I bought some begonias last fall and have been growing them since. I got one hanging basket begonia and one upright plant with huge blooms. Neither one have flowered yet and I am on a mission to figure out why!
Begonias don’t like full sun! They actually prefer to have about 50% shade and need morning/ AM sun. Their leaves can become sunburned easily so be careful where you plant these guys!
Begonias are another plant that can be killed by over watering them. Begonias need water but cannot become waterlogged! They should only be watered when the top soil is dry, be very careful to avoid over watering these!
Begonias should be planted in the spring and many sites say that your begonia tuber should not be planted until a sprout appears first. Tubers sprout best in a warm and dark place so if yours is slow to sprout check it’s location.
The autumn and fall cooler temperatures will not damage your begonia if you have them outside. Also, Begonias can be beautifully grown indoors if you prefer this method. They will do best in filtered light through a sheer curtain or something similar.
It is recommended that you stop watering your begonia tuber in or around may. This is the beginning of their dormant time and they will need this time for the tuber to grow and store food for the next bloom season. Wait to dig up your begonias, the foliage must dry up and break away “with the brush of a hand” before you should dig them up.
For prorogation techniques check out this helpful site: http://www.bradsbegoniaworld.com/prop.htm
If your begonia grows flower buds but they fall off before opening this is a sign that your begonia is over watered. If your begonia had large leaves and is becoming tall and “spindly” it is not getting enough sunlight and needs a brighter location.
I did not take the photo listed in this post. I also do not hotlink images so I am giving credit where credit is due. The image is from: http://www.bookishgardener.com/plants/index.html