About 15 woody plant species form the genus Cordyline. While botanists and horticulturists typically refer to the plants by their scientific names, laypersons often use names like cabbage trees, lily trees, or ti trees to refer to members of this genus.
Restricted to the Southern Hemisphere, most forms are native to Australia and the Southeast Asian archipelago. However, one species – Cordyline sellowiana — is instead native to Brazil and Bolivia. Some species have become established outside of their native range, such as the good luck plant (Cordylinefruticosa), which now grows in Hawaii.
Members of the genus are all monocots, meaning that they have parallel leaf veins (as grasses, lilies and true palms do) and their seeds bear only a single embryonic leaf, or cotyledon. Some species exhibit a distinctly tree-like growth habit, although a few members are better described as shrubs. None grows very tall; the largest individuals of the largest species rarely eclipse 15 feet in height.
Habitat Preferences
Most Cordyline trees are adapted for damp habitats. For example, Cordyline rubra – often called the palm lily in its native Australia – grows throughout the rainforests and mesic eucalyptus forests of the east coast. Similarly, palm lilies (Cordyline cannifolia) and broad-leaved palm lilies (Cordyline petiolaris) are also adapted to living under damp forest canopies, while narrow-leaved palm lilies (Cordyline congesta) typically grow near the edges of rainforests.
However, a few forms can adapt to drier habitats. Mountain cabbage trees (Cordyline indivisa) are most comfortable in damp forests, but they extend into the drier surrounding regions of their New Zealand homeland. At the other end of the spectrum, Three King cabbage trees (Cordyline obtecta) are more common in dry, sunny areas, and they fail to thrive in damp soil. The tiny dwarf cabbage tree (Cordyline pumilio) – which grows more like a sedge-like shrub than a tree –grows in drier scrublands and open-canopied forests.
Cultivation and Horticultural Use
Several members of the Cordyline genus appear in horticultural markets. Most are rather hardy species that require relatively little care. However, these plants are adapted to warm climates; few – if any – of these species tolerate frost. Horticulturists have produced cultivars of several members of the genus, including three King cabbage trees and good luck trees.
Broad-leaved palm lilies are common houseplants, although they also grow well in semi-shaded gardens with ample soil moisture. By contrast, the narrow-leaved palm lily (Cordyline stricta), which is one of the largest members of the group, is primarily used outdoors in screening applications. Narrow-leaved palm lilies are well suited for growing indoors or outdoors, as they adapt well to most growing conditions.
Food for Thought
Some species produce starchy rhizomes, which humans have used as a food source for thousands of years. The Maori people would cook the rhizomes to extract the sugar from them, while some Hawaiians ferment the rhizomes to produce a liquor. The leaves of the trees and shrubs were also used to thatch roofs or make clothing.
Many of the species produce attractive berries that vary from black to blue to red in color. These fruits not only provide aesthetic benefits, but they also serve as a food source for songbirds. Additionally, several of the species play a role in the lifecycles of local caterpillars.