Today there are around one thousand begonia species and many, many more hybrids being grown around the world. They originated in the main from Central and Southern America, China, India, Indonesia and South East Asia – none have been found in Europe or Australasia.
Here we have a brief description of each.
Tuberous Begonias: The ones we know today with the very large flowers are all hybrids originating from single flowered species found in 1860 in places like Bolivia and Peru. Their development over the past 120 years has resulted in the magnificent blooms they now produce. Large flowered tuberous begonias prefer to be grown in semi shade protected from strong winds. They do not tolerate frost and in early winter lose their foliage and remain dormant until spring.
Semperflorens Begonias: These will be known to most gardeners as simply bedding or wax begonias. They can be seen in many gardens and parks and make a wondrous site en masse. They come in a wide range of colours (except blue as is the case with all begonias) with either green, variegated or bronze foliage. They are more tolerant to the heat than their large flowered tuberous cousins – but, again, will not tolerate frost. They are in the main treated as annual plants but in warmer climates can be cut back in winter and will grow again.
Cane-like: These are so named because of their stiff cane like stems. They are also called "Angel Wing" begonias and sometimes tree begonias. They are excellent in both pots or open ground and can vary in size from a mere foot tall to in excess of 10 feet high. They have long clusters of small flowers which last for long periods in the warmer areas. They do not tolerate frost.
Rex Begonias: These, although rhizomatous in habit are classified separately. These plants are grown solely for their foliage which is truly magnificent. They are, however, not the easiest of begonias to grow, require a humidity of around 69% and are best grown in protected areas.
Hiemalis Begonias: These are often seen under different names such as Rieger or Blush begonias in garden centres and supermarkets. In New Zealand they tend to be grown as winter flowering plants. They are very susceptible to over watering but if well fed and grown in reasonable light they will smother themselves in one inch semi double flowers ranging from scarlet through to soft pastels, pinks and creams.
Trailing-Scandents: These often make good hanging baskets while others can be used as climbers in and around your garden. There is not a wide range of varieties in this group but they are well worth growing and propagate very easily from tip and stem cuttings.
Shrub-like Begonias: Like trailing Scandents these plants have excellent foliage which ranges from being extremely hairy to totally bare. In addition however they do flower really well if a good general fertiliser is regularly applied. As their name would suggest they tend to be bushy plants often with dense growth. Excellent as pot specimens.
Elatior Begonias: As previously mentioned the Hiemalis/Rieger begonias are regarded as winter flowering whereas the Elatior, although a similar begonia developed in recent years in Europe, flowers all year round and makes an excellent house plant.
Thick-stemmed begonias: A relatively small group not so widely known. As their name would suggest, they have thick stems from their base to their tips. They do make good pot plants, can grow to six feet in height and like plenty of good light.