Cordyline (Botanical Name: C. terminalis) are common decorative plants that thrive outdoors in hardiness zones 9 to 12, but also make excellent houseplants. The name Cordyline originates from Greek; the word kordyle, meaning "club," is a reference to the plant's enlarged underground stems. Cordyline typically has leathery leaves shaped like a spear or lance with a variety of coloring including green, red, yellow, white, purple, and purplish-red. Caring for these plants indoors is simple and straightforward, but they must be kept warm and they need a lot of light.
Some species in this group have fragrant flowers followed by berries. The plant will produce white to pale lavender flowers that are cup-shaped and sweet-smelling. They bloom in early summer and then small berries will appear after the flowers. It's more typical for flowering to occur in outdoor varieties, but flowers can appear on houseplants. They are, however, prone to some problems and pests; the most common are scale insects, spider mites, and mealybugs. Also, bacterial and fungal spots, bacterial soft rot, and root rot can also occur on these plants.
Cordyline needs bright light, but avoid direct sunlight in unhabituated plants. Also, green-leaved cordyline tends to do best with direct light, while those with other colored leaves may prefer bright indirect or filtered sunlight.
Cordyline needs a rich, well-drained high-quality potting mix with a pH of 6 to 6.5. If you move the plant outdoors during warmer months, make sure the outdoor soil drains well and any threat of frost has passed. Outdoor plants also need to be well secured; with its large leaves, they can catch in the wind and topple over.
Water and Fertilizer
It is important to keep the soil continuously moist. Reduce watering during the winter and water your plant whenever the soil surface starts to feel dry.
These plants can be fed in the spring with slow-release pellets. You can feed the plant weekly during the growing season with a liquid 20-20-20 fertilizer at half-strength. Do not fertilize during the winter.
Temperature and Humidity
Cordyline thrives in temperatures above 62 degrees Fahrenheit and prefers a high humidity environment. Avoid putting the plant near a cold draft like a window, especially if the temperature drops lower than 62 degrees Fahrenheit. These are jungle plants, so if you're experiencing leaf drop, try raising both the temperature and humidity.
A mature, well-trimmed plant should have stems of various heights, up to 3 to 4 feet, and be clothed in leaves to the soil level. Over time, cordylines tend toward legginess so you will want to trim back individual stems in a staggered pattern.
Propagation is typically done with cuttings. Cut 3- to 5-inch pieces from mature stems and remove all of the leaves. Lay the pieces in sand and apply heat from below, as needed, to ensure a temperature of 62 degrees Fahrenheit. Shoots will grow from the eyes of the stems and can be planted in potting soil when they have about four to six leaves each. You can repot in spring or every other spring, as needed.
There are 15 species of Cordyline, but only a few are commonly seen in cultivation. C. australis, for example, resembles the yucca plant with narrow, long, and grayish to dark leaves; C. terminalis is a gaudy show plant with nearly infinite varieties. The thin leaves are wide (3 inches) and come in green, red, black, yellow, orange, and mixed colors. Varieties include "Tricolor," "Rededge," "Firebrand," and "Ti."
The naming of cordyline and related plants can get rather confusing because they are labeled with different names depending on where you are buying them. The most popular indoor cordyline is the C. terminalis, which is often sold as C. fruticosa or Dracaena terminalis.
Dracaena fragrans, with its bright green leaves, also are commonly sold as ti plants or Hawaiian ti trees. Cordyline and dracaena are both members of the agave family. The best way to tell the difference is to look at the roots: cordyline roots are white, while dracaena roots are yellow or orange.