Native Plants of Hawai‘i - Pipturus albidus

Pipturus albidus

Urticaceae or Nettle family

Synonyms: Boehmeria albida, Perlarius albidus, Pipturus albidus var. gaudichaudianus, Pipturus albidus var. meyenianus, Pipturus brighamii, Pipturus brighamii f. kohalae, Pipturus eriocarpus, Pipturus gaudichaudianus, Pipturus gaudichaudianus var. asperrimus, Pipturus gaudichaudianus var. hualalaiensis, Pipturus hawaiiensis, Pipturus hawaiiensis var. eriocarpus, Pipturus hawaiiensis var. integrifolius, Pipturus hawaiiensis subsp. molokaiensis, Pipturus hawaiiensis var. molokaiensis, Pipturus helleri, Pipturus oahuensis, Pipturus pachyphyllus, Pipturus pterocarpus, Pipturus rockii, Pipturus skottsbergii, Pipturus taitensis, Pipturus taitensis var. gaudichaudii

Māmaki

Māmake,

Waimea (Kaua‘i)

Waimea pipturus

Natural Range & Environment

Pipturus albidus is endemic to all the main Hawaiian Islands except for Ni‘ihau and Kahoʻolawe. It is scattered to common in mesic to wet forests from about 70 to 1,870 m (230 to 6,135 ft) [Wagner et al. 1990].

Māmaki leaves are quite variable in size, shape, and color; here we show a few extremes (Extra large leaf photograph courtesy of Sean Erroll MacDonald [gokotta4] CC BY-NC 4.0). Ripe (white) and unripe māmaki fruits; note the tiny achenes covering the surface of the fruit like a raspberry. Mature cultivated māmaki at Ulupalakua, Maui. (Photographs of fruits, cultivated plant, and leaves in header courtesy of Forest & Kim Starr CC BY 3.0 us.)

Description

Pipturus albidus is a morphologically variable species, particularly when it comes to its leaves. This has caused several taxonomists to formally divide it into separate species, subspecies, varieties, and forme (see Synonyms above). However, currently (2025) and until someone conducts a focused genetic study on this species, most botanists consider P. albidus to be a single but highly variable species. (Kari Bogner [2017] conducted a more general genetic study of Hawaiian Urticaceae.)

Pipturus albidus is a shrub to small tree (up to about 20 feet [6 m]) tall with a lifespan likely greater than five years in the wild but often shorter when cultivated (for reasons described in Growth Requirements). Its branches have a grayish-brown to reddish-brown bark and soft white-to-yellow wood that is flexible when alive but brittle when dead and dry. Māmaki has a watery sap sometimes used in making kapa (see Uses below).

Pipturus albidus leaves have three consistent features: (1) they feel like sandpaper, (2) the upper surface is darker than the lower surface, and (3) they have serrated to scalloped margins. Otherwise, māmaki leaves can vary in every other way, either between populations or, to a lesser extent, between individual plants growing in the same population/location. Leaves can be anywhere from lance-like to heart-shaped, 2 to 12 inches (5 to 30 cm) long, light to dark green (sometimes being nearly white on their lower surface), and with or without impressed veins that can be only slightly visible to dramatically highlighted in pink or red. (Cultivated plants can also change the size and color of their leaves depending on the amount of sunlight and water they receive.)

Given the tiny size of their flowers and the fact that we have not seen or grown every type of Pipturus albidus in Hawai‘i, we can only state that all the māmaki we have grown were able to produce seeds, implying that they had both male and female flowers. Further, our mature plants almost always had developing flower clusters and ripening fruits year-round. According to Wagner et al. [1990], P. albidus develops clusters of unisexual male and female flowers along the plant's branches with the female flowers becoming progressively more common toward the branch's apex (i.e., tip). Wagner et al. [1990] also state that there are plants that have only male or only female flower clusters.

A Pipturus abidus fruit (more properly referred to as an aggregation of "receptacles") resembles a small raspberry, turning from green to white as it ripens, with many very tiny achenes (the true single-seeded fruits) embedded on its outer surface. The ripe fruits are edible but bland to subtly sweet.

Growth Requirements

General

Pipturus albidus does best in a lightly shaded site such as beneath a medium to large tree that permits some sunlight through its leaves. However, most forms will also survive in full sunlight; smaller leaf and red-veined forms seem to adapt best. Plant māmaki three to six feet (1 to 2 m) apart to create an informal (i.e., minimally pruned) hedge or screen. Māmaki can also be kept in a container but will become stunted if not sequentially transferred to a larger and larger pot.

Māmaki is generally not suited to hot and dry or coastal sites, since it is intolerant of drought and salt spray. If planted in either of these environments, try to compensate by frequent watering, shading, and protection from winds, particularly those coming from the ocean. At any site, māmaki needs moist to wet soil surrounding its roots. The soil can be lava/cinder, clay, or organic dominant; we have never tried to grow māmaki in sand or coralline soils. However, this soil must also drain water well to discourage root rot caused by fungi or bacteria.

Under optimum conditions, māmaki grows fast and matures quickly; it's not unusual to have a shrub six (2 m) feet tall producing lots and lots of fruits in less than a year. However, it has also been our experience that māmaki (in the landscape) don't live very long — about three to five years — before showing signs of senescence (e.g., dying branches, reduced growth) and dying. Sometimes this death is slow with a gradual loss of branches and leaves, and sometimes it is quick (i.e., in days or weeks). While it seems unlikely that māmaki are this short-lived in the wild, we suspect that their shorter life when cultivated is because of some pathogenic soil microbe that eventually overwhelms the plant's defenses. Alternatively, perhaps, cultivated conditions are just so optimal that the plant "burns itself out." Hopefully, as more and more people grow māmaki, we will have a better understanding of its lifecycle and how to prolong it. (Local māmaki farmers report they can get multiple leaf harvests for two to five years before the plants need to be replaced [Koher et al. 2023].)

Māmaki seems to benefit (e.g., better color and growth) from an application of a balanced controlled-release fertilizer with minor elements every six months or a monthly foliar feeding with an organic or inorganic water-soluble fertilizer diluted to ⅓ to ½ its recommended strength. Even without fertilizer, māmaki will often become top-heavy, causing it to tip over and uproot. Prevent this from happening by: avoiding a windy planting site, selective pruning to increase airflow through the plant, and supporting the plant with stakes and ties.

Regularly removing the growing tips of māmaki will encourage branching and new growth. Top branches can also be removed to keep leaves within reach for harvesting. However, avoid over-pruning or over-harvesting by not removing more than a quarter of your māmaki's leaves at one time. Afterward, do not prune or harvest for several weeks to give the plant time to recover.

Pests and Diseases

Māmaki can become infested by sap-sucking insects such as aphids, mealybugs, scale insects, spittlebugs, and thrips. These, in turn, can be farmed and protected by ants. Over-fertilized plants seem to be more prone to these infestations. Also, Chinese rose beetles, caterpillars, and grasshoppers will chew holes in māmaki leaves, making them unsightly but usually not adversely affecting the overall health of the plant, provided the damage is not severe. Young plants are sometimes quickly killed by an unidentified (fungal?) disease that causes the leaves and stems to quickly wilt and die. Refer to the Pests & Diseases page for treatments to control the above-mentioned pests — HOWEVER, if you intend to harvest māmaki leaves or fruits for consumption, use only the mildest of chemical treatments, such as insecticidal soaps and organic oils.

Uses

Ancient Hawaiian

The inner bark fibers of māmaki were used to make a brown kapa that was highly valued, perhaps because it was more difficult to make than kapa made from wauke (Broussonetia papyrifera; paper mulberry); the fibers were also occasionally used to make cordage [Abbott 1992]. Māmaki kapa was durable, but only when dry, and tore like paper if it got wet or was washed, whereas kapa made from wauke could be washed [Neal 1965] [Krauss 1993]. It was most commonly made on Hawai‘i Island. On the other islands, māmaki was usually mixed with wauke when making kapa [Krauss 197-]. When finished, māmaki kapa was scented with ʻōlapa (Cheirodendron spp.) bark or the roots of kūpaoa (Dubautia spp.) [Abbott 1992].

Māmaki sap mixed with water was used as a wetting solution during the kapa-making process [Krauss 1993].

As a preventative medicine for ‘ea (childhood thrush), women would first eat māmaki fruits during the later months of pregnancy. Then, after giving birth, the mother would chew a few māmaki fruits before feeding them to her infant. Once old enough to chew, the child would eat several fruits until she or he was a year old. Fruits were also eaten as a mild laxative and used as a dressing for sores and wounds. Māmaki leaves were used to make a hot tea for "general debility," an old-fashioned term for a feeling of weakness [Krauss 197-] [Krauss 2001].

Modern

Today, fresh or dried māmaki (Pipturus albidus) leaves are used to make a tea, supporting a small commercial market that sells the dry leaves of locally farmed plants. The tea has been described as "having an earthy and nutty flavor, with a natural sweetness and a lack of bitterness." Māmaki leaves have been shown to have antioxidant, anti-inflammatory, anti-microbial, and anti-viral properties that are possibly useful for the treatment of various ailments. However, the numerous health benefit claims (e.g., cholesterol and blood pressure reduction, blood sugar regulation, stress relief, liver health) currently lack significant scientific verification and characterization.

The above paragraph is an extremely brief summary of an excellent recent and comprehensive review of māmaki (Pipturus albidus) by Koher et al. [2023] available online. If you are interested in the details of the review, we highly recommend you read the complete article.

Special Features and Information

General

The Nettle family (Urticaceae) includes about 2,625 species within 53 genera worldwide, with many species having stinging hairs [WikipediA;Urticaceae]. Other native Urticaceae include: the endemic ʻākōlea (Boehmeria grandis); five endemic Neraudia species; the indigenous Pilea peploides; three additional endemic species of māmaki (Pipturus spp.); the endemic olonā (Touchardia latifolia) and hona (Touchardia oahuensis); the endemic ōpuhe (Urera kaalae); and the endemic Urtica sandwicensis, a rare but sometimes locally common annual herb and the only Hawaiian nettle with stinging hairs. It is restricted to the alpine and subalpine plateau between Hualālai, Mauna Loa, and Mauna Kea on Hawaiʻi Island [Flora of the Hawaiian Islands].

Māmaki is one of the best native plants to attract Hawai‘i's only two native butterflies, the pulelehua or Kamehameha butterfly (Vanessa tameamea), the official State insect, and the Koa or Blackburn butterfly (Udara blackburni) — a good reason to avoid using insecticides on māmaki.

ʻĀkōlea (Boehmeria grandis) is often misidentified as māmaki because of its similar appearance. However, the two should not be confused with each other, particularly because of their differing medicinal uses [Leonard 2012].

Hawaiian Name

According to Krauss [197-], māmake or mamake with an "e" instead of an "i" at the end is a misspelling. Waimea is the name for this species on Kauaʻi, a name also used on Maui for the endemic olomea (Perrottetia sandwicensis); both species often have red-veined leaves [Pukui & Elbert 1986].

Etymology

Pipturus is derived from the Greek words, pipto, meaning "to fall" and oura, meaning "tail," referring to the stigma (the part of the female flower receptive to pollen) falling off early [Wagner et al. 1990]. The species name, albidis, is Latin for "white" [Geldhill 2008], perhaps a reference to the color of the underside of the plant's leaves or its ripe fruits.

BPK