Tuberous Begonias are tender perennials so will return year-after-year as long as they are protected from frost. They can be grown in borders or pots and will flower from June to October. Buying tubers can be a cost effective way to enjoy begonias all summer long. They are best started off indoors from as early as January or February and will take approx 6-8 weeks to sprout. Once the threat of frost has padded you can move outdoors.