As long as you live in a completely frost-free region you can absolutely plant your Ti Plant as a landscape shrub. They add beautiful multi-colored foliage and dramatic growth all year long. When planted outdoors, make sure to plant in a location that is shaded from afternoon sun. Remember to keep the soil moist but not wet for extended periods of time, this can cause root rot.
If you want to plant your Cordyline Florica outside but don't live in a frost-free area, you can plant it in a well-drained container and leave it out from late spring to late summer. They make for fantastic patio plants in dramatic container gardens.