Thick-leaved Mahoe (Melicytus crassifolius)

A Pacific Plant Promotion

By: Richie Steffen

Richie Steffen is curator of horticulture for the Elisabeth C Miller Botanical Garden in Seattle, where he manages the rare…

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Thick-leaved mahoe (Melicytus crassifolius) is a dense, compact shrub native to New Zealand. Photo: Richie Steffen

Thick-leaved mahoe (Melicytus crassifolius) is a dense, compact shrub native to New Zealand. Photo: Richie Steffen

The flora of New Zealand comprises a collection of exciting and bizarre plants for gardeners in the Northern Hemisphere; a great example of this is the genus Melicytus. These woody members of the violet family (Violaceae) can range from small shrubs to trees and occur primarily in New Zealand with a few in Australia, Fiji, Norfolk Island, and the Solomon Islands.

One of the hardiest and toughest members of the genus is Melicytus crassifolius. The botanical name Melicytus, which roughly translates to “honey basket” or “honey receptacle,” refers to the tiny, nectar-filled flowers. The species name crassifolius means “thick-leaved,” aptly describing the waxy, leathery leaves and provides reasoning for the common name thick-leaved mahoe.

Detail of white fruit on Thick-leaved mahoe (Melicytus crassifolius) Photo: Richie Steffen

Detail of white fruit on Thick-leaved mahoe (Melicytus crassifolius) Photo: Richie Steffen

Thick-leaved mahoe is native to both the North and South Islands of New Zealand where it is typically found along coastal lowlands in open scrub areas, cliff faces, stable sand dunes, and gravelly river flats. In the landscape, it grows as a compact shrub with heavily-branched, arching, greenish-tan stems that taper at the tips to a sharp point. Although they are not as prickly as a barberry or rose, the plants are amply armed to warrant care when handling. Tightly bunched along the twigs, the small, evergreen, teardrop-shaped leaves are bright olive green with a soft glossy tone. Inspring, small greenish lemon-yellow flowers cluster along the branches followed in late summer by bright white berries that are about the size of a pea. The berries last from late summer until early winter, often developing an unusual steel-blue spot with age.

Melicytus crassifolius is easy to grow and thrives on neglect once established. The hardiness of this shrub is poorly accounted for in literature and is mostly assumed to only be hardy in USDA zones 9 and 10. The seedlings grown for this distribution are from a plant that has survived at the Miller Garden in Seattle, Washington, for more than 30 years. This particular shrub has survived temperatures as low as 12°F to 15°F and regularly experiences winter temperatures in the low twenties and upper teens, safely making this selection hardy to at least USDA zone 7b and perhaps lower.

Thick-leaved mahoe prefers full sun but will tolerate light to open shade, if it receives at least three to four hours of direct sun and is not crowded by low overhead branches. It is fairly adaptable to most garden soils with the exception of heavy clay, thriving in sandy and rocky soil and drought tolerant in all but the most extreme conditions. Good drainage is required for a strong root system to develop. Thick-leaved mahoe tolerates salt spray and windy conditions becoming a tight, dense plant over time. Height at maturity varies from three to five feet; the Miller Garden specimen is about three feet tall.