Pictured here is a cultivated ʻānaunau (Lepidium owaihiense) habit, flowers, green seed pods, and dried ripe seed pods with seeds. The seedlings will come up most anywhere, such as cracks in concrete or rock walls, among weeds, in lawns, and in nearby potted plants. The habit of a mature cultivated ʻānaunau with flowers and fruit, along with numerous keiki growing with other natives such as pua kala [Argemone glauca] and Oʻahu vigna [Vigna owahuensis]. ʻĀnaunau outplanted on Midway (Pihemanu), growing on sandy soil with kāwelu [Eragrostis variabilis], where it was once extinct (Photograph courtesy of Forest & Kim Starr CC BY 3.0 US.).

Growth Requirements

General

    ʻĀnaunau is not difficult to grow at all and does not seem to be picky with the type of media used. Naturally, it is found on the dry side, but it does appreciate moisture, and the foliage will be more lush, but the soil must be well-drained. I [Eickhoff] prefer to water my plants when the leaves start to droop slightly. You will get to know your plants and its needs. It does well in potting containers in partial to full sun or in the ground with full sun.

    It does well in sand, cinder or coral potting media and will often appear in soils (e.g., salty) that most other natives would not be able to grow in. ʻĀnaunau are salt spray, drought, wind and heat tolerant. The plants are relatively short-lived (under 5 years) but produce abundant seeds, which will self-propagate, and plants will come up most anywhere, such as cracks in concrete or rock walls, among weeds, in lawns, and in nearby potted plants.

    The spent flowers/fruits can be trimmed off for a cleaner appearance. But allowed to produce seeds can form a dense groundcover, sometimes even weedy. ʻĀnaunau seems more suited for the herb garden than as a landscape plant. The edible flowers and leaves have a peppery smell with a mild to sharp flavor and can be added to spice up green salads.

Pests and Diseases

    Lepidium owaihiense is prone to minor or major infestations of red spider mites. Thrips can be problematic at times if not immediately controlled. Refer to the Pests and Diseases page for ways to deal with each of these pests. 

Special Features and Information

General

    Lepidium owaihiense is a member of the Brassicaceae family, commonly known as the Mustard Family, which includes notable relatives such as mustard, cabbage, turnip, horseradish, and wasabi. Known locally as ʻĀnaunau or pepperweed, Lepidium owaihiense shares the characteristic sharp, peppery flavor of its global counterparts.

    Within the Hawaiian Islands, there are five endemic species. Among these, Lepidium serra, also referred to as ʻānaunau from Kauaʻi, appears to have a stable population. However, two other species, Lepidium arbuscula from the leeward Waiʻanae Mountains on Oʻahu and Lepidium orbiculare from Haʻupu Ridge, Kauaʻi, are classified as endangered. The fifth species, Remy's pepperweed (Lepidium remyi), was initially considered a variety of Lepidium bidentatum. It was first collected by French naturalist Jules Achille Rémy between 1851 and 1855 on Hawaiʻi Island, though the specific locality remains unknown. A subsequent collection by Otto Degner in 1949 in a "Metrosideros" forest on the 1859 lava flow is likely representative of this species. Unfortunately, Remy's pepperweed is now presumed extinct [Flora of the Hawaiian Islands].

    There is also at least seven naturalized (non-native) Lepidium spp. in the islands [Flora of the Hawaiian Islands].

    When reading older literature for this species, it will be good to keep in mind that it is now taxonomically referred to as Lepidium owaihiense and formerly as Lepidium bidentatum var. o-waihiense. Lepedium bidentatum var. bidentatum is native to the Pacific region but is not found in the Hawaiian Archipelago, and the varietal epithet o-waihiense was moved to a species status as owaihiense, less the dash. This will make sense when this species is cited in literature. It is common for plants to change genus and species, even going back to an older name as in this case with Lepidium owaihiense. The constant changes in taxonomy and other reasons were a major decision in why we have chosen to create a website where we can update information, and not a book that once it's in print, it's permanent. Plus, websites save trees too!

Hawaiian Name

    Naunau, same as ʻĀnaunau, is a reduplication of nau; to munch one's words and speak indistinctly, mumble [Hawaiian Dictionaries]. 

Etymology

    The generic name Lepidium is derived from the Greek lepis, scale, in reference to the small, flat, scale-like fruit [Wagner et al. 1990]. The former specific epithet bidentatum is from the Latin bidentatus, double-toothed, referring to the serrated or toothed leaves [Gledhill 2008]. The specific epithet o-wahaiense has reference to an old spelling version of O-Waihi for Hawaiʻi [Schütz 1995].

    Interestingly, regarding Owyhee County (Idaho), author William Bright notes: "From Chinook Jargon [owáihi] 'Sandwich Islands, Hawaiʻi, borrowed either from English or from the Hawaiʻian form Hawaiʻi, at a time in the early nineteenth century when a number of Hawaiʻians had settled in the Pacific Northwest (D. Kinkade p.c.) The placename Owyhee also occurs in Ore. (Malheur Co.)" [Bright 2007].