How To Grow Tuberous Begonias

 

How to Grow Tuberous Begonias Transcript

Hi, I’m Barb Pierson, the nursery manager at White Flower Farm. I’m here in our Begonia house with Cheryl Karpeichik, our head gardener. She is responsible for growing all our Begonias for our beautiful Tuberous Begonia display. We get our Begonias from Blackmore and Langdon in England and Cheryl grows them on for our display.

We recommend planting your tuber in early to mid March. Remove the tuber from its bag and discard any packing material. You’ll notice the top of the tuber is slightly concave and may have buds showing. This is the new growth so handle your tuber gently to avoid knocking your buds off. Select a small pot just a little bit bigger than the tuber itself. Fill the pot about two-thirds full with well-drained, soilless potting mix.  Carefully place the tuber rightside up on the potting mix. Cover with mix to the top of the pot and firm it lightly. Water the pot thoroughly and keep it in a warm place indoors that remains over 60 degrees and provides bright, but indirect light. After about 3 weeks you’ll see the soil surface starts to crack. It’s almost like a tiny earthquake, and that’s an exciting sign. It means your Begonia is about to emerge. After a few days this starts to happen. You’ll see the tiny stems and leaves start to poke through the surface.

Once your Begonia has filled its pot with roots it’s time to move it into a larger pot. A 7–10" pot is the size we use. Fill the pot with enough potting soil so the top of the root ball will be about 1" below the rim of the pot. Carefully remove the root ball from the original pot and place it in the larger container. Fill in around the roots with more soil. We add a time-release fertilizer at this point which you can purchase at your local garden center. Continue adding potting soil and firm it around the plant’s roots. Water thoroughly.

When the threat of frost has passed, set the pot outside in a bright, but not sunny location, where the air circulates freely. Tuberous Begonias do not grow well in deep shade and are susceptible to powdery mildew in humid conditions. When your Tuberous Begonia is 4–6" tall you’ll want to add a stake to support the stems. During the summer remove spent flowers to keep your plant looking tidy. For more information on growing tuberous begonias please see our cultural instructions or visit our website whiteflowerfarm.com.

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