Hedychium gardnerianum
Encyclopedia
Hedychium gardnerianum (Kahili Ginger, Ginger Lily (Aust.)) is a plant
native to the Himalayas
in India, Nepal, and Bhutan. It grows to 8 ft tall with long, bright green leaves clasping the tall stems. The very fragrant pale yellow and red flowers are held in dense spikes above the foliage. They appear towards the end of summer.
species as an ornamental plant
in gardens and parks. It prefers a warm tropical climate, although it can thrive in sub-tropical and temperate regions by tolerating light, infrequent frosts.
The plant is a serious invasive species
in certain areas. It is known as 'wild kahili ginger' and is listed as a weed of concern on conservation land in New Zealand
, Hawaii
and the Azores
.
It has been recognized as one of "The World's 100 Worst Invasive Alien Species" by the IUCN Invasive Species Specialist Group (ISSG).
.
In tropical
, or sub-tropical climates
however, Hedychium gardnerianum can quickly colonise untended areas. Its sticky seeds are easily spread by birds and roaming mammals, while rhizomes crowd out native seedlings by forming dense mats. Without human intervention, it can colonise large areas quickly as each rhizome adds at least one segment per season depending on climatic and light conditions.
The methods mentioned above may give some control over any particular clump but will not resolve the problem. Each year, Hedychium gardnerianum's rhizomes increase the surface area of a particular area, whether the flowers are removed or not. Complete removal of the rhizomes or poisoning
, (usually before flowers are matured), is the only certain way of controlling the plant if it is considered a weedEven so, annual follow up is required for some years to ensure re-infestation should be done when Hedychium gardnerianum is particularly virulent. Re-infestation may occur from spreading by neighbouring plants, or dormant seeds disturbed by the removal of the original tuber clump as seeds remain viable for 2-4 years. Lifted rhyzomes should be removed from site as if left in contact with soil they will restore themselves.
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
native to the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
in India, Nepal, and Bhutan. It grows to 8 ft tall with long, bright green leaves clasping the tall stems. The very fragrant pale yellow and red flowers are held in dense spikes above the foliage. They appear towards the end of summer.
Cultivation
Hedychium gardnerianum is the most widely cultivated HedychiumHedychium
Hedychium is a genus of perennial plants native to tropical Asia and the Himalayas, commonly growing to between 120 and 180 cm tall. Common names include garland flower, ginger lily, and kahili ginger...
species as an ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
in gardens and parks. It prefers a warm tropical climate, although it can thrive in sub-tropical and temperate regions by tolerating light, infrequent frosts.
The plant is a serious invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in certain areas. It is known as 'wild kahili ginger' and is listed as a weed of concern on conservation land in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
.
It has been recognized as one of "The World's 100 Worst Invasive Alien Species" by the IUCN Invasive Species Specialist Group (ISSG).
Control as a Weed
In areas where Hedychium gardnerianum is not of a concern, it may still require control depending on the environment, and its potential as an invasive species in the long term. The simplest way to reduce spread is monitoring. Removal of flower heads before they set seed, and monitoring spread of the rhizomes in these situations will enable Hedychium gardnerianum to be managed in cooler temperate climates such as in the United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
.
In tropical
Tropical climate
A tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures above...
, or sub-tropical climates
Subtropics
The subtropics are the geographical and climatical zone of the Earth immediately north and south of the tropical zone, which is bounded by the Tropic of Cancer and the Tropic of Capricorn, at latitudes 23.5°N and 23.5°S...
however, Hedychium gardnerianum can quickly colonise untended areas. Its sticky seeds are easily spread by birds and roaming mammals, while rhizomes crowd out native seedlings by forming dense mats. Without human intervention, it can colonise large areas quickly as each rhizome adds at least one segment per season depending on climatic and light conditions.
The methods mentioned above may give some control over any particular clump but will not resolve the problem. Each year, Hedychium gardnerianum's rhizomes increase the surface area of a particular area, whether the flowers are removed or not. Complete removal of the rhizomes or poisoning
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
, (usually before flowers are matured), is the only certain way of controlling the plant if it is considered a weedEven so, annual follow up is required for some years to ensure re-infestation should be done when Hedychium gardnerianum is particularly virulent. Re-infestation may occur from spreading by neighbouring plants, or dormant seeds disturbed by the removal of the original tuber clump as seeds remain viable for 2-4 years. Lifted rhyzomes should be removed from site as if left in contact with soil they will restore themselves.