Stickybud pritchardia
Pritchardia Viscosa • Loulu • Lo'ulu
The Essence
"Pritchardia viscosa is a Critically Endangered fan palm restricted to the windward side of Kaua'i, Hawai'i. Joseph Rock described it in 1921 from a collection he had made in Kalihiwai Valley the previous year, and it was not seen again for some seventy years — until 1990, when naturalist John Obata and National Tropical Botanical Garden botanist Ken Wood observed it in the same general area as Rock's type locality, off the Powerline Road. That rediscovered group held one juvenile and two mature plants; Hurricane 'Iniki destroyed three further plants of the population in 1992, which USFWS records as half of the known individuals. The 2020 IUCN assessment puts it in a single location with three mature individuals, all in one subpopulation, and notes that the fewer than 50 individuals that remain are wholly confined to that one subpopulation; the Palm Specialist Group likewise states that only three individuals remain in the wild. The species is unmistakable within its genus: the Palm Specialist Group calls it the only member of Pritchardia whose flowers and buds — calyx and corolla — are covered in a thick viscous coating as if varnished, with rachillae that are glabrous and viscous, while Hodel (2007) writes that the viscous panicles and flowers alone are diagnostic. IUCN lists the current threats as seed predation by rats, pigs and humans together with competition from invasive introduced plants including Psidium cattleianum (strawberry guava), Paspalum conjugatum (Hilo grass) and Clidemia hirta; the Palm Specialist Group adds that introduced deer, goats and pigs reduce seedlings by grazing and uprooting them. USFWS records that at least one of the three remaining trees was damaged by spiked boots used by a botanist or seed collector to scale it and collect seed or reference material, and the Palm Specialist Group describes that stem damage as permanent. IUCN calls it a charismatic palm subject to illegal collection of seeds and records that one juvenile individual was dug up illegally, causing a decline in the population. Hawai'i's Department of Land and Natural Resources, Division of Forestry and Wildlife maintains a fenced exclosure around two individuals and metal rat guards around their stems, and ex situ collections of known wild origin are held at botanic gardens on Kaua'i and O'ahu."
The genus commemorates William Thomas Pritchard (1829–1907), a British official and consul stationed in Fiji in the 19th century and author of Polynesian Reminiscences (1866). The epithet viscosa is Latin for viscous or sticky; USFWS states that it 'refers to the very viscous inflorescence, calyx, and corolla'. Loulu is the general Hawaiian vernacular name for Pritchardia palms.
Described by Joseph Rock in 1921 in Beccari and Rock's monographic study of the genus Pritchardia (Memoirs of the Bernice P. Bishop Museum 8: 1–77, the name itself on p. 66), based on his own 1920 collection from Kalihiwai Valley — the only known gathering for the next seventy years. The species was listed as Endangered under the US Endangered Species Act in the USFWS final rule of 10 October 1996 covering nineteen plant species from the island of Kaua'i, effective 12 November 1996. That rule expressly declined to designate critical habitat for the nineteen taxa, but listing automatically invoked listing under Hawai'i state law, which prohibits taking of listed plants; the 2020 IUCN assessment states that the species now has a recovery plan and designated critical habitat and cannot be collected, sold, shipped or grown without a state permit. The Palm Specialist Group notes that Pritchardia is the only member of the palm family native to Hawai'i, with 23 known single-island endemic species, giving Hawai'i the richest palm diversity in terms of species in the United States.
Natural Habitat
IUCN describes it as an endemic palm tree of open Metrosideros–Dicranopteris ('ohi'a–uluhe) lowland wet forest at 535 m elevation on the north side of Kaua'i, occurring with native associates including Pritchardia waialealeana, Psychotria, Melicope, Antidesma platyphyllum, Scaevola procera, Coprosma, Pittosporum, Syzygium sandwicense, Ilex anomala, Cibotium and Clermontia. Published elevation figures differ considerably by source: 427 m (IUCN/SSC Palm Specialist Group), 510 m (USFWS, at the rediscovery site on State land), 535 m (IUCN), and 600–800 m per Hodel (2007), whose Palmpedia text also gives 1,600–2,300 ft on the same page. USFWS characterises the site as 'ohi'a–uluhe lowland wet forest with associates including 'aiea, 'ahakea, hame, hapu'u and kopiko, while the Palm Specialist Group describes it as degraded open mesic forest on a clay-soil substrate where the palm grows as a congener with P. waialealeana, P. hardyi and P. flynnii. POWO classes its climate as wet tropical.
Specimen Gallery Under Curation
Discovering authentic visual assets in the field...
Biology & Morphology
"A solitary fan palm — reported as 3–8 m by USFWS, 6–8 m by Wikipedia and 6–13 m by the Palm Specialist Group — with a grey-brown, vertically striated stem 16–21 cm in diameter at breast height carrying an open crown of about 10–20 costapalmate leaves whose flat blades are divided about one third and appear silvery greyish-white beneath from a complete covering of lepidia. The inflorescences are shorter than the petioles and carry extremely sticky, shiny flowers in two opposite rows; USFWS and the Palm Specialist Group both give one to three panicles, while Hodel (2007) gives one to five. The fruits are borne in dense clusters, ellipsoid to obovoid and 19–40 x 12–21 mm per Hodel (up to about 40 x 25 mm per USFWS and the Palm Specialist Group), green when unripe and ripening black."
Morphology
Symmetrical columnar trunk with characteristic leaf-scar patterning and lignified outer cortex.
Adventitious root system spreading radially to maximize hydraulic intake in competitive soil matrices.
Distinctive unknown habit and medium stature providing a unique architectural profile.
Foliage
Vibrant green canopy featuring characteristic frond architecture optimized for photon interception and transpiration efficiency.
Specialized green tissues exhibiting moderate metabolic expansion rates.
Reproduction
Complex inflorescence branching typical of the Pritchardia clade, exhibiting seasonal reproductive synchrony.
Nutrient-dense drupes encased in a fibrous pericarp, optimized for protection and dispersal.
Dormant embryonic tissues with high endosperm density, characteristic of resilient Pritchardia specimens.
Ecology
Active rhizosphere communication with mycorrhizal fungal networks, enhancing phosphorus and micronutrient uptake.
Interlocked with local entomological vectors, primarily Meliponini bees or specialized coleoptera.
Gravity-mediated and animal-vectored dispersal mechanisms ensuring regional genetic distribution.
Germination & Propagation
Germination Timeline
Hydration soak.
Incubation in moist media.
Sprout emergence.
No germination protocol specific to Pritchardia viscosa was found in the sources consulted. The Bishop Museum Ethnobotany Database rates loulu propagation as easy, with plants of about a foot ready for the ground or a larger pot, and advises hand-pollination because seeds become hybridised if many species are grown in the same vicinity. The 2020 IUCN assessment lists among needed research that collection of material for genetic storage 'will need to be either by cryopreservation or possibly -80 deg. C', implying conventional seed banking is not straightforward for this species.
Cultivation & Care
Light
Palmpedia (quoting llifle) reports it prefers full sun but tolerates half-day sun, with full-sun plants growing more compact, and summarises that it prefers a sunny, well-drained and moist position.
Water
Needs regular water and should not be allowed to dry out between waterings, but must not sit in continually wet, mucky soil, as the roots and lower trunk can rot (Palmpedia, quoting llifle). Its wild habitat is lowland wet forest and POWO classes its climate as wet tropical.
Soil
Prefers organic soil but adapts to clay and loam, slightly alkaline or acidic, with good drainage important; plants raised in dry or infertile soils tend to be smaller in stature with smaller leaves (Palmpedia, quoting llifle). The Palm Specialist Group records the surviving wild plants as growing on a clay-soil substrate. Palmpedia also carries advice from Dr David Eickhoff that loulu need a complete palm fertiliser with minor elements, magnesium and potassium deficiencies being two of the most serious nutritional disorders in palms, especially for loulu in pots.
No USDA hardiness zone is given in any authoritative source retrieved. Palmpedia (quoting llifle) says only that it is adapted to tropical and subtropical climates and that young plants are more cold sensitive; POWO records the climate as wet tropical. Palmpedia photo records document cultivated plants in Hawaii and in San Diego and Spring Valley, California, and Geoff Stein, quoted there, calls it extremely rare in cultivation as well as in the wild.
Pests, Diseases & Care
Pests
Brassolis sophorae (Coconut Caterpillar)
MODERATEDefoliation of pinnate leaflets, reducing photosynthetic capacity.
Manual removal and application of Bacillus thuringiensis (Bt).
Chrysomphalus aonidum (Florida Red Scale)
MODERATEYellow spotting and premature leaf drop in high-humidity zones.
Introduction of Aphytis holoxanthus (parasitic wasp).
Diseases
Phytophthora palmivora (Bud Rot)
CRITICALNecrosis of the spear leaf and decay of the meristem.
Fosetyl-Al application and optimizing canopy ventilation.
Ganoderma zonatum (Butt Rot)
LETHALRadial wood decay and structural instability at the base.
No chemical cure; immediate isolation and removal.
Nutritional Deficiencies
Interveinal chlorosis (Younger fronds)
Chelated Fe-EDDHA Soil Pulse
Marginal chlorosis (Older fronds)
Mg-Sulfate (Kieserite) saturation
Frizzletop / Distorted spear
Systemic Mn-Sulfate application
Care Tips
Biosurveillance pulse synchronized for Global regional vectors.
Apply prophylactic fungicidal drench in the nocturnal phase.
Improve canopy ventilation to disrupt fungal sporulation cycles.
Sources & Conservation
Curated- Plants of the World Online (POWO) — Pritchardia viscosa Rock · accessed 2026-08
- IUCN Red List — Pritchardia viscosa (Clark, Nyberg & Wood 2020, e.T38655A83788107) · accessed 2026-08
- USFWS / Federal Register vol. 61 no. 198 (10 Oct 1996): Determination of Endangered or Threatened Status for Nineteen Plant Species From the Island of Kauai, Hawaii · accessed 2026-08
- IUCN/SSC Palm Specialist Group Virtual Herbarium — Pritchardia viscosa (M.H. Chapin & M. Maunder) · accessed 2026-08
- Palmpedia — Pritchardia viscosa (incl. Hodel 2007 / Palmweb description) · accessed 2026-08
- Wikipedia — Pritchardia viscosa · accessed 2026-08
- GBIF Backbone Taxonomy — Pritchardia viscosa Rock (key 5294665) · accessed 2026-08
- Bishop Museum Ethnobotany Database — loulu (Pritchardia) · accessed 2026-08
- PACSOA Wiki — Pritchardia Overview · accessed 2026-08