Begonias bloom throughout the spring and summer growing season.The length of their bloom time makes them a desirable bedding plant. They are found in formal garden beds as well as in casual gardens where they are frequently used as border plants. Most begonias are annual flowers, meaning the entire plant lives for just one year. Some begonias are overwintered indoors, which expands their life and extends their blooming season.
Spring and summer
Begonia x argenteoguttata "Dragon Wings" is a long-blooming begonia species. Dragon Wings is a sterile plant and spends energy on flower production rather than seed production so it reblooms throughout the spring and summer but dies back after the first frost. Other begonias bloom from spring to summer but not as prolifically as Dragon Wings. All begonias bloom best when sited in garden areas that receive at least six hours of bright, indirect light every day.
Begonias planted in outdoor gardens die back with the occurrence of freezing temperatures. You can choose to replant a new crop in spring or you can take cuttings from your existing plants and propagate new ones in containers filled with perlite. Full plants, when dug up from the garden and trimmed back by no more than one-third of its existing foliage, overwinter safely in pots placed in indirectly sunlit locations.
Hardy begonias (B. evansiana syn. B. grandis) are capable of surviving in climates colder than the UK, where winters dip into temperatures -20 degrees C (-5 degrees F). Hardy begonias are not as prolifically flowering as other begonias but they are taller and provide a good background border for shady areas. Hardy begonias flower from early spring until the first frost.
Rex begonias are a begonia species planted and nurtured for their foliage, not their flowers. Tuberous begonias and wax begonias are noted for their compact size and colourful blooms but begonia blooms fade in heat and humidity. Cultivars from Begonia x tuberhybrida "Non-Stop" series are suitable for areas of the British Isles that are warmed by the Gulf Stream.