponderosa, Colubrina oppositifolia), with the latter being Critically Endangered (IUCN).
Hawaiian Name
No ancient Hawaiian name is known. For this website, we have chosen to use Gouania or Gouania vitifolia.
Etymology
The genus Gouania is named for Antoine Gouan (1733-1821), a professor and naturalist at Montpellier, France [Gledhill 2008]. The specific epithet vitifolia means "grape-like foliage," named for its grape-like foliage and spiraled "watch spring" tendrils [Austin 2004].
DWE
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