Thespesia populnea
Malvaceae or Mallow family
Synonyms: Hibiscus bacciferus, Hibiscus populneus
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Milo
In Hawai‘i, sometimes called the Indian tulip tree, Pacific rosewood, or Portia tree. Outside Hawai‘i, Thespesia populnea has numerous names. See Hawaiian Name below.
Natural Range & Environment
Thespesia populnea is native to tropical and subtropical coastal regions surrounding the Indian Ocean (East Africa to India and Southeastern Asia) and the Western Pacific Ocean (Papua New Guinea and Australia). In the Pacific Ocean, the species is found growing on many islands [Friday & Okano 2006; Kew: Plants of the World Online]. However, it's difficult to determine if this is because of natural or human-assisted dispersion. Thespesia populnea has also been introduced into Central and East Africa and the tropics and subtropics of the Americas and Caribbean and has naturalized in many of these regions [Kew: Plants of the World Online].
In Hawai‘i, Thespesia populnea is found "naturally" on all the main Islands except Kaho‘olawe [Flora of the Hawaiian Islands]. Planted and wild plants are common in coastal areas from near sea level to 275 m (902 ft) [Plants of Hawai‘i], including areas near streams and in tidal flats that experience occasional tidal water inundation. Additionally, because of plantings, it can now be seen on Kaho‘olawe [Starr; Wikimedia Commons] and some of the other Hawaiian Islands such as Midway Atoll (Pihemanu) [Plants of Hawai‘i].
While scholars generally agree that early Polynesian explorers brought Thespesia populnea (most likely its seeds [Abbott 1992]) with them to Hawai‘i, there is disagreement as to whether the species was already present in the Islands (i.e., was indigenous) [Wagner et al. 1990; Friday & Okano 2006]. Botanists who think T. populnea is indigenous to the Hawaiian Islands point to two facts: (1) its fruits and seeds float in seawater and can remain viable for many months [Little & Skolmen 1989; Nakanishi 1988], and (2) it is a coastal plant that grows well in the salty soils (e.g., sand, silt, and rocks), places where its seeds were likely to wash up after a long voyage to the Islands. Botanists who think T. populnea is not indigenous to Hawai‘i point out that (1) no deep fossil (i.e., pre-human) evidence such as pollen has been found (so far) in the Islands [Burney 2011], and (2) Polynesians value milo for both its practical uses and spiritual significance [te māra reo; the language garden], making human transport to Hawai‘i the less presumptuous explanation.
Milo flowers, with their center-red throats (photograph courtesy of Krzysztof Ziarnek CC BY-SA 4.0), only last a day, turning from yellow to pinkish-purple as they age (photograph courtesy of Wendy Cutler CC BY 2.0). The fleshy green golfball-sized fruits of milo become dry and brown to black as they ripen (photograph courtesy of Steve K CC BY-NC 4.0), with each capsule containing a handful of fuzzy seeds (photograph courtesy of hola_lola CC BY-NC 4.0). On the coastline, it's not unusual to see both milo seedlings (photograph courtesy of atcgnyc CC BY-NC 4.0) and kou (Cordia subcordata) seedlings popping up between the rocks or from the sand. However, while milo seed leaves are smooth, the seed leaves of kou are ruffled (see Cordia subcordata for photograph). The bark of large milo trees is often deeply furrowed (photograph courtesy of Wendy Cutler CC BY 2.0).
Milo trees come in many shapes and sizes depending upon the environment they find themselves in. Here are just five examples: wind-pruned shrubs very near the ocean (photograph courtesy of Forest & Kim Starr CC BY 3.0 US); a windswept tree also near the ocean (photograph courtesy of Forest & Kim Starr CC BY 3.0); a young and very broad tree growing in fertile inland soil; a massive older tree in an irrigated beach park (photograph courtesy of Forest & Kim Starr CC BY 3.0); and a miniature tree confined to a bonsai pot (photograph courtesy of Biswarup Ganguly CC BY 3.0).
Description
Thespesia populnea is most often a small to medium-sized tree, 6 to 10 m (20 to 33 ft) in height [Friday & Okano 2006], frequently with a crown of crowded horizontal branches as wide or wider than the tree is tall. However, in some areas, milo is pruned by strong persistent winds into a shrub-like shape, while in other more sheltered sites it can grow over decades into a large tree (up to 20 m [66 ft]) [Wagner et al. 1990]. Milo rarely have a single straight trunk and more commonly have two or more crooked main trunks/branches. Its bark is gray and smooth when young, becoming darker and deeply fissured on large trunks and branches as it ages. Milo has beautiful reddish brown to dark brown heartwood and light brown to cream-colored sapwood. The wood is a favorite of both ancient and modern woodworkers because it is dense but easy to work, very durable and resistant to bugs, and only slightly shrinks as it dries. Freshly cut wood has a spicy fragrance, but this disappears as the wood ages [Friday & Okano 2006].
Milo has glossy heart-shaped to elongated heart-shaped leaves about 6 inches [15 cm] long with prominent major veins. Old leaves turn yellow before falling. People sometimes confuse milo and hau (Talipariti tiliaceum), particularly when there are no flowers or fruits to examine. However, you can always tell them apart by looking at their leaves: the underside of a milo leaf is smooth and hairless, while the underside of a hau leaf is fuzzy (see photograph).
The underside of a milo leaf (left) is smooth and hairless, while the underside of a hau leaf is fuzzy (photograph courtesy of M5tama CC BY-SA 4.0).
Milo produces perfect (bisexual) hibiscus-like flowers that open and close on the same day. Fresh flowers have five overlapping yellow petals, each with a marron spot at their inner base. As the flower ages and closes, the petals turn pink, purple, or dark red (see photograph above). Flowering is continuous to sporadic year-round. Pollinated flowers develop into fleshy, round (slightly flattened top to bottom) green fruits that ripen into leathery and then brittle, dry, woody, or papery brown to black capsules, usually with five chambers. Within each chamber are a few brown, hairy, angular seeds, each about 1 cm (0.4 in) long (see photograph above). Both fruits and seeds float in water.
Growth Requirements
General
Milo is an attractive, easy-to-grow shade tree or screen for sunny coastal and lowland locations and does poorly in constantly shaded or cloudy upland sites. Like kou (Cordia subcordata), it seems to prefer neutral to alkaline soils (e.g., sandy or calcareous coastal soils) but will also grow in clay, lava/cinder, or organic-dominant soils, although highly acidic soils should be avoided [Friday & Okano 2006]. Somewhat surprisingly, since you don’t see these often in Hawai‘i, milo can be kept as a miniature tree, bonsai style (see photograph above). Vic The Fig Guy has a great YouTube video on how to prune and train your bonsai milo.
When initially planted, water your milo regularly (i.e., once or twice a week) until it has established its root system and is visibly growing (typically after a couple of months). Milo will put down a deep taproot in soils that permit penetration, allowing it to endure long periods of drought. In rocky soils that cannot be penetrated or in soils that are occasionally flooded, milo develops a shallow root system that spreads along the surface. After your milo's roots are established, decrease your watering to once a month or possibly not at all, depending on the rainfall and water table level at the site; your milo will "tell" you if it needs more watering with wilted or dropped leaves. Milo is adapted to both dry habitats and temporarily waterlogged places such as tidal flats. However, it’s best if you avoid planting your milo in a space that consistently pools water after a rain because of possible root pathogens (see Pests and Diseases below).
Milo can tolerate extreme heat and moderate drought and winds; trees with a deep taproot can tolerate extreme drought. Several can be planted as a windbreak or to stabilize the soil in high-erosion areas. However, milo will grow tilted or be extremely short (i.e., shrub-like) in locations with very strong winds. Milo can survive in saline soils and tolerate salt spray, but heavy or persistent spray will eventually “burn” its leaves.
Young milo grow quickly under optimum conditions (e.g., a sunny, warm site with sandy soil and moderate soil moisture), increasing in height and width by about 3 feet (1 m) per year. However, after several years in the ground, expect this growth rate to slow as the tree's trunk and branches increase in girth. If you are growing milo for timber/woodworking, be prepared to wait decades until you can harvest sizable wood pieces. Trees can begin flowering after only one to two years [Friday & Okano 2006] and, once flowering, rarely take a break. If your milo grows slowly under what you think are perfect conditions, try applying a controlled-release fertilizer every six months or use a foliar fertilizer diluted to ⅓ to ¼ the recommended strength every couple of months. Containerized milo should be fertilized regularly.
Milo trees rarely grow straight and begin branching early near their base. Therefore, plan on regularly pruning your tree to establish and maintain a desired shape. However, because milo recovers slowly after a pruning, it’s best to be selective and limit your pruning to a few branches per pruning episode.
Like kou (Cordia subcordata), mature milo produce lots and lots of fruits, which can become a problem. While milo fruits don’t pose the same safety hazard as kou fruits, they do tend to create a messy understory. Therefore, avoid planting milo near sidewalks, driveways, etc., unless you’re okay with regularly sweeping up and discarding the plentiful fruits and seeds. Planted in the middle of a sandy or grassy park or lawn, the fruits and seeds tend to disappear but may also begin sprouting (if provided enough rain or irrigation), which will require regular removal if you don't want a forest of milo seedlings and saplings.
Pests and Diseases
To date (2026), we have not encountered any pests or diseases on milo. However, Friday & Okano [2006] note that milo is susceptible to a fungal leaf spot (Lophodermium sp.) and a fungal root and stem rot caused by Phellinus noxius in Hawai‘i; P. noxius causes a brown to black crust near the tree's base. For the leaf spot, try reducing the humidity (e.g., by reduced watering) and increasing the air flow around your milo (e.g., by pruning) and disposing of all infected leaves, including those that have fallen to the ground; do not compost the leaves. Spraying the entire plant with a fungicide such as one containing copper may also help. Unfortunately, Phellinus noxius is difficult to impossible to cure, and, therefore, the best solution is to remove and completely destroy the entire plant (including its complete root system) to stop the fungus from spreading to nearby plants. Should you encounter other pests or diseases, refer to the Pest & Diseases page.
Uses
Ancient Hawaiian
Krauss [197–; 1993] provides the most comprehensive account of the many ancient uses of milo, with many of these supported by the writings of Malo [1898/1903], Buck [2024 reprint of 1957 book], Neal [1965], Lamb [1981], Abbott [1992], and others.
Milo was planted around houses as a shade tree but had many other uses as well. Most important was its wood, second only to kou (Cordia subcordata) for making ‘umeke (bowls) and pā (platters). These were used primarily (but not exclusively) for storing or serving food because the wood did not impart an unpleasant taste to the food like other woods, such as that of the native koa (Acacia koa), which was also often used to make calabashes. Abbott [1992] also reports discovering a waʻa (canoe) made from milo.
The inner bark of milo was used for its fibers (e.g., to make cordage) but was considered somewhat inferior to hau (Talipariti tiliaceum). The young leaves were reportedly eaten. According to McDonald & Weissich [2003], the flowers were/are used to make lei, and the fruits were/are used to produce a dye or paint (see photographs below). Krauss [197–] also states, "Tannin, dye, medicine, oil, and gum were obtained from plant parts," but does not elaborate on aspects of this statement (e.g., medicine).
Modern
Today, milo flowers [McDonald & Weissich 2003] as well as seeds [Ide 2000] are occasionally strung into lei. Milo fruits are also still used to make different colored paints and dyes to stain traditional kapa or modern fabrics [Kapa Curious]. However, it is the use of milo wood by woodworkers that has endured for centuries. Today, craftpersons make both traditional, musical, and artistic pieces from the easy-to-work but durable wood (see examples below) [Friday & Okano 2006]. In other parts of the world, Thespesia populnea is used in many ways not documented for ancient Hawaiians (see Useful Tropical Plants for a rather comprehensive listing).
Two of the many ancient uses of milo that have continued into the present are woodworking and making dyes from milo fruit. Above are two modern woodworking examples: an ‛umeke lū‛au hand-turned by master woodworker William J. Keb (1937–2023) (photograph courtesy of Hankster333 Public Domain) and a wooden papamū and figure carved by David Young (photograph courtesy of J.B. Friday ©). Depending on the condition and preparation of a milo fruit (see Kapa Curious for details), it's possible to make different colored paints and dyes to stain traditional kapa or modern fabrics (photograph of oozing fruit sap and fruits with dyed kapa courtesy of Kapa Curious ©).
Special Features and Information
General
Milo is a relative of the more familiar hibiscus, both belonging to the Mallow family (Malvaceae), which contains about 4,225 species within 243 genera. Family members include herbs, shrubs, and trees found worldwide, but most commonly in the tropics. Some of the more economically important species include cotton (Gossypium spp.), cacao (Theobroma cacao), linden (Tilia spp.), durian (Durio spp.), Hibiscus, and okra (Abelmoschus esculentus) [Britannica; Malvaceae].
Malvaceae is one of the more common plant families in Hawai‘i, with native members in the genera Abutilon, Gossypium, Hibiscadelphus, Hibiscus, Kokia, Sabdariffa, Sida, Talipariti, Thespesia, and Waltheria [Flora of the Hawaiian Islands].
There are about 14 species in the genus Thespesia distributed from the South Pacific through Asia, Africa, and the Caribbean [WikipediA; Thespesia]. Thespesia populnea is the only species found in Hawai‘i [Flora of the Hawaiian Islands].
In Tahiti, Captain Cook reported that Thespesia populnea was regarded as a sacred tree that was planted around places of worship [Wagner et al. 1990]. Seemingly, elites in Hawai‘i also favored milo, and the house of King Kamehameha I in Waikīkī was surrounded by the trees [Neal 1965; Krauss 197–]. The statement — "Milo was considered a sacred tree, with its use prohibited to commoners. The house of King Kamehameha I in Waikīkī was surrounded by Milo trees" — is a widely circulated piece of Hawaiian historical lore frequently propagated in local blurbs and social media posts. It is likely a misinterpretation of the publications by ethnobotanist Dr. W. Arthur Whistler. Rather, Whistler emphasized the practical, everyday uses of Thespesia populnea by Polynesians throughout the Pacific. The restriction regarding commoners is most likely a reference to a specific local Hawaiian kapu (taboo) surrounding the personal property or grounds of aliʻi (high chiefs), such as King Kamehameha I's private milo grove in Waikīkī, rather than a sweeping rule regarding all milo.
Thespesia populnea was one of the plants listed as an emergency food for World War II servicemen in a manual titled Emergency Food Plants and Poisonous Plants of the Islands of the Pacific, published by the War Department. The manual states its purpose “is to aid the individual who becomes separated from his unit…so that this individual can live off the land.” It briefly identifies the plant and where it can be found and then states that "leaves may be eaten raw or cooked, as well as the flower buds and the flowers," but that the "fruits are not edible" [Merrill 1943].
Hawaiian Name
Milo and some of its reflexes (e.g., Miro) are considered to be a proto-Eastern Oceanic or proto-Polynesian word used by ancient Austronesian explorers for Thespesia populnea as they explored and migrated throughout the Pacific, replacing the earlier name for this plant, banaRo (and its reflexes), still used in some parts of the world [te māra reo; the language garden].
In addition to being the Hawaiian name for this species, Milo also means "Curl; to curl, twist, as sennit strands; to whirl, as water; to spin, as a tale; abortion" [Pukui & Elbert 1986].
Because of its wide geographic range, Thespesia populnea has numerous indigenous and common names outside Hawai‘i. Friday & Okano [2006] provide a fairly comprehensive list of these many names.
Etymology
Thespesia is derived from the Greek word, thespesios, meaning "divine," referring to T. populnea, which was collected in Tahiti by Captain Cook's expedition in 1769 and was reported to be a sacred tree that was planted around places of worship [Wagner et al. 1990]. The species name, populnea, is derived from the Latin name, populus, for a poplar tree and means "poplar-like" [Gledhill 2008], likely referring to the leaves of this species resembling those of some poplar (Populus spp.) species.
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