I bought several pots of dragon begonia last year and more or less successfully over wintered them until we got that blast of cool weather this spring which set them back. Once outside in summer, the straggling stems eventually took off and at this time in early fall, I have one very healthy full pot of begonias which I hope to over winter again.
Is there anything else I can do besides placing them in a sunny location and underwatering in the winter season that will help them survive till spring?
Thank you for contacting the Toronto Master Gardeners with your concern about overwintering your Dragon Wing Begonia, Begonia x hybrida ‘Dragon Wings’. You certainly have a healthy, beautiful plant and I can understand why you would like to keep it until next spring when it can be placed outside again. Dragon Wings are so popular because the plant continues to flower consistently throughout the year. This is because it is sterile and therefore keeps flowering in an attempt to reproduce.
There are a few things you may want to do to help your begonia overwinter indoors more successfully. Placing it in bright sunlight as you did last year is a good first step. You will want to make sure the plant has good air circulation and is not close to a heating vent. Placing the pot on a pebble tray with water will be beneficial by raising the humidity level around the leaves instead of misting the leaves which may encourage powdery mildew. Begonias do not like to dry out so keep the soil moist, not soggy. Add a light fertilizer once a month at half strength to the moist soil. If your plant gets leggy, you can cut the plant back to encourage new growth.
To cover all the bases and make sure you have at least one healthy plant in the spring, take 10 or so 8 – 10cm cuttings from non-flowering stems and root them in moist, sterile potting soil. They should develop roots with 4 weeks.