Growing Begonias
In botanical writing, they are properly described as Begonia tuber hybrida and are the result of a hundred crosses with multiple ancestors.
But in our gardens, we simply call them gorgeous.
We divide them into several different classes:
B. bertinii (with a hanging down or pendulous flower, usually large and single)
B. crispa (with a single flower)
B. double (you figure this one out – hint: it has a double flower)
B. pendula (hanging or pendulous flower but tends to doubles)
B. fimbriata (with ruffled and double flowers)
B. marmorata (double flowering)
B. multiflora maxima (small flowering)
How To Use
All share large, dark-green leaves and make excellent indoor plants.
Mostly though we know them from those gorgeous hanging baskets and garden displays that are stunning in their color show.
This plant comes in a range of colors from reds, through pinks, yellows to whites. There are a few purples and apricots as well as bicolors in the color palette as well.
Begonias make excellent cut flowers and a double flower floating in a rose bowl makes an excellent table ornament, lasting for over a week.
How To Grow
If you get these plants started at a nursery, they will flower all summer with basic care.
This means a light shade with no direct sunlight. Full sunlight “burns” the leaves causing a browning and cracking of leaves and flowers. So in practical terms, you can put them in the weak morning sun but not the hot afternoon sun.
They must be protected from approximately 10am onwards through to 4pm when the sun cools down again.
Planting
The average size of begonias is 8 to 14 inches (25-40 cm) and when planting in the pot or ground, the recommended distance is 5 to 6 inches apart.
Deep planting will kill this shallow rooted plant. Set the tuber just below the soil level and barely cover it to protect it from the light. Do not plant is deeply or it will rot.
Hardiness
This is not a hardy plant. If you frost it, it will respond by dying.
Although I note that if the tops get accidentally frosted, cutting the tops off immediately and bringing the tubers indoors will often save the tuber. If the tops are allowed to rot down to the soil, the tubers will go as well. The key is fast action after a frost.
Storing Tubers
Once the growing season is over, dig up the tubers and store them dry, layered in peat moss or dry vermiculite in a cool, dry spot.
Starting Tubers
You can (and should consider) starting your tubers 4 to 6 weeks before planting them outdoors.
The biggest tip I can give you here is to give them full sunlight in your growing area and use only warm water to irrigate.
At this early stage, begonias will rot off quite quickly if they are grown cool or shocked with cold water.
A night temperature of 65F minimum is recommended and 72F is far better.
Don’t forget the warm water!
Huge Flowers But Politically Incorrect
If you want to grow the flowers of double tuberous begonias that are of show exhibition quality, then you have to understand a little botany.
If you look at your developing flower, you’ll note it is composed of two separate flowers on the same stem.
The big, double, gorgeous flower that you lust after is the male. The smaller, single, insignificant flower behind the male is the female.
If you want the large double flower to grow quite large, the female flower must be pinched off as soon as possible. Only without the energy taken by the female can the male grow into a massive specimen.
A footnote to this is that this big double brute is sterile and doesn’t produce any pollen. You can make of that little begonias fact what you will. :-)
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