Hibiscus arnottianus

Common Names

Koki'o Ke'oke'o, Hawaiian White Hibiscus, Hau Hele, O'ahu White Hibiscus, Pamakani, Koki'o Kea, Arnott's Hibiscus, Moloka'i White Hibiscus

Summary

The Hawaiian white hibiscus is a Hawaiian native shrub or small tree in the Malvaceae family, evergreen with leathery oval leaves and showy white flowers that are often fragrant; flowers are solitary at branch ends, with a red-centered staminal column in subspecies arnottianus and punaluuensis, while subspecies immaculatus has a white column; native to wet to mesic forests on Molokaʻi and Oʻahu, it blooms year-round.

Cultivation favors well-drained soils with moisture and full sun to partial shade, tolerating drought if soil drains well; prune lightly and fertilize with a low-phosphorus mix (2-1-3 or similar) while monitoring for pests such as sucking insects and leaf spot. Propagation is from seeds (easy from fresh seed, but prone to hybridizing) with hand pollination recommended; seeds about 1/8 in; germination typically 2–3 weeks; also possible via semi-hardwood cuttings (4–6 in, <1/2 in diameter) with rooting hormone, high humidity, and 2–5 months to root; air layering or grafting onto common rootstocks are feasible. Uses include landscape features such as specimen plants, hedges, screens, or containers.

Lifecycle

Perennial

Height

15-30 ft

Spread

20-25 feet

Hardiness Zones

Zones 9-11

Sunlight Requirements

Ideally full sun, tolerates partial sun to partial shade.

Soil Type

Well-drained, slightly acidic loamy soil rich in organic matter

Soil Drainage

Well-drained

Soil pH

6.0-6.5, slightly acidic

Bloom Color

White

Bloom Time

Year-round

Foliage Color

Green

Fall Foliage Color

Green

Leaf Lifecycle

Evergreen broadleaf

Growth Rate

Moderate growth

Seasons of Interest

Spring, Summer, Fall, Winter

Propagation Methods

Seeds, Cuttings, Air layering, Grafting

Attracts Wildlife

Attracts bees, moths, and birds