Myoporum stellatum with less fuzzy leaves. (Compare this plant to the fuzzier naio in the header photograph; Myoporum stellatum is highly variable in several morphological characteristics.) Myoporum stellatum flower (note stellate hairs on stems and leaves). Magnified leaf showing stellate hairs. Wild naio in protected enclosure, O‘ahu. (Flower, magnified leaf, and wild naio photographs courtesy of Hubert Szczygieł CC BY-NC 4.0) Naio outplanted on Midway Atoll (Photograph courtesy of Forest & Kim Starr CC BY 2.0). Lantana lace bug (Teleonemia scrupulosa) with leaf damage (i.e., yellowing and distortions). Naio thrips (Klambothrips myopori) damage to Myoporum sandwicense, the other naio (Photograph from OISC webpage). The lantana lace bug is easily visible to the naked eye, while naio thrips are difficult to see.

Growth Requirements

General

    In the early 2000s, Myoporum sandwicense, the other more common naio, was becoming an increasingly popular landscape plant in Hawai‘i. In particular, a glossy-leaf prostrate form from Hawai‘i Island had entered the commercial market and was becoming a favorite of hotels, shopping centers, and residents. That all changed in 2009 when the alien Myoporum thrips (Klambothrips myopori), native to Tasmania, was accidentally introduced to Hawai‘i Island from California where it had already decimated the ornamental Myoporum (M. laetum and M. pacificum) there. The State quickly began eradication efforts, removing infested and sometimes uninfested naio, in an attempt to curb the spread of this lethal pest. Unfortunately, despite these efforts, the tiny insect island-hopped to O‘ahu in 2018, continuing to disfigure or kill both cultivated and wild naio (both M. sandwicense and M. stellatum). Following the spread to O‘ahu, State efforts shifted from eradicating infested plants on the two Islands to trying to prevent the thrips from spreading further to the remaining Hawaiian Islands using monitoring and interisland inspections and restrictions. 

    Currently (2025), the State continues to encourage the public not to plant naio. However, we have an alternative recommendation for those of you willing to put in the extra time and effort. Past is the time of planting and trying to maintain a multi-plant naio groundcover or hedge, particularly one using a form like the once-popular prostrate naio (which was especially hard-hit by the Myoporum thrips). Rather, we encourage you (again, only if you can put in the effort and are willing to remove and destroy your naio if it is beyond saving) to grow one or two of the lesser-known forms of naio in an effort to discover thrips-resistant varieties of Myoporum stellatum (or M. sandwicense) and help secure naio's future in Hawai‘i. Following are our recommendations with this goal in mind.

    Try to obtain a Myoporum stellatum form that shows some anecdotal evidence of Myororum thrips resistance. Based on our observations and the research of others [Kaufman et al. 2021], Myoporum stellatum seems to be less susceptible to attack and dieback by naio thrips than M. sandwicense. This is not to say all M. stellatum are immune to this pest; they're not, just that the damage is less severe. Naio can be propagated from cuttings, so this makes it easier to obtain new M. stellatum forms from other like-minded native Hawaiian plant enthusiasts. 

    Be prepared and comfortable to use insecticides; if you're not, you probably should not attempt this naio project. So far, safe sprays like insecticidal soap and horticultural oil, as well as contact insecticides like malathion, have been only marginally effective at controlling Myoporum thrips because the insects live between and are protected by the distorted leaves they create. Therefore, pruning and destroying infested branches along with using systemic insecticides has been more effective. See additional control information below in Pests and Diseases. To date (2025), there are no known biocontrols for Myoporum thrips; however, scientists in both Hawai‘i and California are working hard to find them. 

    You should grow only one or two naio (at one time) so you can easily accommodate the monitoring and care they will require. Also, keeping them in a container will allow you greater control than planting them in the ground. However, keep the container outside so your naio is potentially exposed to Myoporum thrips; we can't discover resistant varieties if we all keep our naio inside.

    Place your naio in a site that receives full sunlight for all or most of the day. Myoporum stellatum grows naturally in very dry places. Therefore, whether it is in a container or in the ground, you should water it very little once its roots are established (e.g., once or twice a week in a container; once a month or not at all if it's in the ground); the surface media or soil should be dry most of the time. M. stellatum requires easily draining media, so fill your container with 25% to 50% black cinders or perlite. Likewise, an in-the-ground plant needs soil that easily drains away water.   

    Naio generally grows quickly in the ground and begins flowering within a year or two. In a container, expect them to grow more slowly and eventually become (non-fatally) stunted if not occasionally transferred to a larger container. Container naio benefit from biannual applications of a balanced controlled-release fertilizer with minor elements or monthly foliar feeding with an organic or inorganic water-soluble fertilizer diluted to ⅓ to ½ the recommended strength. Naio in the ground do not require fertilizer. 

    Monitor your naio regularly for Myoporum thrips and act immediately if you see any evidence of their presence. Remove and destroy any infested branches and treat the plant with a systemic insecticide if you haven't already. Spraying with horticultural or neem oil can also help — a little — by deterring the thrips from hopping to other branches. Record your efforts and keep informed. Hopefully, a biocontrol agent will be found, and you'll want to know asap. Lastly, share your experiences (and cuttings from your naio forms) with others. 

Pests and Diseases

    Before Myoporum thrips, diseases and pests were minor problems for anyone with naio in their landscape. Overwatered plants would sometimes get a black sooty mold growing on their leaves. And aphids, mealybugs, scale insects, or spider mites would occasionally infest a plant's stem-tips, or a black twig borer would kill a branch. However, we never saw these attacks kill a naio, and, often, the disease or pest would disappear without treatment. Refer to the Pests & Diseases page for ways to deal with each of these pests if they do not go away on their own. 

    Curiously, the most common pest of Myoporum stellatum (but, not M. sandwicense) before 2018 was the introduced lantana lace bug, Teleonemia scrupulosa. Introduced to Hawai‘i by a relative, Albert Koebele, over a hundred years ago as a bio-control agent for the invasive lantana that was taking over cattle rangeland, the lantana lace bug jumped hosts (who knows when) and now attacks M. stellatum. Fortunately, these attacks are, in our experience, never fatal and easily managed. Infestations are most common during the dry hot summer and often disappear on their own with cooler wetter winter weather. If you don’t want to wait, several sprayings of horticultural oil about a week apart will kill this pest.

    Today (2025), the future of naio in Hawai‘i is seriously threatened by the Myoporum or naio thrips (Klambothrips myopori), an introduced insect barely visible to the naked eye. Accidentally introduced around 2009, probably hitching a ride on landscape plants imported from California, Myoporum thrips have decimated most of the wild and nearly all the cultivated naio (Myoporum sandwicense) on Hawai‘i Island. In 2018, this terrible pest island-hopped to O‘ahu and has attacked both naio species. In 2024, naio thrips were detected on Moloka‘i, and, in 2025, they were found on Kaua‘i [Hawaii Invasive Species Council].

    Currently (2025), there is no effective method of halting this plague. While the thrips themselves are difficult to see, the damage they cause is quite recognizable (see the photograph above). For more information on Myoporum thrips, visit the Hawaii Invasive Species Council Naio Thrips page or the Oʻahu Invasive Species Committee (OISC) webpage. Immediate pruning and destruction of infested branches and systemic insecticides are currently the best treatments we have against this deadly pest. Unfortunately, there are few systemic insecticides available in Hawai‘i and even fewer sold in most local garden shops (i.e., those containing imidacloprid or spinosad). Check out this University of California IPM site for more information on chemical controls for Myoporum thrips.

Special Features and Information

General

    The Figwort family or Scrophulariaceae has around 60 genera and 1,830 species worldwide [WikipediA;Scrophulariaceae]. 

    There are three recognized endemic species of Myoporum in Hawai‘i: the common Myoporum sandwicense (formerly found on all main Hawaiian Islands but now extinct on Kaho‘olawe), and two rare species: M. degeneri (endemic to dry forests from ʻUlupalakua to Kaupo Gap, East Maui), and M. stellatum (ʻEwa Plains and Nānākuli Valley, Oʻahu). The populations of Myoporum outside the Hawaiian Islands, naturally found on Mangaia (Auʻau Enua) in the Cook Islands, were formerly classified as Myoporum sandwicense. These plants are now classified as a distinct species, Myoporum wilderi, locally called ngaio and restricted to Mangaia, but also cultivated on Rarotonga by the Indigenous people who use the flowers to scent coconut oil [Chinnock 2007].

Hawaiian Name

    All native Myoporum species in Hawai‘i are referred to as naio. This is also the name for a parasitic pinworm (Enterobius sp.), a type of seaweed, and an inferior kalo left in the field after harvest [Pukui & Elbert 1986].

Etymology

    Myoporum is derived from the Greek myo, meaning "close," and poros, meaning "pore," in reference to the close appearance of the leaf glands of these plants [Wagner et al. 1990]. The species name, stellatum, is Latin, meaning "star-like," a reference to tiny star-shaped hairs on the leaves [Gledhill 2008].