pronounced: hed-EE-kee-um kor-on-AIR-ee-um
Hedychium is from the Greek, 'ηδυς (hédys), sweet, and χιον (chion), snow; coronarium is Latin, coronarius, of/for wreaths, garlands. The plant is native to China, Taiwan, Myanmar and the Indian sub-continent, but is now naturalized globally, including in eastern Australia. southern Africa, south-eastern USA, Central America, and many islands with warm climates. It has become invasive in many areas.
The plant can be found in shaded or semi-shaded areas, particularly those that become waterlogged, along river banks and in shallow water, but not where it can become totally submerged. It can form intensive thickets, replacing native plants. It has the potential to be a significant environmental weed in the sub-tropical and even in the temperate regions of Australia, especially in south-eastern Queensland and on the north coast of NSW.
It is a perennial herbaceous plant usually growing 1 – 2 m tall, and occasionally up to 3 m. It grows from a thick mat of rhizomes close to the surface of the soil. The rhizomes persist, but the upright stems usually die off annually. Reproduction is mainly from these rhizomes, but the plant can also produce seeds. These seeds have a red aril that attacts insects, which are thought to disperse some of the seeds; the others are mostly dispersed by birds. The rhizomes are edible, and also have medicinal qualities, but this does not compensate for the environmental damage the spread of the plant can produce.
The large leaves (20 - 60 cm long by 4 - 10 cm wide) are alternate, lanceolate to oblong-lanceolate, with entire margins and acuminate tips. Where the leaf-sheath meets the leaf blade there is a ligule 2 - 3 cm long. The upper surfaces of the leaves are glabrous, and the lower surfaces finely pubescent.
The attractive flowers are borne in dense spike-like clusters anything up to 20 cm long at the tips of the stems. The flowers are white, with 3 large inner tepals that are fused together at the base into a narrow tube 6-9 cm long. Their lobes are linear or lanceolate, and 3 - 5 cm long. There is also a cordate labellum, white with a cream to yellow base. The greenish sepals are fused into a tube, split on one side.There are 2 staminodes and a single large stamen. This stamen is carried on a filament about 3 cm in length, and has a pale yellowish anther. Flowering can occur throughout the year, but is mostly seen during summer and autumn.
The fruit is an oblong capsule with 3 compartments; but the fruits are rarely seen in Australia.
Mechanical control is very difficult, as any portions of the rhizomes left in the ground will regenerate. Foliar spraying is more effective, but it needs to be carried out several times.
The medicinal qualities of the rhizome, mentioned above, are said to be antirheumatic, excitant and tonic. An essential oil from the rhizomes is said to be carminative, and is also used against parasitic worms. The seeds are used as a carminative and a stomachic.