Hedychium gardnerianum
kahili ginger
Eastern Himalayas; naturalised widely
Overview
Hedychium gardnerianum is a large rhizomatous perennial in the ginger family Zingiberaceae, forming dense clumps of upright leafy canes 5-8 feet (1.5-2.5 m) tall. The smooth, paddle-shaped leaves are 8-18 inch (20-45 cm) long and arranged in two ranks along the canes. In late summer and autumn each cane is topped by a cylindrical flower spike 10-18 inch (25-45 cm) long, packed with pale lemon-yellow flowers that have long, protruding red stamens and a strong sweet fragrance. Red-coated seeds in orange capsules follow in warm climates. Hedychium gardnerianum is native to the Himalayas but has naturalised widely in mild, moist regions, where its thick mat of rhizomes and bird-spread seed let it form dense stands that crowd out other plants; it is a declared environmental weed in parts of eastern Australia and on many islands. It spreads from both rhizome fragments and seed, is frost-tender, and dies back where winters are cold. The heavy rhizome mat resists removal once it is established.
Native Range
Hedychium gardnerianum is native to the eastern Himalayas, including parts of northern India, Nepal, and Bhutan, where it grows in moist montane forest. It has naturalised in many mild, humid regions worldwide and is listed as an environmental weed in parts of eastern Australia, New Zealand, Hawaii, and the Azores.Suggested Uses
Hedychium gardnerianum is grown as a fragrant ornamental in frost-free gardens outside its weedy range, where its scented flower spikes are used in moist, sheltered beds. Within its naturalised range it has no garden planting use and is managed as an environmental weed, with removal and replacement by local species the usual approach.How to Identify
Appearance
Size & Dimensions
Height5' - 8'
Width/Spread3' - 6'
Bloom Information
Flowering occurs in late summer and autumn, around February to May in its naturalised southern-hemisphere range. The pale yellow, red-stamened flowers are strongly fragrant, mainly in the evening, and are visited by moths and birds. Orange seed capsules with red-coated seeds form afterward in warm climates and are spread by birds.
Detailed Descriptions
Flower Description
Pale yellow with red stamensFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 3-8 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
Care & Maintenance
Care Guide
Hedychium gardnerianum grows quickly in warm, frost-free to lightly frosted climates on moist, fertile soil in part shade to full sun, and it spreads strongly once settled. Because it is a declared environmental weed in parts of Australia and elsewhere, it is not planted in gardens within its naturalised range, and its sale and movement are restricted under weed laws in several regions. Where it is already present, control means digging out the whole rhizome mat or cutting and treating the cut surfaces, since fragments left behind regrow. Removing flower spikes before seed sets reduces bird-spread seedlings. Repeated follow-up over several seasons is needed to exhaust the rhizomes and seed bank.Pruning
In a garden sense pruning is limited to removing spent canes and old flower spikes at the base. Within its naturalised range, cutting spikes before the seed ripens limits spread, and frost-killed top growth can be cleared in late winter. Management is otherwise rhizome removal rather than shaping.Container Growing
✓ Suitable for container growing
Minimum container size: 10 gallons