It’s Showtime! The Next Stage in the Life of Tuberous Begonias

By Cheryl Whalen, Head Gardener

So here we are already midway through July. I know I’ve left you hanging for a bit and I can tell you are hankering for more tales of the tuberous begonias. With the bulk of the garden planting done and our annual Open House in the rear-view mirror, my attention can now turn back to making the begonias happy and comfortable.

The begonias responded nicely after making their move into their final pots. They got to work rooting into their new-found foot room and in turn they increased their lush top growth in height and girth. Then the buds began to appear and the first satiny flowers of the season unfolded.  We were ready for entertaining! I was able to open the doors of the display house to our visitors a week before the first of June which is my usual targeted opening day.  The first few flowers of the season seem extra special to me. Maybe it’s because I haven’t seen them in months and I’ve missed them so.

The first blossom of the season for Begonia 'Saturn.'
The first blossom of the season for Begonia ‘Saturn.’

The first flowers are just the beginning. That one boutonniere of a blossom is the precursor to the formation of many buds and soon the plants can become heavily clad in bodacious blooms. The next task that becomes urgent as the upright begonias grow taller is staking. Even though the plant stems appear thick and strong, it is very necessary to provide some additional support for those stems so that the weight of the blooms and gravity don’t cause the stems to topple and snap away from the tuber. I provide each plant with a sturdy stake or sometimes two. I push each stake into the soil being very careful not to impale any of the precious tubers. Then patiently I go through each plant, tying in each main stem to the stake using my soft, 3-ply garden twine. I like to loop the twine around the plant stem first and then cross it over and loop around the stake making a figure eight with the twine. The stem still has room to grow without being girdled by the twine and the knot seems to stay put where it’s tied around the stake.

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Even though the Begonia stems appear thick and strong, it is necessary to provide additional support for those stems so that the weight of the blooms and gravity don’t cause the stems to topple and snap away from the tuber.

As summer progresses I settle in to my daily routine of begonia upkeep. I check each plant daily for water needs, allowing the soil of each to become dry between watering. I don’t allow the plants to be dry for too long especially on hot, sunny days when the possibility of wilting looms. I give the plants the daily once-over removing any spent blossoms and the occasional unsightly leaves that may appear.  At the same time, I double-check the plants for adequate staking. As the plants continue to grow, I sometimes have to add more ties or stakes to ensure my plants continue to stand tall.

Aside from the bit of time it takes to do the daily chores, the rest of the summer can be spent enjoying the fantastic flowers! I thought I’d introduce you to some of the family . . .

B&L Tuberous Begonia 'Firedance' in hanging basket.
Blackmore & Langdon Tuberous Begonia ‘Firedance’ in a hanging basket.
Blackmore & Langdon Tuberous Begonia 'Nectar.'
Blackmore & Langdon Tuberous Begonia ‘Nectar.’
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White Flower Farm’s Begonia House at the height of the blossom season.
john smith, center, a fragrant variety with fruity spicy scent
Begonia ‘John Smith,’ center, a fragrant variety with a fruity spicy scent.

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