Euphorbia skottsbergii var. skottsbergii
formerly Chamaesyce skottsbergii var. kalaeloana
Euphorbiaceae or Spurge family
Synonyms: Chamaesyce skottsbergii, Chamaesyce skottsbergii var. audens, Chamaesyce skottsbergii var. kalaeloana, Euphorbia multiformis f. pekelonis, Euphorbia skottsbergii, Euphorbia skottsbergii var. audens, Euphorbia skottsbergii var. kalaeloana
ʻAkoko
ʻEkoko, Koko, Kōkōmālei
Coastal sandmat, ‘Ewa Plains ‘akoko
Natural Range & Environment
Euphorbia scottsbergii var. skottsbergii is an endangered deciduous shrub endemic to southwestern O‘ahu (but see Description below). It is found growing exclusively on coralline substrate (i.e., exposed prehistoric reefs), sometimes covered with a thin layer of silty soil. Rainfall in the area is seasonal (peaking during the winter) and sporadic, averaging less than 15 inches (38 cm) a year.
Historically, with a population size estimated to be in the thousands, Euphorbia scottsbergii var. skottsbergii was seen throughout much of Kalaeloa from the present-day Ko Olina Resort and Deep Draft Harbor east to at least the eastern edge of the former US Naval Air Station at Barbers Point (closed in 1999) and possibly as far as the western edge of Pearl Harbor [USFWS 2007]. Over the past 50 years, urban development has been directly responsible for the rapid decline in the number of remaining wild ‘akoko and the restriction of its geographic range such that today (2026) there are less than a thousand plants within two man-made populations (via outplanting) and one semi-natural population (where the majority of ‘akoko are either outplanted or the progeny of outplants).
I (Koebele) have been involved with the preservation of this endangered ‘akoko for many years, so it's difficult not to share ad nauseam its recent sad history. However, if you are interested in reading a more personal account of its history and my involvement, please check out the story on my companion website, www.nativehawaiiangarden.org. What I will say here is that while there are three places in Kalaeloa where this ‘akoko is protected and managed, and that thousands of seeds have been collected and placed in storage, regrettably, the exclusive habitat (i.e., Kalaeloa) of Euphorbia skottsbergii var. skottsbergii continues to be very rapidly covered over with imported upland soil, roads, and buildings.
Like many other ‘akoko, Euphorbia scottsbergii var. skottsbergii produces small specialized inflorescences that have tiny reduced (i.e., no petals or sepals) male and female flowers that sit atop a cup-like base called a cyathium. Each cyathium has one central female flower (with a branched stigma) surrounded by one to several male flowers. If pollinated, the female flower's ovary enlarges to form a fruit capsule that hangs to the side of the cyathium. Here are two close-up photographs: the top photograph shows inflorescences at different stages of development (photograph courtesy of Joel Lau ©); the bottom photograph shows a ripe fruit capsule becoming erect just a few hours before it explodes to disperse its tiny seeds. (My [Koebele] best guess is that the adjacent yellow cyathium is the base of an old inflorescence with either an exploded or unpollinated female flower at its center.) Both wild and cultivated ‘akoko are frequently visited by ladybird beetles, which keep the plants' primary pests, scale insects and mealybugs, in check. No, these ‘akoko are not dead! During the multiple dry periods of the year, this species drops all or most of its leaves to conserve water (Photograph courtesy of kairigney CC BY-NC 4.0.). A much younger self (Koebele) standing among a patch of outplanted mature (about 4 ft [1.2 m] tall) Euphorbia scottsbergii var. skottsbergii.
Description
This ‘akoko species has a complicated and unsettled taxonomic history. Today (2026), some agencies [ECOS] use the scientific name, Euphorbia skottsbergii var. skottsbergii, exclusively for the ‘akoko found growing only in Kalaeloa, O‘ahu, while other institutions [Flora of the Hawaiian Islands] do not. Sherff [1936] first described and named the species and variety as Euphorbia skottsbergii var. kalaeloana. This was later changed to Chamaesyce skottsbergii var. kalaeloana by Degener [1931-] and then changed again to Chamaesyce skottsbergii var. skottsbergii by Wagner et al. [1990]. Between 1990 and 2006, the upright ‘akoko at Kalaeloa, O‘ahu, was referred to as Chamaesyce skottsbergii var. skottsbergii along with a morphologically similar (but prostrate) ‘akoko found on Moloka‘i. Morden & Gregoritza [2006] investigated all the forms of Chamaesyce skottsbergii using RAPD and ITS genetic analysis and concluded there are three forms of the species with the two on Moloka‘i being genetically closer to one another than either was to the form found on O‘ahu. They recommended that the three forms be formally recognized as the varieties, skottsbergii (O‘ahu), audens (Moloka‘i), and vaccinoides (Moloka‘i). Wagner et al. [2012], in an update to the Manual of Flowering Plants of Hawai‘i, subsequently changed the species name, Chamaesyce skottsbergii, back to Euphorbia skottsbergii, but did not change the variety names and their distributions [Flora of the Hawaiian Islands].
Euphorbia skottsbergii var. skottsbergii is an endangered shrub that grows to about four feet (1.2 m) in height and has a lifespan of five to ten years. It tends to have one or two main stems with numerous shorter sidebranches. Older stems are gray while younger stems are reddish brown. It has a milky latex-like sap that may irritate those with sensitive skin; avoid getting the sap in your eyes.
Euphorbia skottsbergii var. skottsbergii has round to elliptic leaves, arranged in pairs opposite each other along the stem. During periods of drought, typically occurring more than once a year, plants will drop all or most of their leaves and can easily be mistaken as dead. Damaged or old leaves turn red, orange, or yellow.
Euphorbia scottsbergii var. skottsbergii produces small specialized inflorescences that have tiny reduced (i.e., no petals or sepals) male and female flowers that sit atop a cup-like base called a cyathium. Each cyathium has one central female flower (with a branched stigma) surrounded by one to several male flowers. Since I (Koebele) have always grown this species in clusters, I do not know if plants are self-fertile. Wild plants produce their small inflorescences whenever there is enough moisture for leaf formation and growth, stopping only during periods of drought while regularly-watered (i.e., cultivated) plants bloom continuously.
The ovary of a pollinated female flower develops into a green capsule that hangs to the side of the cyathium on a stalk as it grows larger. When ripe, typically in the morning hours, the capsule rises up from its downward-curved position and becomes upright shortly before exploding to disperse the few tiny gray seeds inside. Currently, my (Koebele) best guess is that old cyathia with an exploded (or unpollinated) female flower turn yellow.
Growth Requirements
General
Euphorbia scottsbergii var. skottsbergii (hereafter referred to as the ‘Ewa Plains ‘akoko or ‘akoko) is a fast-growing ‘akoko that tends to shoot up straight with one or two main stems along with numerous shorter sidebranches. Because of its slender growth form and small deciduous (during periods of drought) leaves, it's not the best choice for a hedge or screen. Rather, use it as an accent in the landscape, although I (Koebele) find a cluster of three or five plants more attractive than a single plant. A cluster will also increase the possibility of seedlings which can renew the species within the landscape when the parent plants die. Alternatively, you can keep your ‘Ewa Plains ‘akoko in a container; it even does well indoors under LED lights.
The ‘Ewa Plains ‘akoko grows best in a site that receives full sunlight for all or most of the day. However, this species can also tolerate some shading, since wild plants are sometimes seen beneath alien trees such as kiawe (Neltuma pallida). Except for a good watering immediately after planting, avoid overwatering your ‘akoko. Remember, this species receives only about 15 inches (38 cm) of rain per year in its natural habitat and is well adapted to drought.
While wild ‘Ewa Plains ‘akoko are found growing exclusively on hard coralline substrate, I have also successfully grown this species in clay-, cinder-, and organic-dominant soils, provided the soil drained water easily. In pots, cinder-, crushed coral-, or perlite-rich media all work well. The species can tolerate extreme heat and drought, strong winds, and limited salt spray.
As mentioned above, this ‘akoko grows quickly in the ground without watering or fertilizer, and you can expect to have a plant 18 inches (46 cm) tall in a year or less. By this time, your plant should have also flowered and produced fruits. Potted ‘akoko should be regularly fertilized to prevent their leaves from yellowing and prematurely falling off. Use either a balanced controlled-release fertilizer every six months, or an organic or inorganic foliar fertilizer every month or so. ‘Ewa Plains ‘akoko normally self-prune (i.e., older lower sidebranches die and fall away) in the wild. However, if grown too quickly (by giving it too much water or fertilizer), your plant can become top-heavy and fall over. To prevent this from happening, reduce your watering and either support your plant with stakes, etc., or strategically prune your plant to better balance its weight.
In the wild, ‘Ewa Plains ‘akoko naturally lose all their leaves and go dormant several times each year. After your ‘akoko is established in a landscape, it’s your decision if you wish to mimic this natural behavior or circumvent it by watering — the plant will survive either way. (However, again, water sparingly since this species naturally grows in a region where the annual rainfall is only about 15 inches a year.) The maximum height for ‘Ewa Plains ‘akoko is about four feet (see photograph above). And, its maximum lifespan is about ten years. Therefore, be certain to collect and store (in your refrigerator) some seeds early so you don’t get caught without replacement material. ‘Ewa Plains ‘akoko are easy to grow from seed. Refer to the Native Hawaiian Garden website for details on how to collect, store, and propagate ‘akoko seeds.
Pests and Diseases
‘Ewa Plains ʻakoko are occasionally attacked by mealybugs, scale insects, spider mites, and whiteflies; the most commonly seen pest is the cottony cushion scale. However, infestations are rare, and, in the case of mature plants, the pests often disappear over time, probably due to natural predators such as ladybird beetles or leaf shedding. ʻAkoko's milky sap may also deter many pests. Refer to the Pests & Diseases page for ways to deal with each of the above-mentioned pests. Persistent infestations are more likely if you have placed your ‘akoko in an unnatural environment, such as a heavily-shaded or windless site. If possible, move your plant to a sunnier and windier location rather than resorting to continued chemical treatments.
Another ʻakoko pest (more common in irrigated or wetter landscapes) is the giant African snail (Lissachatina fulica), which will come out of its hiding place at night and girdle the stems or eat the leaves of ‘akoko; girdled stems eventually die. If this happens, and your ‘akoko is in a pot, try to solve the problem by moving it to a safer location. Also, closely inspect the container to make sure the snail(s) are not living inside. Refer to the Pests & Diseases page for other ways to deal with snails.
Uses
Ancient Hawaiian
There are about 17 endemic species of ‘akoko found in Hawai‘i, depending on which taxonomist you talk to. All possess a milky sap. According to Krauss [1993], the sap was used in the paint for canoe hulls. Under E. lorifolia, Hillebrand & Hillebrand [1888], page 396, state, "The tree is much used as firewood." Pukui & Elbert [1986] state that Euphorbia (Chamaesyce) multiformis leaves and buds were chewed to treat debility. This claim likely originates from Ka‘aiakamanu & Akina [1922], who recommended this practice for mothers and babies.
Note: The milky sap of all Euphorbia species can cause skin irritation, warts, and, despite the claims above, should not be ingested without medical supervision due to potential toxicity.
Modern
Special Features and Information
General
Euphorbiaceae is a large family with about 7,500 species within 300 genera, found on all the continents except Antarctica, with the greatest diversity in the tropics. Some well-known non-native relatives of ʻakoko are the Castor oil plant (Ricinus communis), kukui (Aleurites moluccana), poinsettia (Euphorbia pulcherrima), cassava (Manihot esculenta), and the Pará rubber tree (Hevea brasiliensis) from which we get latex [WikipediA;Euphorbiaceae].
There are currently (2026) 17 native species of Euphorbia in Hawai‘i — all endemic to the Islands. Several species are either vulnerable, rare, or endangered, and two varieties are considered to be extinct [Flora of the Hawaiian Islands]. They range in stature from very prostrate shrubs like Euphorbia degeneri to tall trees like Euphorbia haeleeleana and Euphorbia olowaluana [Wagner et al. 1990].
While not all the native Hawaiian Euphorbia species have been thoroughly investigated, a study by Pearcy & Troughton [1975] of 12 species (that did not include E. skottsbergii var. skottsbergii) found that they all appear to utilize C4 photosynthesis, an adaptation that enables greater water-use efficiency and improved growth in hot, dry environments when compared to the more common C3 photosynthesis seen in most plants. While most C4 plants are grasses or herbs, the native Hawaiian Euphorbia are among the few examples of woody plants — specifically trees like E. olowaluana — that possess the C4 photosynthetic pathway, which usually involves a specialized anatomy (i.e., Kranz) that can be challenging for tree growth.
In addition to the many endemic Euphorbia species, the only other member of Euphorbiaceae native to Hawai‘i is the endemic poʻolā (Claoxylon sandwicense) [Flora of the Hawaiian Islands].
Hawaiian Name
ʻAkoko comes from the Hawaiian word for blood, koko. This is likely a reference to the red, or blood-colored, seed capsules that look like drops of blood on many Hawaiian Euphorbia species [Krauss 1993, Neal 1965]. Alternatively, some believe the name comes from the observation that ‘akoko leaves, when damaged, often turn red, giving the appearance that the plant bleeds when it is injured.
Etymology
Euphorbia is named after Euphorbos, a Greek physician of King Juba II of Numidia and Mauretania (52–50 BC – 23 AD), who married the daughter of Anthony and Cleopatra [WikipediA; Euphorbia], and used the sap of a spurge for medicinal purposes [Gledhill 2008].
The former genus name, Chamaesyce, is derived from the ancient Greek words, χαμαί (khamaí), meaning “near the ground,” and συκῆ (sukê), meaning "fig-tree," perhaps referring to the low habit of most species and the fig-like appearance of the fruit capsules [Wiktionary;Chamaesyce].
The species name, skottsbergii, is in honor of Carl Johan Fredrik Skottsberg (1880–1963), a Swedish botanist and explorer who visited the Hawaiian Islands and elsewhere [Sherff 1936].
BPK