Begonias, although often sold as half-hardy annuals, are mostly perennials. The tuberous (and rhizomatous) varieties can be stored over-winter. Mature rhizomes produce bigger and stronger plants.
Fibrous rooted Begonias such as ‘wax’ and ‘Angel’ or ‘Dragon winged’ varieties can be pruned into a manageable shape and taken into the house. They will make for an attractive pot plant during the colder months.
Although many Begonias have tuberous roots, the majority of varieties are very tender and incapable of surviving the UK winter. They will require a period of dormancy in a cool, dry place. If you are considering keeping a rhizome in the same pot, then ensure you replace most of the compost in during early Spring. Failure to do so will result in poor growth and few flowers.
Protecting Begonia Tubers
Overwintering Begonia tubers is easy:
- Dig up the entire plant with foliage still attached before the hard frosts set in. Ensure that the tuber is not damaged in the process. Damage will often lead to rot and the death of your Begonia.
- With a sharp knife, cut away any disease parts of the tuber.
- Leave it to dry in a frost-free and sunny place for 1 week.
- Remove the foliage by gently teasing the stems from the tuber. Again, avoid damaging the tuber. Begonia rhizomes tend to be very delicate and easily scratched.
- Gently clean away excess soil or compost.
- I would recommend dusting your Begonia tuber with sulphur powder to guard against rot.
- Store tubers in a clean cardboard box. Space them evenly apart and place box in a dry, frost-free and dark cupboard until Spring.
I’d recommend that you occasionally check my Begonia tubers during winter. This will ensure they are still dry and rot-free. I tend to remove any that have gone bad to prevent the risk of infecting other tubers.
Replanting your Begonias
At all times throughout the following processes, ensure that your plants are protected from low temperatures and frost.
- Start planting during the month of April.
- Place tubers hollow-side-up in pots or trays of fresh general purpose compost.
- Cover with 1 cm (1/4 in) of compost.
- Place your plants in a shadier spot in a well ventilated room or frost-free conservatory. They will need plenty of light, but I’d recommend keeping them away from direct sunlight.
- Do not let the compost dry out. Spray or gently water. Ensure that the compost is well drained.
- As soon as flowering starts, feed your Begonias with a high potash feed. Tomato feed such as Tomorite it ideal.
- Remove dead flowers and foliage to encourage more growth and prevent rot.
- Don’t forget to enjoy your begonia plants.
As well as overwintering begonias, I also overwinter Dahlias. Please visit my guide to storing Dahlias over the colder months.