Hibiscus arnottianus, commonly known as White Rosemallow, is a captivating flowering shrub native to the Hawaiian Islands. This species holds significance within its native ecosystem and is appreciated for its striking floral displays. The White Rosemallow is an erect, evergreen shrub that typically reaches a height of 2 to 4 meters, though it can occasionally grow taller. Its growth habit is generally open and somewhat spreading. The leaves are ovate to broadly ovate, with a length of 7 to 15 centimeters and a width of 5 to 12 centimeters. They are typically palmately lobed, usually with three to five lobes, and possess a serrated margin. The upper surface of the leaves is a medium to dark green, while the underside is often paler and may be covered in fine hairs. The bark is smooth and grayish-brown. The most prominent feature of Hibiscus arnottianus is its large, showy flowers. These are typically solitary, borne in the leaf axils. The flowers are predominantly white, often with a pale pink or reddish blush at the base of the petals. Each flower can measure 10 to 15 centimeters in diameter and features five broad, delicate petals. A distinctive characteristic of the flower is its prominent staminal column, which is usually a contrasting color, often deep red or maroon, and extends beyond the petals, bearing numerous yellow anthers. The flowers are fragrant, emitting a sweet, pleasant scent, particularly in the morning. Following pollination, the plant produces a capsule fruit, which is ovoid and typically 2 to 3 centimeters long, containing several seeds. Hibiscus arnottianus is endemic to the Hawaiian Islands, where it is found in dry to mesic forests and shrublands. Its natural habitat is characterized by well-drained soils and a climate with distinct wet and dry seasons. While it thrives in its native environment, it is also cultivated in suitable climates as an ornamental plant. It prefers full sun to partial shade and well-drained soil. Regular watering is beneficial, especially during dry periods, but the plant is relatively drought-tolerant once established. It is sensitive to frost and is best grown in tropical and subtropical regions or protected environments in cooler climates. The ecological role of Hibiscus arnottianus includes providing nectar for native pollinators. Ornamentally, its large, fragrant white flowers and attractive foliage make it a desirable addition to gardens, particularly in regions where it can thrive outdoors. Its significance is primarily horticultural and ecological within its native range.