Overwintering Begonias

Although often sold as half-hardy annuals, most Begonias varieties are actually perennials. However, they are not at all frost hardy. The following article will give you advice on bedding begonias over-winter within the UK.

Tuberous rooted (and rhizomatous) varieties can be overwintered in a cool, dark and dry place. This is especially useful to the flower gardener, as mature rhizomes (or begonia corms) produce bigger and stronger Begonias plants. I like to leave mine in old hanging baskets in my garden shed. However, be prepared to lose a couple. Tuberous rooted begonias are prone to attack by Vine Weevil grub during the Summer. This will weaken, or even hollow out the tubers – the main cause of tuber death during the Winter.

Fibrous rooted Begonias such as ‘wax’ and ‘Angel’ or ‘Dragon winged’ varieties may be pruned into a manageable shape and taken into the house during Winter. They will also make for an attractive pot plant. Avoid draughty areas of the house to get the most out of your bedding begonias during the colder months of the year.

I prize my collection of tuberous-rooted varieties, such as Begonia ‘Apricot Shades‘, ‘Non-stop Mocca‘, ‘Aromantics’ and trailing classics such as ‘Cascading Picotee’ and Boliviensis.

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 prefer to overwinter your potted begonias by keeping the rhizome (or corm) 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. They will also need feeding when they start to produce leaves.

Protecting Begonia Tubers

Overwintering Begonias is easy:

  1. 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. Shake out any Weevil grubs
  2. With a sharp knife, cut away any diseased parts of the tuber
  3. Leave it to dry in a frost-free and sunny place for 1 week
  4. 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
  5. Gently clean away excess soil or compost with your finger tips
  6. I would recommend dusting your Begonia tuber with sulphur powder to guard against rot
  7. Store tubers in a clean cardboard box. Space them evenly apart and place the box in a dry, frost-free and dark cupboard until Spring

I’d recommend that you occasionally check your overwintering Begonias. This will ensure that they are still dry and rot-free. I prefer to remove any tubers that have gone bad to prevent the risk of infecting other tubers. If in doubt, keep them. Sometimes, Begonia tubers look totally dead, but re-sprout in Spring.

Note: If you live is a very mild part of the UK, you might want to try leavings your Begonia tubers in the ground overwinter. Cover them will straw or leaves until the risk of frost has passed. I have a number of tuberous Begonias in my garden in Dawlish, Devon. They seem to thrive, even when left in the ground during Winter. This can be risky. I am sure a harsh Winter will eventually come and finish them. But they have been in the ground now for the past 6 years!

Begonias: when to plant

At all times throughout the following processes, ensure that your plants are protected from very low temperatures and frost.

  1. Bring your begonias out from overwintering during the month of April
  2. Place tubers hollow-side-up individually in pots or in rows in trays of fresh general purpose compost
  3. Cover with 1 cm (1/4 in) of compost
  4. Place your plants in a shadier spot in a well-ventilated room, frost-free conservatory or greenhouse. They will need plenty of light, but I’d recommend keeping them away from direct sunlight. I place mine on a lower tray under the bench in my greenhouse. They get plenty of morning sun, but very little during mid-day
  5. Do not let the compost dry out. Spray or gently water. Ensure that the compost is well drained
  6. As soon as flowering starts, feed your Begonias with a high potash feed. Tomato feed such as Tomorite it ideal
  7. Remove dead flowers and foliage to encourage more growth and prevent rot and disease
  8. Don’t forget to enjoy your begonia plants! They are very versatile and most varieties can cope with some level of shade

Begonia tubers: Dividing

  • Plant the begonia tubers during March or April. For best results, grow at a temperature of about 18°C (64°F)
  • Fill a tray or large pot with 3 – 4 inches of moist and gritty (or sandy), free draining potting compost
  • Place each tuber on to the surface of the compost. Ensure that the depressed side is facing up. Space them at half inch intervals at a depth of 1 inch
  • Once growth begins, divide each tuber with a sharp, sterilised knife. Ensure that each section has at least a single bud on it and root below it. Dividing each tuber into quarters is ideal
  • Allow each sliced begonia tuber to heal for a couple of hours
  • Place each segment into individual pots of firm compost. A good quality, multi-purpose compost will suffice. Ensure that the tops of the tubers are level with the top of the compost
  • Keep the compost moist, but do not over water

As well as overwintering begonias, I also overwinter Dahlias. Please visit my guide to storing Dahlias over the colder months.

James Middleton

An obsessive gardener since 1982. Day-time job - web designer and developer and University lecturer.

This Post Has 9 Comments

  1. Barbara Fortin

    I am new at this gardening thing thing. I was told I can ‘tent’ my bagonia to save it over the winter. Is it that simple. I live in Bellingham Washington. It is still before the frost.
    Barbs

  2. James Middleton

    Hi Barbara,

    I haven’t heard of ‘tenting’ begonias, except perhaps for propagation purposes. I’m not too sure what kind of weather you have in Bellingham – how cold it gets or general humidity, but I would suggest that digging up and over wintering your begonias is a very safe option. It also gives you the opportunity to perform a little health check on your plant’s tubers. I found a few grubs in mine this year – now I’m glad I checked.

    If your begonias are fibrous rooted, then you can either dig them up, trim them back and store as house plants over winter, or take cuttings and keep in a warm spot in your house. Most begonia varieties easily take from cuttings – hardly any labour at all.

    I hope this helps.

  3. diane turner

    i’m new at geraniums and begonia over wintering. i have kept plants as indoor but have many pots and not enough room for all so have decided to dryroot them. i am zone 6 (ontrio canada) have done much research and have come to the conclusion that dry root is the best method ?? i have both geraniums and begonias. any advice would be welcome.

  4. James Middleton

    Hi Diane. The method doesn’t really matter, as long as you do the following to over winter your begonia tubers:

    * Keep in a frost free place.
    * Keep dry.
    * Check on them every now and then to ensure aginst fungal infections or pest infestations.
    * You can pack them in dry compost or in newspaper.

    Let the frost just touch the begonia plants before removing the tubers – this will allow for some of the nutrients to return back to the tuber. Don’t leave them in the ground for too long or you will loose them! It’s also a very good idea to label each tuber. I forgot to do this one year and had trailing begonias in tubs and erect forms in my hanging baskets!!!

  5. James Middleton

    Last year, I left my tubers on my windowsil to dry for a week. Once dry, I tapped away the remaining compost and found and removed several vine weevil lavae. I’m glad I did this now as the weevils would have had a begonia snack over winter!

    Always be careful when cleaning a begonia tuber. They may look as tough as old boots, but they are not. The skins around the tubers are very thin and can easily peel away increasing the chances of fungal infection.

  6. CAROL IRELAND

    My husband has stored my begonia tubers in newspaper, in an airtight polystyrene box.
    Is this OK.

  7. James Middleton

    I think that sounds like a reasonable why to store them. Just make sure you check them every couple of months to ensure that they aren’t going rotten and keep each one separately wrapped. Thanks – a good suggestion.

  8. john hitchener. macclesfield cheshire

    Hi James last year I left my tubers in the tubs in which they had spent the summer months. Letting the compost dry out and storing in a frost free greenhouse.

    This spring they came back to life giving me a flying start and enabling me to take fresh cuttings for rooting I then replanted the original tubers/plants into fresh tubs and compost

    I may have been lucky but I will try again this year to see if it works again, of course correct labelling is important at the time of storing

  9. James Middleton

    To be honest with you, I think that this is the safest approach – keeping them in the tub or container they originally grew in. Be careful though – a sharp frost could still do major damage. A cool greenhouse or shed should be a safe environment for most winters. I would also recommend avoid watering. Don’t let them totally dry out, but a light misting over the compost if it dries out should do the trick.

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