Loulu: The Hawaiian Palm

Appendix 3. Naturalized Palms in Hawai‘i

163 APPENDIX 3 Naturalized Palms in Hawai‘i At least six and perhaps more species of introduced or nonnative palms have escaped cultivation and are sometimes found in natural or seminatural areas of Hawai‘i. They serve as a reminder of Hawai‘i’s fragile ecosystems and vulnerability to invasion by nonnative species. Nonnative birds most likely assisted with the seed dispersal of these introduced palms. All, except the coconut, have small, colorful fruits, which attract birds. All are very adaptable species that require little care and naturalize fairly easily. Other nonnative palm species will likely naturalize in the future. On the Big Island, the Alexandra palm (often incorrectly called Alexander) (Archontophoenix alexandrae) populates valleys along streambeds and wet hillsides along the Hāmākua Coast where it forms vast, solid, pure if not handsome stands nearly to the exclusion of all other trees and shrubs (figs. 242 and 243). It is also naturalized on Kaua‘i in several moist valleys, such as Wainiha, and on O‘ahu along the Mānoa Falls Trail in FIGURE 242.\€ #" Y  "2‘i. Appendix 3 164 FIGURE 243.\€ #" Y   Hawai‘i. FIGURE 244. Chinese fan palm. Kula, Kaua‘i. Mānoa Valley. A gregarious species, the Alexandra palm has a solitary, slender, smooth, whitish trunk topped by a crown of gracefully spreading pinnate leaves, which are ashy gray on the underside, supported by a green crownshaft. The small red fruits occur in abundance on pendulous strands held below the leaves. The Chinese fan palm (Livistona chinensis) occurs as scattered individuals in the Ko‘olau Range on O‘ahu, in ‘Īao Valley on Maui, and along gulches on Kaua‘i (fig. 244). On O‘ahu, it occurs in the Nu‘uanu Valley and adjacent areas east of downtown Honolulu. Its solitary brownish trunk holds a crown of spreading, fan-shaped leaves with spiny leaf stalks and pendulous segment tips. Flower stalks emerge from among the leaves and eventually hold bunches of metallic bluish green fruits. Like the Chinese fan palm, the Cuban or Florida royal palm (Roystonea regia) occurs as scattered individuals in the lower reaches of the Ko‘olau Range on O‘ahu but is likely to occur elsewhere in Hawai‘i because it naturalizes so readily (fig. 245). Like the Alexandra palm, the Cuban royal palm has a solitary, smooth, white trunk topped by a crown of spreading pinnate leaves, which are green on the underside, supported by a green crownshaft, and its flower and fruit stalks are held below the leaves. The Cuban royal palm differs, though, in its larger trunk, plumose (leaflets arranged in several planes rather than flat) leaves, and purplish red fruits. The South American royal palm 165 Appendix 3 FIGURE 245.Y;  #/  3‘ahu. (R. oleracea), perhaps naturalized in Hālawa Valley on O‘ahu and elsewhere, is similar to the Cuban royal palm but differs in its larger trunk that is uniform in diameter throughout its length and in its leaves not hanging below the horizontal. Often forming dense, impenetrable thickets, the wild date palm (Phoenix sylvestris) has naturalized in brush and shrubby areas on the northern and eastern shores of O‘ahu as far south as Kāne‘ohe, as well as on western Kaua‘i (figs. 246 and 247). Popular with landscapers, the wild date palm has a solitary brownish trunk covered with rough, persistent leaf base stubs and a crown of spreading, slightly plumose, pinnate leaves with rather stiff pinnae. Like all date palms, the lower pinnae are modified into hard, stiff, very sharp spines. Flower stalks emerge from among the leaves and eventually hold the ripened bunches of purplish brown fruits. Appendix 3 166 A vigorously growing, highly adaptable species, the Mexican fan palm (Washingtonia robusta) is the signature and iconic palm of Southern California and has naturalized in the Wai‘anae and Hawai‘i Kai–Koko Head areas of O‘ahu (figs. 248 and 249). Officially listed as an invasive species in Hawai‘i and California, it grows rapidly to 75 feet tall or more and has a compact crown of bright, glossy, green leaves with pendulous tips, spiny leaf stalks, and long, pendulous, flower and fruit stalks that typically extend well beyond the leaves. The trunk may be covered for a considerable distance, especially in wind-protected locales, with a persistent “skirt” of old dead leaves, which may eventually fall or weather away to leave a smooth brown...