Begonia Boliviensis

View of south patio with pots of Begonia boliviensis 'Bonfire' surrounding Ensete ventricosa 'Maurellii'

Closeup of pots of Begonia boliviensis 'Bonfire'

     There are a number of begonias, which we normally think of as non hardy plants here, which are indeed  hardy for us.  One of these is Begonia boliviensis, a tuberous begonia which hails from high elevations in the Andes of Bolivia and Argentina.  Plant Delights Nursery lists this as hardy to zone 7b which is a colder climate than ours.  However, although I have grown various plants of Begonia boliviensis for probably 10 years, I have never tried this one in the ground so I cannot say from personal experience that it is hardy here.   These are not expensive plants and they are easily found at local nurseries so perhaps I will try them in the ground one of these days.
     The plants you see in the pictures are ones I bought last year in 4 inch pots at Bainbridge Gardens and they were labeled as Begonia 'Bonfire'.  This is a form of Begonia boliviensis, although I do not know if it differs from the straight species which I have grown in the past.  It does not look much different from the straight species to my eye.  Sometimes growers slap fancy names on straight species of plants in a marketing attempt.  I have seen another variant of Begonia boliviensis in nurseries this year which did appear to be slightly different in that the leaves were darker.  I need to buy some of those!
     Begonia boliviensis is a tuberous begonia, and, in fact, it is one of the ancestors of the fancy tubrous begonias that you see in nurseries and hanging pots.  Over time, it will form a very large tuber indeed.  I have had tubers over a foot in diameter formed over time on this plant. 
     The reason I haven't grown this plant in the ground is that I think it makes a great pot plant because of the way the flowers will hang out over the edge of the pot.  I think that it would just be lost out in the jungle of the garden if it were in the ground, whereas in a pot it shines.  Also, it appreciates good living in the summer--i.e., it likes being adequately watered and fertilized, and I can do that better when it is in a pot. 
     These begonias are quite easy to winter over.  I just take the pot into my sunroom and forget about them until the spring when I bring them out and start watering and fertilizing them again.  In the winter when they are inside they can be left to go dormant.  They need no water or light and all the foliage will die away.  I have been told that they will go dormant no matter what you do in the winter, but I have never tried to keep them from going dormant, so I cannot attest to this based on personal experience.
     These begonias are easy from seed and a lot of seed is continually set all summer long.  It is tiny seed, almost like light brown dust and it should be sowed on the surface of the pot and kept constantly moist.  Germination should be fast and if you do this you will have more plants than you know what to do with.  Cuttings can also be taken, but they must be done early enough in the year to form a tuber before winter or else, I have been told, they will not return after going into dormancy.
     I would highly recommend growing these begonias because over time they make impressive plants in pots, they are easy care, and the hummingbirds love them.