Native to South Africa, freesias naturally bloom in spring. Growing freesias and the precise timing of their flowers differs depending on your climate. Freesias grow from bulblike corms and overwinter outdoors in the ground in all of the British Isles.
Freesias grow best outdoor in the garden where summers are hot and dry. That makes the plants go dormant. Cooler weather from autumn to spring with ample rain in the winter yields flowers in spring.
In regions with winters colder than -6.66 degrees Celsius (20 degrees Fahrenheit), gardeners plant the corms in spring once danger of frost passes. The corms produce leaves and then yield flowers roughly 10 to 12 weeks after planting. In wet summer climates, dig up the corms once leaves yellow and replanted them in autumn.
Freesia corms produce their flowers after exposure to cool nighttime temperatures. Where hardy outdoors, flowering naturally occurs in spring. If grown in containers or planted outdoors every spring, corms are either prechilled at -1.11 to 4.44 degrees Celsius (30 to 40 degrees Fahrenheit) or the plants are exposed to cool nights as the foliage grows heading into early summer.