Common Name: Shell Ginger
Origin: Eastern Asia
Features/Uses: Alpinia zerumbet is called Shell Ginger because of the way each individual flower resembles a sea shell. Most plants in the Zingiberaceae family have flowers that rise directly from the rhizomes, but in this species long drooping racemes of flowers emerge from the ends of 8’ tall stalks, putting the fragrant light pink flowers at just about nose height. Certain varieties have been selected for variegated leaves with an electric combination of green and yellow stripes.
Growth Habit: Shell Ginger spreads slowly by rhizomes just below the surface of the soil. Individual shoots grow somewhere between 2’ and 10’ tall depending on the variety and environment. In colder areas or exposures the plants may disappear into dormancy during the winter. Protected spaces at the San Diego Botanic Garden allow Alpinia zerumbet to grow year-round. Plants flower on second year growth, making them mainly used as foliage plants in cooler areas.
Bloom Time: Mature plants bloom reliably throughout the summer and sporadically at other times of year.
Cultural Requirements: Plant grow best in organically rich soil with consistent moisture levels. Though tolerant of a wide range of lighting conditions, from mostly shade to full sun, plants do best in San Diego in light shade. Poor water quality and low nutrient levels in the soil can limit growth of this plant, but they’re otherwise fairly low-maintenance plants. Prune as needed either to control the size or clean out stalks that have already flowered. Plants bloom on second year growth, so areas cold enough to consistently force dormancy may not see flowers. In colder regions of Southern California, a think layer of organic mulch over dormant rhizomes will help protect them from winter lows and contribute nutrients for the following season.
Where in the Garden: Palm Canyon, Bamboo Garden, Herb Garden
Photos: Rachel Cobb and Lisa Reynolds