Sida fallax aka Yellow Ilima

Sida fallax, or ilima, belongs to the mallow family, Malvaceae. It is native to Hawaii and other Pacific islands. Kew places it in the seasonally dry tropical biome. In Hawaii, it grows on rocky shores and sandy coasts. It also occurs on limestone reefs and lava fields. Inland habitats include pastures, scrub, and wooded areas. Its flowers serve as the official flower of Oahu.

This broadleaf evergreen can form a subshrub or shrub. Its shape varies from low ground cover to tall shrubs. Coastal plants may stand just 0.5–1 foot [0.15–0.30 metres] high. These low forms grow in dry sites near the sea. The listed mature height reaches 10 feet [3.05 metres]. Plants can spread to 8 feet [2.44 metres]. This range of forms affects how gardeners can use it. The evergreen leaves also give the plant winter interest.

The showy flowers are most often yellow. Some have maroon centres, while others show shades of orange. Dull red flowers also occur, and green flowers are rare. The source lists seasonal bloom rather than fixed flowering months. People use the yellow flowers to make leis. This use gives the plant a place in Hawaiian culture. The supplied evidence does not establish edible parts or toxicity. Its use in leis alone does not establish food safety.

Grow ilima in full sun and soil that drains well. A gritty soil with dry to moderate moisture suits it. Avoid heavy clay, which does not meet its drainage needs. The plant tolerates dry soil and shallow, rocky ground. It is winter hardy in USDA zones 10–11. Its low care needs suit gardens within that warm range. Use low forms as a spreading ground cover. Shrubby forms can make hedges, screens, or single accents. It also suits containers and areas managed for natural growth.

Serious pest and disease problems are not usually reported. Still, ants, aphids, mealybugs, scale, and slugs may appear. Gardeners should also watch for red spider mites. Too much shade or soil moisture can lead to disease. Under those conditions, shrubs may develop rust or black sooty mould. Sun and good drainage therefore matter when choosing a planting site.