Ginger lilies are large, exotic perennials. Their native range extends from Madagascar through southern China and tropical Asia. Ginger lilies have been widely introduced to Central and South America, South Africa and eastern Australia. Some species have also become pests, naturalising and overwhelming the native flora. In Hawai’i, Hedychium gardenerianum has become invasive on the island, with birds spreading the seed throughout the forests.
There are about 100 species belonging to the genus. All ginger lilies are rhizomatous and can form large clumps, with some species reaching more than two metres in height. The spear-shaped leaves are arranged in two ranks, clasping the erect stems. Dense terminal spikes of often-fragrant flowers are sometimes in clusters of more than fifty flowers. The generic name Hedychium is derived from two Greek words, hedys meaning ‘sweet’ and chios meaning ‘snow’.
Ginger lilies gained popularity in Europe during the Victorian era, grown in glasshouses as tender hothouse plants, well protected from European winters. In temperate regions and milder parts of the United Kingdom, many species are now known to be hardy in cultivation. Several Hedychium species grow at the Botanic Garden.
Four species and their cultivars do particularly well in British gardens. Hedychium densiflorum is hardy to -18 degrees Celsius, and produces terminal spikes, densely cloaked in beautiful coral-orange flowers. Hedychium gardnerianum is one of the hardiest species coming from altitudes of up to 2000 metres above sea level. It can grow to more than two metres, bearing spikes more than thirty centimetres long, smothered in pale yellow, lightly scented flowers. From Assam, Hedychium greenii has large, red-orange flowers, which combine with striking, two-tone leaves, green with dark red undersides. Curiously, the species produces plantlets on old flowering stems, a trait known as vivipary. Although Hedychium spicatum is another very hardy species, it is always deciduous in cultivation, with short stems bearing delicate, arching salmon-pink and yellow flowers.
In temperate gardens, the rhizomes benefit from a layer of winter mulch. Ginger lilies are slow into growth in spring but respond well to the nutritional boost they receive as mulch decomposes.
In the wild, these plants grow at forest margins and in moist places, sometimes scrambling over rocks or running along the banks of streams. In cultivation, recreating such conditions gets the best results. Grown in a sheltered spot with filtered sunlight and moisture-retentive soil, gardeners are rewarded with extravagant, fragrant flowers in late summer.