Bobea sandwicensis flowers are usually unisexual (male or female) with a very prominent calyx (all the sepals of a flower) almost looking like a flower itself after the corolla (all the petals of a flower) has fallen away. ʻAhakea berries are dark purple to black when ripe, with each containing a few wedge-shaped seeds (Photograph courtesy of J.K. Obata via G.D. Carr ©.). The petiole and major veins of B. sandwicensis leaves are often red or yellow.

Growth Requirements

General

    The most attractive and healthy ʻahakea I (Koebele) have ever seen was a three-foot-tall plant in a 25-gallon pot under full sunlight in a nursery; I wish I had taken a picture. That ʻahakea was later planted in the ground where it died after a year or so. Nearly all my own ʻahakea have suffered a similar fate, dying after I planted them in the ground, either because they did not receive enough water (within a restoration site), or because, I think, some unknown and deadly soil microbe killed them. I say nearly, because there is one eight-year-old ʻahakea in the ground that was still alive the last time I saw it (2024). This ʻahakea, planted on a slope of clay-dominant soil, has slowly grown to be about three feet tall. Throughout its life, it has struggled at the site, receiving lots of direct sunlight during the hot summer and only a little during the winter months. It's never been attractive, and is rarely free of sap-sucking pests like scale insects and whiteflies. Still, it has persisted. I share all this history as a preface to my recommendation: If you want to grow — and keep — ʻahakea for the long term, your best bet is to keep it in a container where you can give it everything it needs and best protect it from its numerous pests and diseases.

    A containerized ʻahakea does best in a site with full sunlight for all or most of the day, provided it is also well watered. Water your ʻahakea enough to keep the below-surface (1 to 2 inches [2.5 to 5 cm) media moist while the surface media remains dry most of the time. The media should have excellent drainage; I typically used a 50:50 mix of sphagnum peat moss and black cinders.

    Fertilize your ʻahakea regularly with either a controlled-release fertilizer with minor elements every six months, or by spraying your plant with an organic or inorganic water-soluble fertilizer diluted to ⅓ to ½ the recommended strength. Don't be disappointed if your ʻahakea grows slowly (6 to 12 inches [15 to 30 cm] per year); this seems to be normal. Fortunately, ʻahakea begin flowering when they are quite young and small, sometimes less than a foot [30 cm] tall! If you are able, try to grow several plants so you have at least one female and one male ʻahakea that can then produce viable seeds to give away to all your friends.   

    Keep your containerized ʻahakea off the ground to prevent harmful microbes, nematodes, and insects from easily entering the pot and causing problems. As your ʻahakea grows larger, transfer it to larger and larger pots. I would typically start with a half-gallon pot for an ʻahakea less than two feet (61 cm) tall, and move up to a two gallon pot when it grew beyond two feet. After that, try doubling the pot size for every one to two feet of new growth. 

Pests and Diseases

    Unfortunately, even containerized ʻahakea are attacked by several serious pests. Black twig borers can become a real problem, particularly if your plant is in a windless location. Fortunately, ʻahakea begin to branch early and profusely in sunny sites, lessening the probability the borer attacks your small tree's main trunk. However, even if it does, don't despair — yet. Act quickly, and prune away all the branches with borer holes, then continue to water your plant and wait. Often, these little trees will recover with new shoots from even a devastating attack. Refer to the Pests & Diseases page for other ways to deal with black twig borers.

    Sap-sucking insects are also a common pest of ʻahakea, particularly scale insects, thrips, and whiteflies. ‘Ahakea are also susceptible to root mealybugs that can quickly kill them. Inspect the tree’s base and just under the media's surface regularly for mealybugs, or look for the ants that often tend and protect them. Refer to the Pests & Diseases page for other ways to deal with these pests.

    Lastly, I am fairly certain I have had ‘ahakea die from harmful microbes in the soil, but never while they were still in a pot. Hopefully, your luck will be the same. However, if your containerized ‘ahakea dies suddenly without cause, conduct an autopsy of the roots to see if there is any damage or rot. Then, if your able and willing, start again with a new (or sterilized) pot and brand-new media. In my opinion, growing this attractive and culturally-important plant is worth a second or third try.

Special Features and Information

General

    Rubiaceae is a large family with about 14,200 species within about 615 genera. This family of trees, shrubs, lianas, and herbs has a cosmopolitan distribution with the greatest species diversity in the tropics and subtropics. Plants in the family all have simple leaves with stipules located between the petioles of the oppositely-positioned leaves (on a stem) [WikipediA;Rubiaceae]. 

    The genus Bobea is endemic to the Hawaiian Islands and contains four species: 

• Bobea brevipes — endemic to Kaua‘i and O‘ahu.

• Bobea elatior — endemic to all the main Hawaiian Islands except Ni‘ihau and Kaho‘olawe.

• Bobea sandwicensis — endemic to O‘ahu, Moloka‘i, Lāna‘i, and Maui.

• Bobea timonioides — endemic to Kaua‘i, O‘ahu, Maui, and Hawai‘i Island [Flora of the Hawaiian Islands].

Hawaiian Name

     According to Hillebrand [1888], all the Bobea species are called "Ahakea by the natives and in the forests can be recognized from a distance by their pale green foliage."

Etymology

    Bobea honors Jean-Baptiste Bobe-Moreau (1761–1849), a French doctor and naval pharmacist in Rochefort, Charente-Maritime who published a catalog of the plants in that district, and founded a directory of eponymic plant names [WikipediA; List of Plant Genera Named for People (A-C)].  

    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].