This article, with more photos, appeared in the May/June Issue of Hawaii Landscape
By Orville C. Baldos, CTAHR
Department of Tropical Plant and Soil Sciences
In recent years, the promotion and use of native plants as ornamentals has increased steadily in both local and national levels due to growing awareness of water use issues, biodiversity conservation, invasive species spread, storm water management and the need to provide suitable habitats for pollinators and other wildlife. In Hawaii, the use of native plants in landscaping projects has tremendously increased since the first efforts to promote native plants in public landscaping was passed into law in 1992. Today, native plants such as naupaka (Scaevola taccada), ‘uki‘uki (Dianella sandwicensis), pohinahina (Vitex rotundifolia), O’ahu sedge (Carex wahuensis), ‘ilima (Sida fallax), ilie’e (Plumbago zeylanica) and ‘akia (Wikstroemia uva ursi) have become commonplace in many installed designs.
Despite the widespread use and acceptance of native Hawaiian plants in landscaping, there is still a very limited number of species/selections available at many nurseries. The lack of variety in native plants used in landscaping is partly due to the limited information on propagation, proper care, and maintenance of a number of species. In the next 15 years, demand for native Hawaiian plants is expected to increase due to recent amendments to HB206/SB435, a state bill aiming to gradually increase the footprint of native plants in public landscaping from 10 percent by 2019 to 35 percent by 2030.
In order to increase the variety and availability of native Hawaiian plants, a research program was initiated to collect, select, develop and package common and non-endangered plants for landscape and other uses such as potted flowering plants, indoor plants and cutfoliage. Native Hawaiian plants that are currently being studied for expanded ornamental use include Carex spp. (indoor and landscape use), ala ala wai nui (Peperomia spp.) (indoor use), aweoweo (Chenopodium oahuense) (landscape and container use), Eragrostis spp. (landscape and container use) and ilima (Sida fallax) (landscape and potted flowering plant use). Seeds and cuttings of plants exhibiting ornamental characteristics (e.g. unusual leaf shape and size, variegation, unusual growth, large flowers, free-flowering habit) are currently being collected and propagated for landscape, potted flowering plant and indoor plant evaluation. Development of new selections are also being done through controlled pollination between plant selections. Propagation techniques such as the use of rooting hormones to increase rooting of cuttings and division for each species will also be refined. Promising selections will be evaluated at different locations (plants for landscape use, potted flowering plant) and under indoor conditions (plants for indoor/houseplant conditions). Promising selections together with the production protocols and maintenance notes will be prepared prior to native cultivar release within the next 3 years. Hopefully, with the increase in availability and variety of native Hawaiian plants in our landscapes and interiors, tourists and locals alike can appreciate the beauty and value of Hawaii’s unique flora.
This work is supported by the USDA National Institute of Food and Agriculture, Hatch projects HAW08040-H, managed by the College of Tropical Agriculture and Human Resources