Polyscias lallanii
(formerly Polyscias racemosa & Munroidendron racemosum)
Araliaceae or Ginseng family
Synonyms: Munroidendron racemosum, Munroidendron racemosum var. forbesii, Munroidendron racemosum var. macdanielsii, Polyscias munroi, Polyscias racemosa, Tetraplasandra racemosa
Pōkalakala
False ‘ohe, Munroidendron
Natural Range & Environment
Polyscias lallanii is a very rare and endangered tree endemic to Kaua‘i. According to the last (2022) 5-Year Review by USFWS, there are approximately 84 to 110 wild plants in about a dozen subpopulations on Kaua‘i, with most of the species' critical habitat on the northern side of the Island. Since it was first listed as endangered in 1994 (as Munroidendron racemosum), the number of subpopulations has declined, but because of more intensive surveys of remote sites, the number of wild plants has remained about the same. Botanical gardens and government agencies have collected (from almost all the known subpopulations) and stored more than 35,000 seeds. In addition, these gardens and agencies have propagated hundreds of new plants, with many being planted out near existing wild plants or in protected living collections [USFWS;ECOS]. Lastly, Polyscias lallanii is one of the few endangered Hawaiian plants permitted for commercial propagation and sale, and, therefore, is often available to the public.
Polyscias lallanii is found on vertical basalt cliffs, moderately steep slopes or talus terraces, and occasionally on basalt boulders near drainages from 6 to 979 m (20 to 3,212 ft) in dry to mesic native and nonnative-mixed forests [USFWS;ECOS].
It's not uncommon to have pōkalakala flowers on the same inflorescence or on separate inflorescences (on the same tree) be at different stages of development (Photograph courtesy of Jeff Steele [steeljef] CC BY-NC 4.0.). The many fruits on this long inflorescence will soon ripen as their flesh (i.e., mesocarp) turns soft and dark purple and attracts the attention of hungry birds. Don't panic when your pōkalakala drops all or most of its leaves at the onset of summer. This is natural and seems to happen regardless of how much water it receives; likely, the tree measures daylength to determine the season. Above is the same young (but reproducing) pōkalakala in summer and winter (Photographs courtesy of Forest & Kim Starr CC BY 3.0.). Under optimum conditions, a cultivated pōkalakala can grow quickly and tower well above your head in less than a decade. The new leaves of pōkalakala are densely covered with a thick silver to gold fuzz. However, as they mature, all or most of this fuzz is shed from the leaf's upper surface but retained on the lower surface (Photograph courtesy of G.D. Carr ©.). (Header photograph courtesy of Beardor on r/BotanicalPorn; reddit ©.)
Description
Polyscias lallanii is a small to medium-sized (up to about 25 feet [8 m] tall) extremely rare endangered tree with a lifespan well beyond five years. It has smooth gray bark, soft wood, and thick, semi-flexible branches similar to the ubiquitous alien plumerias here in Hawai‘i.
The undersurface of pōkalakala's large pinnately compound leaves is covered with a dense silver to golden fuzz, while the upper surface is glabrous (hairless); the unfolded new leaves emerging from the tip of a branch resemble tiny clasped hands (see photographs above). During the summer months, pōkalakala often drops some to all of its leaves, probably an adaptation to reduce water loss.
Polyscias lallanii produces hundreds of small perfect (bisexual) pale yellow flowers with red centers along a hanging rope-like inflorescence, sometimes as much as two feet (61 cm) long. In cultivation, pōkalakala has a long flowering and fruiting period, anywhere from July to February (in our experience), with the fall months being the most common time to see ripe fruits; before flowering, the tree will sometimes drop most or all of its leaves. When pollinated, the flowers develop into soft downy grape-size drupes with a dark purple pulp (when ripe), each containing several flat seeds.
Growth Requirements
General
We still don't understand why this stunningly beautiful tree isn't in nearly every residential frontyard in Hawai‘i. While it is extremely rare in the wild (i.e., critically endangered), it's often available for sale at local garden shops and plant sales. Pōkalakala is quite easy to grow and maintain in a lowland landscape where it will attract alien birds such as Mejiro and Japanese white-eye that will sip the nectar from its flowers as well as bulbuls and spotted doves that will eat its ripe fruits.
Use Polyscias lallani in a landscape as an accent, or, planted several feet apart, as an informal screen, or to create an area with moderate shade (during the winter months). Pōkalakala can also be grown in a container, provided you are willing to periodically transfer it to larger and larger pots as it grows; kept in the same pot, the tree will eventually become rootbound and stunted and will require additional care to maintain.
Polyscias lallani does fine in a site with full sunlight for the entire day. However, our pōkalakala have grown faster, branched more, and flowered sooner (after about three years) when positioned in a partially or lightly-shaded location.
Pōkalakala naturally grows in mesic areas on Kaua‘i and, therefore, cannot survive severe droughts the same way its sister species, ‘ohe makai (Polyscias sandwicensis), which grows in dry forests and shrublands, can. Knowing when and how much to water your tree needs can be tricky because pōkalakala often drops most of its leaves annually just before the start of its blooming season; this can trick you into thinking it is water-stressed. Ultimately, how much you need to water your pōkalakala will depend on the amount and seasonality of rain in your area. Our best advice is to monitor the soil moisture surrounding your pōkalakala and never let it become bone dry.
Polyscias lallanii can tolerate slight drought, strong winds, and salt spray. We have grown it in clay and organic-rich soils, and in containers with an easy-draining media mix (e.g., cinder, perlite). Pōkalakala kept in a container should be provided with a balanced controlled-release fertilizer with minor elements every six months, or sprayed every month or so with a foliar organic or inorganic fertilizer at ⅓ to ½ the recommended strength. Avoid pruning your pōkalakala except to remove a dead or diseased branch or an old and dried-up inflorescence (although these typically fall off on their own).
Pests and Diseases
Young pōkalakala are frequently attacked by sap-sucking arthropods such as aphids, mealybugs, white flies, and spider mites that usually focus their attention on the youngest leaves. Older plants seem to better ward off these infestations. Often, a few sprayings of horticultural oil will eliminate these pests if they don't disappear naturally. Similar to ‘ohe makai (Polyscias sandwicensis), the trunk at the soil-air interface seems to be the most vulnerable spot for both young and mature pōkalakala. Inspect this area frequently for damage caused by microbial rot or chewing pests (e.g., cockroaches, mice, rats), and intervene before it is too late. Also, take care when weeding not to wound this area. While we have not encountered these pests, Kerin E. Lilleeng-Rosenberger [2005] has seen ants and spotted leafhoppers on pōkalakala. David also once had some type of borer kill one of his mature trees very quickly. This pest produced a "sawdust" below the small holes it created in the trunk; therefore, we think it might have been a false powderpost beetle, which has attacked our stressed lonomea (Sapindus oahuensis) and uhiuhi (Mezoneuron kavaiense) in the past. Because this borer works fast, you need to respond quickly with a systemic pesticide like imidacloprid.
Uses
Ancient Hawaiian
We were unable to find any documented uses of pōkalakala by pre-contact (1778) Hawaiians; however, see Modern uses below.
Modern
Kapa-maker and Artist Kaʻiulani de Silva has found that the ripe fruits of pōkalakala yield a dark purple dye when wet, turning to a light plum color when dry [per. comm.].
Special Features and Information
General
The Ginseng family (Araliaceae) contains about 2,000 species within 46 genera with a pantropical distribution, although some species are found in temperate zones [Araliaceae Central]. In Hawai‘i, the notoriously invasive octopus tree (Heptapleurum actinophyllum formerly Schefflera actinophylla) is a member of the Ginseng family, and, unfortunately, still a popular ornamental that has taken over large areas of once native mesic and wet forest.
In addition to Polyscias lallanii, other native Hawaiian plants in Araliaceae include: five endemic species of ʻōlapa (Cheirodendron spp.); and ten additional endemic species of Polyscias with multiple Hawaiian compound names, most starting with ʻohe [Flora of the Hawaiian Islands].
Formerly, pōkalakala was placed in the endemic monotypic genus Munroidendron; a monotypic genus is a genus with a single species. Examples of monotypic genera endemic to Hawai‘i include: kanaloa (Kanaloa kahoolawensis), a very rare legume endemic in historic times to Kaho‘olawe; olonā (Touchardia latifolia), used by Hawaiians to make one of the strongest natural cordages in the world; and a tall native grass (Dissochondrus biflorus).
Hawaiian Name
Regarding the name pōkalakala, many have said that there is no known Hawaiian name for this species. However, The Story of Lānaʻi (page 199) notes that "an araliaceous plant, first [scientifically] discovered by Munro near Makaweli, Kauai in the early 1890s, and known to the Hawaiians as pokalakala, proved to be an undescribed genus which Dr. E.E. Sherff named Munroidendron" [Munro 2007] [brackets Eickhoff]. The addition of using a kahakō for the "ō" in pōkalakala was clarified to me [Eickhoff] on a botanical trip to Lānaʻi in 2005 with Bob and Doreen Hobdy and Leland Miyano while putting together the aforementioned publication. I asked Doreen how pōkalakala should be pronounced, since we were talking about plants named after George Munro and I had never heard of a Hawaiian name for this species. She believes it is with a "long ō" as with a kahakō. Unfortunately, for reasons unknown to me, the publication did not add the kahakō and I never inquired. However, the spelling with a kahakō is generally used and accepted today. A second and rarely-used name, pōkūlakalaka, has not yet been verified by references to be an early Hawaiian name.
Polyscias lallanii shares the name pōkalakala with the endemic Hawaiian prickly poppy (Argemone glauca), more commonly known by the name pua kala.
Etymology
Polyscias is from the Greek word polu-skiaj, meaning "many-shades," in reference to the plant's foliage [Gledhill 2008]. The former genus name, Munroidendron, was to honor George C. Munro (1866-1963), a pioneer in Hawaiian ornithology, botany, horticulture, and conservation [Wagner et al. 1990]. The Greek word dendron, meaning "tree," was added to the end of the name.
The species name, lallanii, is named after the late Shri Lallan Singh, father of the lead author (Singl), "who first instilled within the author a love for nature" [Singh & Kumar 2024]. The former species name, racemosa, is the feminine form of the Latin word racemosus, which means "cluster" or "bunch," [Wiktionary] referring to the spectacular hanging inflorescence of this species.
BPK