The “Nalea Plant” is a general term for an exceptionally rare Hawaiian species, Kanaloa kahoolawensis, also known as Ka Palupalu o Kanaloa. This plant, once believed extinct, represents a new genus discovered in modern times. Its rediscovery highlights the need for conservation of Hawaii’s unique plant life.
Nalea’s Unique Features
Ka Palupalu o Kanaloa (Kanaloa kahoolawensis) is a densely branched shrub, typically 0.75 to 1 meter (2.5 to 3.5 feet) tall. Its branches can spread 0.75 to 1.5 meters (2.5 to 4.9 feet) in length, and new growth is covered in fine, soft brown hairs.
The plant’s leaves are divided into six oval-shaped leaflets, each 2.7–4.2 cm (1.1–1.7 inches) long and 1.4–3.2 cm (0.6–1.3 inches) wide. It produces small, yellowish-white flowers in ball-shaped clusters, about 7.0–8.5 mm (0.28–0.33 inches) across, with 20 to 54 flowers per cluster, predominantly male. Following flowering, the plant forms flat, round, or oval fruit pods, 2.4–3.2 cm (0.9–1.3 inches) long and 2–2.3 cm (0.8–0.9 inches) wide, each usually containing a single heart-shaped, dark brown to black seed.
Natural Habitat and Range
Ka Palupalu o Kanaloa was first discovered in 1992 on a steep rocky spire off the coast of Kahoʻolawe, one of the smaller Hawaiian Islands. This remote location, the cliffs of ʻAleʻale Puʻuloae, sits at an elevation of 45–60 meters (148–197 feet) above sea level. The plant thrives in dry, rocky slope conditions within sparse native shrubland, an environment receiving less than 26 inches of precipitation annually.
Historical pollen studies suggest the plant once had a broader distribution across the Hawaiian Islands. Fossilized pollen, likely from this species, has been identified in core samples from Oʻahu, Maui, and Kauaʻi. This indicates it was once a more widespread component of Hawaii’s dryland flora, potentially co-dominant with species like Dodonaea viscosa and Pritchardia palms. The species disappeared from the pollen record around the 16th century.
Conservation Status and Threats
Ka Palupalu o Kanaloa is categorized as critically endangered and was declared extinct in the wild in 2015. Only two wild plants were known at the time of its 1992 rediscovery, and these eventually perished. Today, the total population consists of approximately 20 plants, all maintained in cultivation.
The plant faces numerous threats. Competition from invasive plant species, such as buffle grass, impacts its establishment. Non-native animals, including feral ungulates like pigs and goats, rats, slugs, cats, and mice, threaten through browsing and seed predation. Habitat degradation from historical overgrazing and erosion on Kahoʻolawe has also reduced suitable growing areas.
The island’s past use as a bombing range has left unexploded ordnance, which complicates restoration efforts. Climate change, particularly increased drought frequency and severity, negatively affects the plant’s arid habitat. The small number of remaining individuals also leads to reduced reproductive vigor, making the species susceptible to stochastic events like high winds, tsunamis, hurricanes, landslides, and fires.
Conservation and Recovery Efforts
Extensive efforts are underway to prevent the extinction of Ka Palupalu o Kanaloa and facilitate its recovery. Propagation plays a central role, with horticulturalists successfully growing new plants from both seeds and cuttings. Notably, breakthroughs in producing rooted cuttings and germinating seedlings have significantly increased the cultivated population.
Several organizations collaborate in these conservation initiatives. These include:
Hawaiʻi Department of Land and Natural Resources’ Division of Forestry and Wildlife (DOFAW)
Kahoʻolawe Island Reserve Commission (KIRC)
Plant Extinction Prevention Program (PEPP)
National Tropical Botanical Garden (NTBG)
University of Hawaiʻi’s Lyon Arboretum
Maui Nui Botanical Garden
These partners are part of the broader Laukahi: The Hawaiʻi Plant Conservation Network.
Conservation actions encompass comprehensive habitat restoration and invasive species removal programs. Genetic material, including live plant tissue and frozen pollen, is meticulously stored at facilities like the University of Hawaiʻi’s Lyon Arboretum and a USDA facility in Colorado, safeguarding the species’ genetic diversity. Research initiatives continue to improve understanding of the plant’s reproductive biology and optimal growing conditions. The ultimate goal is to reintroduce Ka Palupalu o Kanaloa back into suitable protected areas within its historical range, ensuring its long-term survival in the wild.