Native Plants of Hawai‘i - Wikstroemia sandwicensis

Wikstroemia sandwicensis

Thymelaeaceae or ‘Ākia family [Wagner et al. 1990]; also sometimes referred to as the Daphne family or Stringbarks

Synonyms: Diplomorpha sandwicensis, Wikstroemia fauriei, Wikstroemia multispicata, Wikstroemia perdita

ʻĀkia

Kauhi (See Hawaiian Name below)

Variableleaf false ohelo

Natural Range & Environment

Wikstroemia sandwicensis is endemic to Hawai‘i Island, where it seems to be most common in the southern half of the island. It is found in a diversity of dry to wet habitats from near sea level to 1,500 m (4,921 ft) [Wagner et al. 1990] and has not been formally recorded from the Kohala Mountains, where its sister species, W. pulcherrima, is common.

While the tubular shape of ʻākia flowers is one of its more consistent features, the color of its flowers can vary (photograph of yellow flowers courtesy of Drew Kapp CC BY-NC 4.0; header photograph of green flowers courtesy of Karl Magnacca CC BY-NC 4.0). Like most other Hawaiian Wikstroemia, W. sandwicensis has small fleshy drupes that turn red when ripe, often attracting hungry birds (photograph courtesy of J.B. Friday ©). Some W. sandwicensis appear to be unique in developing very large juvenile or sucker leaves, something worthy of further scientific/taxonomic investigation (photograph courtesy of Karl Magnacca CC BY-NC 4.0).

W. sandwicensis is probably the tallest of all the Hawaiian Wikstroemia, sometimes having an impressively wide trunk (photograph of ʻākia among hāpuʻu and its large trunk courtesy of Karl Magnacca CC BY-NC 4.0). Potted W. sandwicensis ready for sale at a Hawai‘i Island nursery. If you look closely in the center, you can see one of these ʻākia is already producing flowers. A larger but still relatively small cultivated W. sandwicensis in the ground. (Photographs of potted and in-the-ground W. sandwicensis courtesy of Cory Edging (Māla Lā’au Hawai’i) ©.)

Description

Wikstroemia sandwicensis can be anywhere from a shrub (more common in open spaces) to a sizable tree (seen in closed-canopy forests) up to about 30 feet (9 m) tall with a lifespan well in excess of five years. Its branches are often reddish brown with whitish lenticels near the leaf scars (giving the stems a banded appearance) but can also be yellow or gray. The trunk of older trees tends to be gray and is frequently covered with lichens or moss. ʻĀkia bark is fibrous and very strong (see Uses; Ancient Hawaiian below).

Wikstroemia sandwicensis is aptly named "Variableleaf false ohelo" because of the extreme variation in the size (and to a lesser extent the shape) of its leaves. Small-leaved, narrow-leaved, and large-leaved forms are all common, sometimes with different sized leaves on the same plant [Wagner et al. 1990]. Particular to W. sandwicensis is the extremely large sucker or juvenile leaves sometimes seen at the base of large trees (see photograph above). This characteristic, along with other differences between montane forest forms and the coastal or lowland forms, should probably be formally investigated. Regardless of their size and shape, W. sandwicensis leaves are typically hairless (or nearly so), with the lower surface usually being a lighter color than their upper surface.

Wikstroemia sandwicensis produces clusters of usually yellow (but sometimes green) tubular unisexual flowers, typically with plants being either male or female. The flowers produce a pleasant fragrance, especially at night. Pollinated flowers develop into small ovoid berries (drupes) that turn from green (unripe) to bright red when ripe. Within each berry is one elliptical seed.

Growth Requirements

General

If your wish is to grow an ʻākia tree rather than an ʻākia shrub, Wikstroemia sandwicensis is probably your best bet. However, out in the open, W. sandwicensis typically takes on a shrubby form and requires deliberate but cautious pruning of its lower branches to hasten a treelike shape; avoid removing a bunch of lower branches all at once since this can stress your plant and invite infection. Because of its potentially large size, it is probably not the best species to pick if you want to keep your ʻākia in a container long-term. Lastly, there's still a lot we don't know about the toxicity of this and other ʻākia species (see Uses below). Therefore, until we know more, we recommend not planting ʻākia in any areas frequented by small children (e.g., daycares, play areas).

Wikstroemia sandwicensis will grow the quickest if planted in a site receiving direct sunlight for most of the day. However, it will also grow in a shaded but brightly lit space, albeit not as quickly. While this ʻākia species can withstand (lowland) heat and drying winds, it cannot withstand drought as well as some other ʻākia species (e.g., W. uva-ursi), and the soil surrounding it should be kept moist at all times. My (Koebele) plantings have been limited to rocky clay soil. However, John Culliney [Culliney & Koebele 1999] has successfully grown W. sandwicensis in calcareous sandy soil. As with most native Hawaiian plants, ʻākia seems to do best in soil or media that easily drains water.

Wikstroemia sandwicensis grows quickly. John Culliney's [Culliney & Koebele 1999] plants grew to 13 feet (4 m) after six years outside his home in Waimānalo, O‘ahu. Also, don't be surprised to see even small ʻākia, one to two years old, begin to flower (see photograph above). I never fertilized my in-the-ground ʻākia with anything more than a yearly topdressing of compost. While still in their pot, I applied a balanced controlled-release fertilizer every six months to a year or used a foliar fertilizer diluted to one-half the recommended strength every few months.

I (Koebele) have only grown Wikstroemia sandwicensis a few times, and the plants were either male or female. Therefore, if your goal is to display a plant with colorful berries or collect seeds for propagation, it would be wise to plant several W. sandwicensis in your landscape to ensure you have at least one plant producing male flowers and one plant producing female flowers.

Pests and Diseases

Few pests seem to bother ʻākia. However, you may infrequently encounter an infestation of scale insects, usually farmed and protected by ants. Refer to Pests & Diseases for ways to deal with scale insects and ants. A more common occurrence is leaf-cutter bees removing semicircular sections from an ʻākia's leaves. Lilleeng-Rosenberger [2005] has noted that chickens will eat ʻākia fruits and scratch at and expose the plant's roots.

Uses

Ancient Hawaiian

All the formally recognized native species of Wikstroemia in Hawai‘i (currently 12 species) have the common Hawaiian name ‘ākia. And, while according to Pukui & Elbert [1986], some "varieties" were given qualifying adjectives such as lau nui (large leaf), mānalo (sweet, safe from harm), and pehu (swollen), it's currently impossible to attribute ancient species-specific uses to any Hawaiian Wikstroemia species. Therefore, the following is a collection of all the ancient Hawaiian uses of "‘ākia" we were able to find in the literature.

Perhaps the most interesting ancient use of ‘ākia was to catch fish, a process called hola. Hawaiian fishermen, using a nearby rock, would pound the bark and leaves of ‘ākia and then place double handfuls of the mash inside a sheath of coconut leaf or twisted grass. This was then placed under the water, most often in a tidepool but sometimes in deeper water or a stream. Within about ten minutes, the narcotic poison would cause the fish to swim about aimlessly or float to the surface, where they were easily collected. Although the ‘ākia poison often killed the fish, it did not taint their flesh, which could be eaten without concern [Degener 1973].

While fish poisoned and caught using ‘ākia were safe to eat, apparently the ‘ākia poison itself was not. Degener [1973] and others state that the poison, while harmless to the touch, was extremely poisonous if eaten. He further describes that a deadly drink, prepared with the root and bark of ‘ākia along with several other plant parts, was used for suicide and the execution of criminals. Supposedly, the person giving the doomed person the poison in a cup called apukoheoheo would sarcastically say, "He wahi mea ola ia" ("This is to keep you alive.").

The strong fibrous bark of many species of Thymelaeaceae has been used worldwide for cordage [Britannica], and ‘ākia in Hawai‘i was no exception. Peterson in Wagner et al. [1990] has an excellent review of Hawaiian Wikstroemia fiber use and strength, where he states, "Species of Wikstroemia have furnished one of the strongest Hawaiian fibers, used in making ropes and braids. It is also said to have been used in making kapa." He goes on to say that measurements made at the Swedish Institute for Textile Research have shown that the fibers from W. oahuensis var. oahuensis branches desiccated for six months were about the same density as that of New Zealand flax (Phormium tenax) and ramie (Boehmeria nivea). And, in another study by Beatrice Krauss using traditional Hawaiian methods, cord made from W. oahunesis bark had half the tensile strength of Tossa jute (Corchorus olotorius).

Additional ancient uses of ‘ākia include the following:

Lamb [1981] claims ‘ākia wood was used as ‘auamo (carrying pole) or beating sticks.
Kamakau [1964], page 126, describes ‘ākia being used in an ‘ana‘ana magic ceremony: "In preparing for the prayer ritual of a kuni ceremony, the kapuahi kuni, the ritual fireplace, was set blazing with ho‘awa and ‘akia with stalks and leaves still green."
ʻĀkia berries were used in lei-making [Abbott 1992; Krauss 1993].
According to Ka‘aiakamanu & Akina [1922], ‘ākia, mixed with several other plant parts, was used as a laxative or to treat asthma.

For the reader interested in the many ancient Hawaiian uses of ‘ākia, Medeiros et al. [1998] provide an extensive review along with a more comprehensive list of ethnobotanical and historical sources than I present here.

Modern

ʻĀkia berries are sometimes used in lei-making [McDonald & Weissich 2003].

Is ʻĀkia Poisonous?

The short answer, given the recorded uses described above, is "Yes, you should always consider ‘ākia poisonous," and always treat it appropriately, particularly when making planting decisions (e.g., not a smart choice for landscaping a daycare or children's playground). However, what do we really know about the toxicity of ‘ākia? Well, unfortunately, I (Koebele) was unable to find any comprehensive scientific study on the toxicity of Hawaiian Wikstroemia, and nearly all the recorded "data" on this subject is anecdotal. Most scientific investigations of Wikstroemia chemistry have been conducted on the non-Hawaiian species W. indica and have focused on its potential pharmacological uses.

Handy & Handy [1972], page 214, describe two types of ‘ākia: an “‘Akia ‘awa (bitter ‘akia). A shrub that bears orange-red fruits. Decoctions of bark and roots are deadly poisonous, and were used for killing and suicide” and “‘Akia manalo (mild ‘akia). Not poisonous; the bark and leaves were used as a narcotic.” Unfortunately, while their description of ‘Akia ‘awa (i.e., orange-red fruits) corresponds with Hawaiian Wikstroemia species, Handy & Handy do not provide a description of ‘Akia manalo.

Neal [1965], page 616, states without citation that "No part of the plant has been found to be poisonous to mammals" in her description of Wikstroemia. Similarly, Arnold [1944], pages 58 & 59, describes personally eating ‘ākia fruits and leaves and feeding an alcohol extract of bark to two guinea pigs without any ill effects to himself or the animals. Arnold concluded that "the plant is not as poisonous as it is commonly reputed to be, and it is easily possible—indeed, the writer considers it likely—that it is not poisonous at all."

More recently, Medeiros et al. [1998] note that "the fruit is slightly bitter but eaten by birds"; however, the "foliage may be poisonous or at least unpalatable to cattle as it is almost never browsed." Rick Barbosa, co-owner of Hui Ku Maoli Ola, states, "I’ve also seen birds eat the fruits daily with no ill effects and the fruit taste so bad that any human who put it in their mouth would immediately spit it out, you can trust me on that, its terrible" [Hui Ku Maoli Ola]. Lastly, Nagata [1992] refers to the work of Dr. Frank Tabrah on the toxicity of Wikstroemia pulcherrima (to date, I've been unable to find this study). According to Nagata, Tabrah found that W. plucherrima caused mice to go to sleep and that the toxicity of W. plucherrima varied from high to zero even in the same plant at different times.

Special Features and Information

General

Thymelaeaceae is a family of about 890 species of trees, perennial herbs, and lianas in 46 to 50 genera that are found worldwide (but rarely in cold regions) and are particularly common in Africa and Australia. Members of the family have a fibrous bark, with many having an unpleasant odor [Britannica].

Wikstroemia is the only native genus of Thymelaeaceae found in Hawai‘i, where currently (2026), there are 12 formally recognized species, all endemic, with most species restricted to a single main island. W. sandwicensis is found only on Hawai‘i Island [Flora of the Hawaiian Islands].

The common name "false ohelo" is believed to have originated because the orange to red fruits of ʻākia closely resemble the berries of the native and frequently collected ʻōhelo (Vaccinium spp.). ʻĀkia is also sometimes referred to as the "fish poison plant" (see Uses above).

Hawaiian Name

On page 385, under W. foetida var. Oahuensis (a synonym of Wikstroemia oahuensis var. oahuensis), Hillebrand & Hillebrand [1888] make the somewhat obscure statement: "Nat. name: "Akia" or "Akea", the root of which recurs in the Vitian name "Mati". In Tahitian it is called "Ovao"." Some have interpreted this to mean that the Hawaiian name, ʻākia, originated from an ancient name for the related species, Ixora foetida (syn. Wikstroemia foetida), found in Fiji and Tahiti but not in Hawai‘i except under cultivation [Plants of Hawai‘i].

‘Ākia is also the Ni‘ihau name for the endangered endemic Solanum nelsonii, a small native shrub in the Solanaceae or Nightshade family, better known as pōpolo [Wagner et al. 1990].

ʻĀkia can also mean "to ferment; very sour, as poi. ʻAi ʻākia, sour poi" [Pukui & Elbert 1986]. However, it's unclear if this meaning has any relationship to the plant.

Etymology

Wikstroemia is named in honor of Johan Emanuel Wikström (1789–1856), a Swedish botanist and author of several papers on Thymelaeaceae [Wagner et al. 1990].

The species name, sandwicensis, refers to the "Sandwich Islands," as the Hawaiian Islands were once called and named by James Cook on one of his voyages in the 1770s. James Cook named the islands to honor John Montagu (the fourth Earl of Sandwich) for supporting Cook's voyages [Gledhill 2008].

BPK