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Zingiber zerumbet

Shampoo ginger

Zingiberaceae India and Southeast Asia

Attracts Pollinators Fragrant (moderate)Container Friendly

SunPart Shade – Full Shade

WaterMedium

HardinessZones 8–11

Overview

Zingiber zerumbet is a deciduous rhizomatous perennial with leafy stems 3-6 feet (1-2 m) tall forming clumps 2-4 feet (0.6-1.2 m) across. Leaves are lanceolate, 8-12 inches (20-30 cm) long, stalkless, and set in two ranks along the stem. The inflorescence rises on its own short stalk 6-12 inches (15-30 cm) tall directly from the rhizome, separate from the leafy shoots, and forms a cone of overlapping bracts 2-4 inches (5-10 cm) long. The cone opens green and ripens to scarlet across 4-6 weeks, filling with a clear slimy mucilage that is squeezed out and used as a hair rinse. Small pale yellow-white flowers push out between the bracts a few at a time. Top growth yellows and dies back in the cool or dry season, and the clump regrows from the rhizome the following spring. Rhizomes are aromatic and contain zerumbone. The species spreads by rhizome and by cones that root where they fall, and it forms dense stands in Hawaiian mesic forest, where it is managed as a weed in conservation areas.

Native Range

Zingiber zerumbet is native to India and Southeast Asia, with a natural range extending from the Western Ghats through Indochina to Malesia in moist forest understorey below 4,000 feet (1,200 m). Polynesian voyagers carried rhizomes across the Pacific, and the plant has been present in Hawaii since before European contact. It is now naturalized through the humid tropics and subtropics, including Fiji, Hawaii, and parts of the southern United States.

Suggested Uses

Grown in shaded borders, woodland gardens, and container plantings at spacings of 2-3 feet (0.6-0.9 m), and under glass in cooler climates. Cones are cut for arrangements at the green-to-red stage and hold 7-10 days in water. The mucilage from ripe cones is used as a hair and scalp rinse, and the rhizome is used as a flavouring and in traditional Hawaiian and Southeast Asian medicine.

How to Identify

The flowering cone appears on a short leafless stalk at ground level, separate from the leafy stems, which sets Zingiber spp. apart from Hedychium spp. and Alpinia spp. that flower at the shoot tip. A mature cone is barrel-shaped, 2-4 inches (5-10 cm) long, and releases clear mucilage when squeezed. Leaves are stalkless and two-ranked, 8-12 inches (20-30 cm) long, with a hairless upper surface. Broken rhizomes smell sharply of ginger with a bitter edge.

Appearance

Size & Dimensions

Height3' - 6'

Width/Spread2' - 4'

Reaches mature size in approximately 3 years

Colors

Flower Colors

red

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Summer Fall

Cones emerge from June through October, several weeks after the leafy shoots reach full height. Each cone holds on the plant for 8-12 weeks, turning from green to scarlet as it matures, and a clump produces 5-20 cones a season. The small yellow-white true flowers open two or three at a time and last a single day. Cones fall in late autumn and root where they land in moist litter.

Detailed Descriptions

Flower Description

Pale yellow-white flowers emerging from green-to-scarlet bracts

Foliage Description

Mid green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam silt peat

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years to full clump size

Care & Maintenance

Care Guide

Zingiber zerumbet grows in dappled to half shade with 2-6 hours of filtered sun, in humus-rich loam or silt at pH 5.5-7.0 held evenly moist through the growing season. It takes 50-100 inches (1,250-2,500 mm) of annual rainfall or the irrigation equivalent while in leaf, and watering is cut back sharply once the foliage yellows in autumn, since wet dormant rhizomes rot. Rhizomes survive to USDA zone 8 under 4-6 inches (10-15 cm) of mulch, while top growth is destroyed by the first frost. A balanced fertilizer at 2-3 ounces (55-85 g) per clump in spring and again at midsummer sustains the season growth. Full sun scorches the leaf margins in hot dry climates. Root-knot nematode and Pythium spp. rhizome rot are the recurring problems in wet, poorly drained soil.

Pruning

Dead stems and spent cones are cut to ground level after the foliage yellows, between November and January in subtropical gardens. Cutting green stems mid-season lowers the following year rhizome reserves and cone count. Clumps are divided every 3-4 years at the end of dormancy, splitting the rhizome into sections carrying 2-3 growth buds. Rhizomes running beyond the clump edge are severed with a spade to hold the spread.

Pruning Schedule

fallwinter