Euphorbia haeleeleana produce a type of inflorescence that either has only tiny male flowers (upper photograph courtesy of Flora of the Hawaiian Islands ©) or a single central female flower (lower photograph courtesy of Kenneth R. Wood (NTBG) CC BY-NC 4.0). These male and female inflorescences are produced on separate trees (i.e., the species is dioecious). These large round immature fruits will dry and then explode when fully ripe; note the milky sap emerging from the uppermost capsule (Photograph courtesy of Kenneth R. Wood (NTBG) CC BY-NC 4.0.). The large elliptic leaves of E. haeleeleana typically have a yellow to red midrib. Compare the somewhat odd growth of this juvenile cultivated E. haeleeleana to that of a mature wild tree growing in the Wai‘anae Mountains, O‘ahu. (Header photograph courtesy of Kenneth R. Wood (NTBG) CC BY-NC 4.0.)

Growth Requirements

General

    The jury is still out as to whether Euphorbia haeleeleana will find a place in Hawai‘i's landscapes. For the first several years, all my (Koebele) plants did quite well, often growing taller than me with even a few flowering and producing fruits. However, sometime before or around their tenth birthday, some injury or disease, either to their roots (unknown cause) or lower trunk (rot or chewing) caused them all to die. Other growers I have talked to describe similar experiences. Therefore, until we know more, my recommendation is to keep your Euphorbia in a container positioned well above the ground. Because this tree does not respect pot boundaries, you will need to repeatedly transfer your plant to larger and larger containers to avoid having its roots becoming distorted and potbound. If you wish to risk your plant in order to further our horticultural understanding of this species, I suggest planting your Euphorbia atop a mound of fresh cinder and placing a protective guard around its base. (Unfortunately, all my plantings were in clay-dominant soil and unprotected.) If your plant still dies, conduct an autopsy and send a sample to the University of Hawai‘i at Mānoa Agricultural Diagnostic Service Center to see if they can definitively determine why it died. Lastly, so we can improve the information provided on this webpage, we would love to hear from you about your experiences growing this amazing plant. Contact us at: EickhoffandKoebele@gmail.com. The following is some additional advice based on my past horticultural and field experiences.

    All the wild Euphorbia haeleeleana I've seen were growing in brightly lit locations (i.e., full sunlight for most of the day). Therefore, I have always selected planting sites with similar light conditions and the plants have grown well. All these sites were naturally watered locations (i.e., I did not irrigate) on the leeward side of O‘ahu where most of the rain falls during the winter months. During the wet season, the plants grew rapidly, adding 1 to 3 feet (30 to 91 cm) to their height each year. During the dry summer months, they would drop all or most of their leaves and go dormant. My guess is that if you lightly watered your Euphorbia during the dry season, it would grow more rapidly. I never fertilized my in-the-ground Euphorbia, while my smaller plants still in their pots received an application of granular balanced controlled-release fertilizer every six months. These naturally-watered Euphorbia began flowering after four to ten years, being 6 to 10 feet (1.8 to 3 m) tall. Of course, if your goal is to collect seeds, you'll need at least one female and one male plant in your landscape (and, unfortunately, I haven't discovered a way to sex the plants prior to flowering). And, you will need to bag the unripe fruits before they ripen and explode.  

Pests and Diseases

    Scale insects infrequently infest Euphorbia haeleeleana leaves, stems, and roots. Also, their thin bark is vulnerable to damage by chewing pests like rats and mice, snails and slugs, and cockroaches, particularly at the plant's base. Refer to the Pests & Diseases page for ways to deal with each of these pests. As described above, an unknown soil pest or disease, as well as a type of basal stem rot was responsible for the death of all my plants. 

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 Euphorbia haeleeleana in Hawai‘i 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. haeleeleana) 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

    Most literature sources do not ascribe an ancient Hawaiian name to Euphorbia haeleeleana, although a few refer to this species as ‘akoko or ‘akoko tree (e.g., ECOS). Given the morphological differences between E. haeleeleana and the majority of the other Hawaiian Euphorbia (which were all previously placed in a different genus, Chamaesyce) such as much larger leaves and fruits, we (currently) just don't know if Hawaiians considered E. haeleeleana just another ‘akoko. Therefore, we have adopted the majority opinion that the ancient Hawaiian name for E. haeleeleana is currently unknown.

    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 species name, haeleeleana, is a Latinization of Haeleʻele Valley on the northwestern coast of Kauaʻi, part of the species' native habitat [Encyclopedia.com].