Sabdariffa brackenridgei
(formerly Hibiscus brackenridgei)
Malvaceae or Mallow family
There are currently three subspecies that we described below:
S. brackenridgei subsp. brackenridgei
S. brackenridgei subsp. mokuleiana
S. brackenridgei subsp. molokaiana
Ma‘o hau hele
Aloalo
Brackenridge's rosemallow
Native yellow hibiscus
Natural Range & Environment
Sabdariffa brackenridgei is known from Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui, Hawai‘i Island, and possibly Kaho‘olawe. Currently, there are two extant subspecies: brackenridgei and mokuleiana. Plants known as subspecies molokaiana on Moloka‘i (and once thought to exist on O‘ahu) are extirpated; however, see below. At the time the species (and subspecies) was federally listed as endangered, it was already extirpated on Kaua‘i, Kaho‘olawe, and Moloka‘i. Sabdariffa brackenridgei subsp. brackenridgei is extant on Lāna‘i, Maui, and Hawai‘i Island. On O‘ahu, Sabdariffa brackenridgei subsp. mokuleiana occurs in the Wai‘anae mountains at Kaumoku Nui, Kawaiū, Palikea, Kihakapu, Kaimuhole Gulch, and Mākua Valley. On Moloka‘i, Sabdariffa brackenridgei subsp. molokaiana was last collected in 1920 from Lā‘au Point.
On Kaua‘i before its extirpation, Sabdariffa brackenridgei (subspecies uncertain) was reportedly collected in Lihue and Olokele Canyon. On O‘ahu, S. brackenridgei subsp. mokuleiana occurs on slopes, cliffs, and arid ledges in lowland dry forests and shrublands at 24 to 490 m (79 to 1,607 ft). On Moloka‘i, S. brackenridgei subsp. molokaiana, before its extirpation, occurred on slopes in lowland dry forests and shrublands at 11 to 467 m (36 to 1,531 ft). On Lāna‘i, S. brackenridgei subsp. brackenridgei has been found along Keomuku Road, inside the Kānepu‘u Preserve, and at Ka‘ena Point. On Maui, S. brackenridgei subsp. brackenridgei occurs in lowland dry forests sometimes with Erythrina sandwicensis (wiliwili) as the dominant tree at 43 to 771 m (141 to 2,530 ft), while on Hawai‘i Island, it occurs in Acacia koa (koa) lowland mesic forests at 457 to 793 m (1,500 to 2,600 ft). [USFWS;ECOS].
A Mākua Valley, O‘ahu, population of Sabdariffa brackenridgei was discovered in 2000 by Joel Lau which is morphologically similar to preserved specimens of S. brackenridgei subsp. molokaiana, known only from West Molokaʻi and now considered extinct there. Later genetic analysis by Huppman (2013) confirmed that this population was genetically distinct from the other O‘ahu populations. However, Huppman did not determine if it was genetically the same as the extinct molokaiana subspecies. Currently, as far as we can tell from our research, USFWS and the Army Natural Resources Program, O‘ahu (ANRPO; formerly OANRP), who manage all the O‘ahu ma‘o hau hele populations, are maintaining this Mākua population as a separate genetic entity under the subspecies mokuleiana classification.
Regarding this Mākua population, Hawaiʻi botanist Joel Lau notes: "Plants discovered in Mākua Valley in the northwestern Waiʻanae Mountains, Oʻahu, in 2000 and a few years later in Keaʻau Valley are similar to the plants of H. brackenridgei subsp. molokaiana from West Molokaʻi. The Molokaʻi plants, which are not known to be extant, were apparently more prostrate than the Oʻahu plants judging from a photograph taken of a Molokaʻi plant by Joseph Rock."
The three ma‘o hau hele subspecies not only have morphological differences between them, but also variations within each subspecies, which can make proper identification difficult. Here we have: two flower variants of subspecies brackenridgei, the flower and super-prickly flower buds of subspecies mokuleiana, and the flower and mature cultivated shrub of the Mākua variety (which some consider to be equivalent to the extinct subspecies molokaiana from Moloka‘i).
Description
Ma‘o hau hele, like many Malvaceae, is a polymorphic species (see photographs above) that varies in stature, pubescence, and leaf and flower characteristics, so much so that taxonomists have divided it into three subspecies. Even within the three subspecies, we see significant morphological variation.
Ma‘o hau hele, in our experience, do not live very long in cultivation before showing signs of senescence, with ten years being about the maximum lifespan and five or fewer being common. Often, senescence starts with leaf loss and the production of smaller and smaller leaves. Following this, branches begin to die or break at their base, almost like an aging rose with its petals slowly unfolding and withering. Occasionally, one of these aged branches will root, become reinvigorated, and grow into a new clone plant. It is this rebirth behavior that some have pointed to as the origin of the plant's Hawaiian name, ma‘o hau hele, or "the traveling green hau."
In cultivation, the subspecies mokuleiana can grow into a small tree (up to about 15 ft [4.6 m]) while the other two subspecies are shrubs, often wider than they are tall. All ma‘o hau hele have gray bark and soft white wood.
Ma‘o hau hele leaves are green to grayish-green, two to six inches (5 to 15 cm) long and wide, and have a slightly rough, sandpaper-like feel, although there are also plants with smooth hairless leaves [Robert Hobdy, per. comm.]. The serrated to toothed leaves are shallow to deeply 3-lobed, 5-lobed, or 7-lobed, sometimes having partially pink to maroon veins.
The perfect (bisexual) flowers of ma‘o hau hele are bright yellow with varying amounts of red to maroon in the flower's throat, with the subspecies brackenridgei displaying the most variation in flower morphology. Wild ma‘o hau hele typically have an extended blooming period in the winter to spring, while cultivated plants can be more sporadic bloomers. Pollinated flowers develop into five-chambered dry tan to brown capsules with each chamber holding a few fuzzy brown seeds.
Ma‘o hau hele stems, flower sepals, and fruits (capsules) vary in the density and rigidity of the prickles or spines on them. Subspecies mokuleiana has the most annoying defenses in this regard, while some forms of subspecies brackenridgei are nearly prickle/spine-free. Donning a pair of gloves before collecting ma‘o hau hele seeds is always a smart move.
Growth Requirements
General
Ma‘o hau hele is one of the easiest native hibiscus to grow and maintain in a landscape — provided you follow two simple rules: one, lots of sun, and two, very little water. Use it as a landscape accent, screen, or to create an informal (i.e., lightly pruned) hedge. It can also be kept in a container.
Plant your maʻo hau hele along the south- or west-facing side of a building so it receives sunlight for all or most of the day. For the first month or so, water your new plant regularly once or twice a week until you see new growth. Then, cut back dramatically on watering to once a month or less; container plants will require more frequent watering (i.e., once or twice a week). Do not overwater your maʻo hau hele since this will cause root or base-stem rot (and death) or powdery mildew on its leaves. Ma‘o hau hele is tolerant of extreme heat and drought, and will grow in lava/cinder, clay, or organic-dominant soils, provided they remain surface dry most of the time and drain well; we have not grown ma‘o hau hele in sand or coralline soil. Waterlogged soils will quickly result in root and base-stem rot.
Ma‘o hau hele often have shallow roots or grow top-heavy, causing them to uproot and topple over in strong winds. You can prevent this from happening by either protecting it with surrounding plants or structures (e.g., a rock wall) or by regular hand-pruning to reduce its height and increase the airflow through its branches.
Ma‘o hau hele in the ground generally do not require fertilizer. However, if you do fertilize, use a fertilizer with minor elements and single-digit concentrations of the major elements (e.g., 2:1:3;N:P:K). Prune your plant after flowering or to encourage branching. However, don't prune when your maʻo hau hele is flowering, normally during the winter and spring.
Ma‘o hau hele in cultivation typically grow very quickly, and it's not unusual to have a plant that was planted in the summer producing flowers the following spring. Unfortunately, as described above, cultivated ma‘o hau hele don't seem to live very long, and if you can keep one alive past five years, you're doing an exceptional job. With this in mind, be sure to collect seeds or cuttings from your plant before it dies. Both are easy to propagate (see Native Hawaiian Garden for details on how).
Pests and Diseases
Chinese rose beetles love ma‘o hau hele. And, while we’ve never seen the beetles kill a plant, they do make it unsightly with all the hole-ridden leaves. One creative way to minimize beetle damage is to plant your ma‘o hau hele near an overhead outdoor lamp. Turn the lamp on at sunset and leave it on until about midnight. The beetles will avoid the light, and, with luck, your ma‘o hau hele. Mealybugs often attack young plants as well as the stem-tips and flower buds of older plants. Aphids, spider mites, and whiteflies also, sometimes become a problem. Ma‘o hau hele is susceptible to root-knot nematodes, so avoid planting it in any questionable locations. Refer to the Pests & Diseases page for ways to deal with each of the above-mentioned pests. As mentioned above, overwatering can cause powdery mildew on leaves and root or base-stem rot (leading to death).
Uses
Ancient Hawaiian
Hawaiians planted native hibiscus near homes for ornamental use [Handy & Handy 1972] which might help explain the very confusing distribution of the three ma‘o hau hele subspecies. The bark of aloalo (the generic name for native hibiscus species) was likely used to make cordage (inferior to hau), but supportive written accounts are scarce. For example, Krauss 1993 mentions "hibiscus."
Modern
Friend and expert kapa-maker, Dalani Tanahy, collects ma‘o hau hele flowers to make a dye for her kapa. I (Koebele) don’t know if this is only a modern practice, but I suspect not.
Special Features and Information
General
The large Mallow family, Malvaceae, contains about 4,200 species, with notables such as okra, cacao, durian, baobab, kenaf, and cotton [WikipediA;Malvaceae]. There are currently seven native hibiscus recognized in the Hawaiian Islands, with all but two considered endemic [Flora of the Hawaiian Islands].
When a "red hibiscus" was designated the official flower of the Territory of Hawaiʻi by the Legislature in 1923, it was not specified to any particular hibiscus species or variety, which led to some confusion with many considering either the native red (Hibiscus kokio) or the Chinese red hibiscus (Hibiscus rosa-sinensis) as the Hawaiʻi State flower. In 1988, however, the Hawaiʻi State Legislature resolved the issue by declaring our native yellow hibiscus or maʻo hau hele as the official flower of the State of Hawaiʻi [Kepler 1998]. Unfortunately, photographs of a yellow form of the Chinese hibiscus are still frequently used online and elsewhere to improperly illustrate the Hawaiʻi State flower.
Maʻo hau hele was the first endangered native Hawaiian plant to be legally sold. This happened in 1998 at the Harold Lyon Arboretum's Plant Sale at the Neal Blaisdell Center, shortly after the State's endangered species law was amended.
Hawaiian Name
According to Pukui & Elbert (1986), maʻo hau hele translates as “the green traveling hau.” This never made much sense to me (Koebele) until, on a trip to Kaua‘i, Rick Barbosa, co-owner of Hui Ku Maoli Ola, provided me with an explanation. Ma‘o hau hele are related to the important long-lived Hawaiian tree hau (Talipariti titiaceum, syn: Hibiscus tiliaceus) but are short-lived plants. When they die, their branches often spread apart and fall to the ground like the petals of an aging rose. Occasionally, one of these old branches will root and grow into a new plant. This plant may then die, its branches again spreading apart, rooting, and repeating the rebirth. Such a phenomenon, over time, could be seen as a plant that moves or travels across the ground.
A second interpretation of the name recognizes that both ma‘o, our native cotton, and ma‘o hau hele have large, bright yellow flowers. And, both hau and ma‘o hau hele have a stringy bark that, in ancient times, Hawaiians made into cord. Hele can be translated as “to go,” but it can also mean “similar.” Therefore, as an alternative to "the green traveling hau," perhaps, the name means: the plant that has a yellow flower similar to ma‘o and bark similar to hau.
Aloalo is the generalized name Hawaiians use for all hibiscus species.
Etymology
Sabdariffa has an uncertain origin. It may have come from a West Indian vernacular name for a local hibiscus [Gledhill 2008], which, in turn, might have come from either a Jamaican word or a Turkish word [Wiktionary;sabdariffa].
The former genus name, Hibiscus, is the Latinized form of the Greek word ibiskoj or hibiskos from Virgil, hibiscum, for the marshmallow plant, Althaea officinalis [Gledhill 2008].
The species and subspecies name, brackenridgei, is named after William Dunlop Brackenridge (1810–1893), a Scottish-American horticulturist and assistant botanist on the United States Exploring Expedition (1838–1842) led by C. Wilkes, which visited the Hawaiian Islands [JSTOR;Brackenridge].
The subspecies, mokuleiana, is named for Mokulēʻia, an area in the northern Waiʻanae Mountains of Oʻahu where this subspecies is found. The subspecies, molokaiana, is named after the island of its discovery, Molokaʻi, where, ironically, it is now extinct.
BPK