Freesias are tender bulbs native to South Africa. They will not survive winter outdoors in areas colder than USDA Zone 9. In these areas, they should be forced in pots indoors and then discarded. In areas warmer than Zone 9, they can be planted outdoors. They will bloom in these areas in early spring and come back year after year.
In Zones 9 and warmer, plant freesias in a garden bed that is in full sun that gets at least eight hours of sun per day. In cooler zones, they must be grown in pots because they will not survive winter's freezing temperatures. Improve the soil by adding a trowel full of compost to the planting hole when setting out freesia bulbs.
In Zones 9 and warmer, plant freesia in early fall. Plant them two to three inches deep and three to six inches apart. In zones cooler than Zone 9, plant them in late fall in six-inch or larger pots filled with indoor potting soil. Bury them at least four inches below the surface of the soil in the pot. Always plant freesia with their pointed end up.
Water well. Cover freesia planted outdoors with a two-inch layer of fallen leaves to protect them from unseasonable cold temperatures. Put potted freesia bulbs in an unheated closet or basement at temperatures between 45 and 60 degrees Fahrenheit. Temperatures warmer than 60 degrees will cause the plants to grow weak and spindly.
Indoor- or outdoor-grown freesia will develop roots over the winter months. Water only when dry; do not over-water.
Leaves and flower stems will appear in late winter. Indoors, bring into bright light when you notice leaves and stems breaking the surface of the soil. Keep growing at cool temperatures below 65 degrees Fahrenheit. Outdoors, they will produce flowers in early spring.
Outdoors, leave the foliage to die down naturally and produce food for next year's blooms. For freesia grown in pots, the bulbs will be exhausted from the forcing process and should be discarded. It is not possible to carry them over and force again the following year.
Outdoors, cut the foliage off after it turns yellow and dies. The bulbs will remain dormant for a few months and begin growth again in late winter.