Dwarf umbrella plant or Hawaiian schefflera (Schefflera arboricola) may also simply be called "arboricola" at a tropical plant nursery. Grow it as a tropical hedge outdoors in frost-free regions (USDA Hardiness Zones 10 and warmer) or as a bushy potted house plant elsewhere. This evergreen shrub potentially grows 10 to 20 feet tall and nearly as wide, and it responds well to occasional stem pruning.
Adaptable to a wide range of light exposures, Hawaiian schefflera grows best with no more than six hours of daily sunlight. In interiors, bright indirect light works well, and it acclimates to even dimmer light, as long as the soil remains on the dry side. Providing any amount of sunlight for no more than 6 hours allows for retention of leaves and prevention of sun scald on foliage, especially on varieties with variegated coloring. In the tropical garden, use it as a shady hedge plant under evergreen trees or foundation beds. In hot summer regions or in drier, sandy soils, shade from the intense midday sun proves best.
The key to a healthy Hawaiian schefflera is well-draining soil. It does best in sandy or loamy soils with organic matter incorporated; avoid heavy clay or compacting soils that impede water drainage. Soil pH tolerance includes slightly alkaline and mildly acidic types. Regardless of where the plant is grown, the soil must never become or remain soggy after rains or watering, which promotes root and stem rot. Overall, a moist to slightly dry soil works best for this shrub.
Don't over-water. Supply about 1 inch of water (either irrigation or natural rainfall) to the Hawaiian schefflera each week during the growing season from spring to early fall. Water more frequently in sandy soils or in hot weather. In general, allow the soil's top inch to become dry before another watering. In winter, reduce watering frequency so that 1 inch of water is supplied every 10 to 21 days.
Hawaiian schefflera does not need a lot of fertilizer to look good and grow with health. Use a well-balanced liquid fertilizer according to product label directions as part of watering only during the spring and summer months. Stop fertilizing in autumn and winter when sunlight intensity wanes. Alternatively, scatter granules of a slow-release fertilizer over the root zone in spring. Outdoor plants may only need a fresh application of compost or well-cured manure in spring to sustain good growth and flowering.
When stems become leggy or awkward in shape, or to rejuvenate the shrub, cut back stems with pruners in spring. New grow tips will sprout from the area just below the pruning. Prune off flowers or fruits as needed, or if they become unsightly.
Schefflera arboricola is usually free from pests and diseases. Monitor foliage and stems for scale insects and spider mites. Scale often results when plants receive too little light, and spider mites when air is dry and there is little air movement. Outdoor plants exposed to cold, dry winter winds often drop foliage in excess. Indoors, avoid placing the containerized Hawaiian schefflera in the drafts of heating and air-conditioning vents.