Cordyline Plants

The cordyline plant is a showy specimen, known for its tropical or dessert appearance and variety of bright colors, of foliage rather than flowers. Much like a palm, the long leaves have spiky tips. This evergreen can be used both indoors and out.
One of the best for a garden in colder climes is cordyline australis. Oddly, it is not from Australia but New Zealand, although the plant is widely grown in Australia and all over the world.
Other varieties of the cordyline plant can be grown indoors in any region, and are a widely known house plant, especially the cordyline fruitcosa or Ti plant.
The Cordyline australis includes the cabbage tree, red star, red sensation, New Zealand cabbage palm, and dracaena australis.  It is often sold under the name dracaena, but that plant is actually from Africa and thrives predominately in warm climates.
The stiff looking cordyline australis is similar in appearance to a Yucca tree.  The fronds may be bronzy red, bronze and pink combination, green with pink middle, and purplish red. Small fragrant flowers bloom in late spring.
Although it can be 30 feet tall and 12 feet wide at full maturity, it makes a  good outdoor container plant if it is kept in a smallish pot to control size, and repotted every year. It is recommended for zones 5, 8 to 11, 14-24, and sections of Hawaii [1]  Cordilyne australis can take temperatures to 15-20 degrees.
Care and Feeding
Give the plant full sun and light to moderate watering.
Feed 0-0-50 potassium sulfate.  This helps to enhance color and overall development
Pest problems and solutions:  Mealy bugs, snails, fungus gnats, mites, thrips and scales are the most frequent problems for the cordyline, and occasionally white flies.  They come from contaminated soil or from adjacent weeds or other growth in which they reside.  If possible, prevention is the best approach, making sure the soil is free of pests, and treating the adjacent areas, preferable with eco-friendly alternatives. Here are some suggestions for specific problems.

1. For snails, start with natural remedies such as a aluminum pie plates filled with beer—I believe they prefer Papist Blue Ribbon—placed around the plat, removing by hand, or use of a liquid snail killer squirted in a line around the periphery of the plant.
   
2. For scale - pest oil.  Apply the oil to a cloth and wipe foliage, especially lower leaves
   
3. For fungus- cut off affected area, spray with Yates rose gun
   
4. For mealy bugs living in the base of the plant, spray base with a safer less toxic product such as Ortho’s green alternatives, Bullseye or Orange Guard. Spray additional to soak into soil. Picking off bugs is another earth friendly and effective alternative.  Try digging into surrounding soil without upsetting the roots, then removing the bug-infested soil and replacing with new potting mix.

The cordyline plant varieties are numerous, the australis being an easy one to begin with.  You can experiment with outdoor containers that need warmer temperatures, moving them indoors in winter if your region gets a preponderance of days below 45 degrees.  There are cordyline plant enthusiasts online that can provide specific information about requirements for each variety of the plant.