As autumn deepens and the threat of frost looms, gardeners on Canada's West Coast are faced with a seasonal task: preserving their delicate hanging begonias for next year's bloom. Published on December 2, 2025, gardening columnist Helen Chesnat provides a timely and detailed guide for successfully overwintering these popular plants.
The Coastal Advantage and the Approaching Cold
Chesnat notes that the mild November typical of coastal British Columbia often allows begonia baskets to remain lush with foliage and flowers well into autumn. However, as temperatures inevitably drop, action is required to protect the plants' vital tubers. The key is to act before the first frost arrives, which can be imminent even in relatively temperate zones.
Step-by-Step Process for Winter Storage
The initial step is to relocate the hanging baskets to a sheltered spot, such as against a house wall under a broad overhang. Chesnat advises against forcibly removing the remaining stems, as this can damage the tuber's growth ring. Instead, she recommends giving stems a gentle nudge; at this stage, they often fall away easily without causing harm.
There are two primary methods for storing the tubers through the winter:
Option 1: Storing the Entire Basket
If space permits, the entire basket can be placed in a frost-free storage area with ideal temperatures between 4°C and 10°C.
Option 2: Storing the Tubers (More Common)
For most gardeners, unearthing the tubers is the most space-efficient method. Chesnat outlines her proven technique:
- Carefully remove the tubers from the soil, brushing off excess planting mix.
- Keep labels with the tubers for easy identification in spring.
- Place them in a single layer in shallow boxes.
- Cover them lightly with vermiculite or peat, with Chesnat preferring vermiculite for its effectiveness.
Winter Monitoring and Spring Revival
Successful overwintering requires occasional check-ins. Gardeners should inspect the tubers a few times during the storage period. Shrivelling is a sign that the storage medium needs a light misting or that the storage temperature is too warm. Conversely, it's crucial to avoid over-dampening the medium, which can lead to mould.
The signal to restart growth comes from the tubers themselves. When pink nubs appear on the tuber tops, it's time to begin the revival process indoors. Chesnat aims for this step around early March, giving the plants a head start before moving them back outside after the last frost.
By following this expert guidance, gardeners in Vancouver and across coastal BC can ensure their begonias survive the winter and return for another spectacular season of colour.
