Freesias belong to the same family as irises and crocuses and grow from corms. Corms are similar to bulbs but have a thin, papery skin covering them. They grow best in USDA zones 9 and 10, primarily in the southern and coastal regions of the country (see Resourses). You can grow them in colder climates, but you will need to replant them every spring. Dig up corms in the fall and refrigerate over the winter for spring planting. Freesias grow to be approximately 18 inches tall and come in two color varieties and with double blooms.
Plant freesia corms in the fall in southern climates and the spring in northern climates. Choose an area with well drained soil that receives full sun. Space each corm approximately 2 inches apart and plant 1 to 1.5 inches deep.
Keep soil moist once the plant begins showing leaves. Water regularly 1 or 2 times a week, not allowing the soil to dry out, until after the plant begins to die back in the fall.
Fertilize in the fall after the blooms begin to fade with a complete general-purpose flower fertilizer. Fertilizers formulated for irises work well with freesia.
Cover the corms with straw mulch before the first frost to help retain warmth. If your area receives constant hard frosts, dig up the corms or plant in pots that can be moved inside.
Remove plants infected by mites immediately. Plant freesia in a new location the following year. Removal is the only sure way to deal with these pests.