Haplostachys haplostachya
Lamiaceae or Mint family
Synonyms: Haplostachys grayana, Haplostachys grayana var. angustifolia, Haplostachys grayana var. leptostachya, Haplostachys haplostachya var. angustifolia, Haplostachys haplostachya var. leptostachya, Phyllostegia haplostachya, Phyllostegia haplostachya var. leptostachya, Phyllostegia leptostachys
Honohono
Natural Range & Environment
Haplostachys haplostachya was formerly known from barren ridges on Kauaʻi and sandy isthmus in Kula, Maui. Today (2026), it is extinct everywhere except Hawaiʻi Island [Wagner et al. 1990], where it is found in upper montane to subalpine areas at 1500–1800 m. (ca. 4921– 5906 ft.) [USFWS. 2022; Haplostachys haplostachya]. As of 2023, there were an estimated 12,358 wild individuals of Haplostachys haplostachya across six sites at Pōhakuloa Training Area (PTA), Hawaiʻi Island [USFWS. 2023; Haplostachys haplostachya].
Honohono is easy to grow and flower. Pictured above under cultivation are its habit, flowers, and dried fruit with seeds. Note the fruiting delissea behind the honohono in the first photo.
While the flowers are spectacular in themselves, the foliage is attractive enough to grow for it alone. The leaves have a velvety appearance and feel to them on the surface and underneath.
Honohono in the wild at Pōhakuloa, Hawaiʻi Island. Photographs courtesy of C.H. Lamoureux, J.K. Obata, and PTA Natural Resources Office (NRO) staff via G.D. Carr ©.
Three of the four extinct Haplostachys spp. as herbarium specimens: H. bryanii, H. linearifolia, and H. munroi. (H. truncata not pictured). I (Eickhoff) used a pen for scale (5.25 in; 13.3 cm). Photographed with permission from the Herbarium Pacificum, Bernice Pauahi Bishop Museum, Honolulu. See Special Features and Information-General for more information on these extinct Haplostachys.
Description
Honohono is a short-lived perennial herb that grows to a height of 5 feet (1.5 m). Like many Lamiaceae or mints, it has square stems.
The leaves can have a woolly or hairy texture, are simple and narrowly heart-shaped. The upper surfaces of the slightly fleshy leaves are wrinkled and covered with downy, straight, erect hairs. The lower leaf surfaces are densely covered with woolly hairs. Leaf margins are scalloped with shallowly rounded teeth.
The showy, stalked flowers are arranged along a terminal main axis. The main axis is 4 to 12 inches (1–3 dm) long with two two-lipped flowers at each node. The flowers are either pure white, or tinged with purple.
The mature fruit is dry, hard, and dark brown; the shape is obconical (cone-shaped with a pointed end) and three-angled.
Growth Requirements
General
Honohono are easy to grow in containers in media with very good drainage. Therefore, a very generous amount of black cinder should be added to the mix. I (Eickhoff) have used as much as half black cinder in the media mix. It requires very little water to thrive and grow to specimen plants. Despite their seemingly delicate appearance, honohono are sun-loving plants and should be provided with full sun for most of the day. I never tried to put any in the ground to see how they would do as landscape plants. Foliar feed plants monthly or apply small amounts of 8-8-8 fertilizer every six months.
To extend its lifespan by a few more years Kerin E. Lilleeng-Rosenberger [2005] suggests "do not allow the plant to bloom and make seeds." She continues, "To accomplish this, for the first couple of years, cut off any flower stalks that grow, and this will strengthen the plant." I (Eickhoff) have applied her method with the cultivated plant pictured above with very good results! Along with a good fertilizer regime, it produced a robust, not leggy, plant with an abundance of flowers and fruits with more mature seeds in about two years or less. The blooming period can extend beyond February–July [USFWS. 2023; Haplostachys haplostachya]. This is especially so if plants are grown from seed, in which case I have had continuous flowering for 6 months or more.
To prevent powdery mildew on leaves, be sure to provide good air movement. See Pests and Diseases.
Pests and Diseases
Honohono is occasionally attacked by mealybugs (sometimes going after its roots), scale insects, and spider mites. If watered too frequently, the plant's base or roots can become infected and rot. The leaves are susceptible to powdery mildew. Refer to the Pests & Diseases page for methods to control/eliminate these pests and fungi.
Uses
Ancient Hawaiian
We have found no record of it being used by early Hawaiians. Perhaps naming it hononono, they merely enjoyed the fragrant flowers as much as we do today.
Modern
Although the leaves of Haplostachys haplostachya are unscented, the flowers have a distinct fragrance. I (Eickhoff) have used the flowers and leaves in cut arrangements that remain fresh for several days. The buds will continue to bloom into flowers. I recommend changing the water in the holding container daily. (See the photos below)
Special Features and Information
General
The Mint family (Lamiaceae) is a large family with approximately 7,000 species within about 236 genera with a cosmopolitan distribution. Many of the species, such as basil (Ocimum basilicum), lavender (Lavandula spp.), oregano (Origanum vulgare), rosemary (Salvia rosmarinus), and thyme (Thymus vulgaris), are well known because of their aromatic properties and culinary uses [WikipediA;Lamiaceae].
Haplostachys is an endemic Hawaiian genus of one endangered and four extinct species. Here is a brief summary of the genus [Wagner et al. 1990]:
Haplostachys bryanii — Presumed extinct. Formerly occurring in low elevation, dry habitats on central to southwest Molokaʻi. Last collected in 1918 at Kalaeokalā‘au Flats.
Haplostachys haplostachya — Endangered. See Natural Range & Environment and Description above for status and description.
Haplostachys linearifolia — Presumed extinct. Known from dry shrubland and woodland on Molokaʻi (Mauna Loa, Kawela Gulch, Kamalō, and Pu‘ukolekole), and one collection from Wailuku, Maui. Last collected on Molokaʻi in 1928.
Haplostachys munroi — Presumed extinct. Formerly occurring on the west end of Lānaʻi (Ahupua‘a Ka‘ā and Paoma‘i). Last collected in 1935.
Haplostachys truncata — Presumed extinct. Known only from the type collected on Maui in 1851–1855. H. truncata apparently is closely related to H. linearifolia, but differs primarily in the truncate leaf bases and smaller calyx teeth.
In addition to five species of Haplostachys, other native Hawaiian members of Lamiaceae include: indigenous species such as ʻalaʻala wai nui wahine (Coleus australis), pakaha (Lepechinia hastata), and pōhinahina (Vitex rotundifolia); about 35 endemic extinct and extant species of Phyllostegia; and about 25 endemic extinct and extant species of Stenogyne [Flora of the Hawaiian Islands].
Hawai‘i's native Lamiaceae are often referred to as "mintless mints" because their leaves lack the minty smell or taste typically found in other members of Lamiaceae elsewhere, such as mint, perilla (shiso), sage and others, in addition to those mentioned previously. Still, there are a few native Hawaiian mints that have a sweet floral fragrance (e.g., Haplostachys) or a spicy leaf aroma (e.g., Vitex rotundifolia).
Hawaiian Name
The Hawaiian name Honohono sometimes translates to hohono meaning "bad smelling", as in an acrid odor, unpleasant body odor of perspiration [Hawaiian Dictionaries]. But the flowers actually emit a pleasant fragrance resembling some plumeria, pikake, or some orchids.
The name Honohono is also used for Wandering Jew or Dayflower (Commelina diffusa), Basket grass (Oplismenus hirtellus) [Flora of the Hawaiian Islands], and Honohono orchid (Dendrobium anosmum), a favorite orchid in gardens of Hawai‘i [Hawaiian Dictionaries].
Etymology
The endemic genus Haplostachys and the specific epithet haplostachya comes from the Greek words haplo, meaning single, and stachys, meaning spike, which refers to its flower arrangement where a single flower sits at each leaf axil [Wagner et al. 1990, Gledhill 2008].
DWE
