How to grow Begonias

Begonia 'Glory Bicolour' from Thompson & Morgan

Begonias are garden favourites for their flamboyant and colourful summer blooms
Image: Thompson & Morgan

You'll be astonished at how many species of Begonia are available. From leafy house plants to bright summer bedding - there are so many to try!

Most commonly seen are the tender perennials, Begonia sempervirens and Begonia x tuberhybrida, which light up gardens with their flamboyant display. These hard working plants add a rush of colour to the garden in summer, which often lasts right through to late autumn.

Which Begonias can be grown in the garden?

Begonia 'Santa Barbara' from Thompson & Morgan

Begonia 'Santa Barbara' creates a harmonious display with its cool, white blooms pink stems.
Image: Thompson & Morgan

Fibrous rooted Begonia sempervirens are generally treated as annuals for filling beds and borders, or planting in window boxes and patio pots. Their fleshy leaves and neat, upright habit make them useful for creating a neat, uniform bedding display that will bring colour all summer long. At the end of the summer they can be discarded, and fresh plants bought in the following year. Look out for the dark, bronze-leaved varieties which create a striking contrast with their green-leaved cousins.

The tuberous Begonia x tuberhybrida types are showier, with large blooms that make an impressive display. Some are upright and bushy, while others have gently trailing stems. Perfect for patio pots, window boxes and hanging baskets! These garden show-offs will really bring the 'wow' factor, flowering endlessly from summer right through to the first frosts in late autumn.

Where to grow Begonias?

Begonia 'Mega Watt' from Thompson & Morgan

Begonia 'Mega-Watt' is ideal for beds, borders or containers
Image: Thompson & Morgan

Begonias are extremely adaptable, thriving in sun or shade! This makes them useful for drop-dead gorgeous, summer displays in even the shadiest spot of the garden. In fact, the tuberhybrida types actually prefer a little less sun, as they tend to fade faster in very hot locations. They also have more delicate stems, which can snap in strong winds, so try to offer a sheltered site wherever possible.

Beds and borders:

Grow Begonia sempervirens in beds and borders to create a carpet of colour, or dotted in among mixed patio pots. They even work well in a window box for a low growing, compact display.

Varieties to try:

Containers, hanging baskets and window boxes:

For a cascading display from baskets and window boxes, opt for a trailing Begonia x tuberhybrida cultivar. The upright, bushy forms are better suited to a patio pot of their own where they can really show off.

Varieties to try:

How to grow Begonias from plug plants

Begonia semperflorens 'Lotto Mixed' from Thompson & Morgan

Begonia plug plants can be planted directly into flower pouches for a vertical display that will last the summer.
Image: Begonia semperflorens 'Lotto Mixed' Thompson & Morgan

Begonia plug plants can be planted directly into flower pouches, but are best grown on if they are to be used in baskets, containers or for bedding schemes.

Pot up plugs into 7.5cm (3") diameter pots using a good quality, free-draining compost. Grow plug plants on in bright, frost free conditions such as a heated greenhouse, bright windowsill or conservatory. Transplant Begonias into their final containers when they have increased in size.

How to grow Begonia tubers

Begonia tubers are ideal for containers and baskets, making a larger plant in the first year than plug plants or growing from seed.

  • From February onwards, start Begonia tubers off in pots of well-drained, moist compost. Simply press the tuber onto the surface of the compost to a maximum depth of 2cm, with the indented side facing upwards.
  • Grow them on in a warm, frost-free position in bright light.
  • Transplant Begonias into their final containers when they have increased in size.

Take a look at our video to see how easy it is to plant begonia tubers.

How to sow Begonia seed

Growing Begonias from seed is the most cost effective method, but does require more patience. It's worth noting that Begonia seed is extremely fine, so take care when opening the packet.

Sowing time: Mid-January to mid-March.

  • Sow seeds on the surface of lightly firmed, moist seed compost in pots or trays. Avoid covering the seed or excluding light as this helps germination.
  • Place in a propagator or warm location, at a temperature of around 24-27C (75-80F). Keep the surface of the compost moist but not waterlogged.
  • Germination will usually take 15-60 days.
  • When large enough to handle, transplant the seedlings into 7.5cm (3") pots and continue to grow them on in bright, frost-free conditions.
  • Transplant Begonias into their final containers when they have increased in size.

Caring for your Begonias

Begonia 'Illumination Mix' from Thompson & Morgan

Once they are in full growth, your hanging baskets will need watering every day
Image: Begonia x tuberhybrida 'Illumination Mixed' from Thompson & Morgan

When begonia plants are well grown and all risk of frost has passed, gradually acclimatise them to outdoor conditions over a period of 7 to 10 days, before planting them in their final positions. Choose a sunny or semi shaded position that is protected from strong winds.

You'll need to water your Begonias regularly. By the height of summer it is likely that hanging baskets will need a good soak every day! Containers and window boxes will also need checking daily. You can set up an automatic watering system to help with this task.

Feeding is just as important if you want your plants to reach their full potential. You can either add some slow release fertiliser to the compost when you transplant them to their final positions, or use a liquid fertiliser once a week throughout summer until the end of August.

Storing Begonias over winter

Begonia tubers closeup

Dry begonia tubers in a well ventilated, frost free location before storing them for the winter
Image: Shutterstock

As the summer draws to an end, you may be wondering how to save your tuberous Begonias for another year. It's surprisingly simple!

Stop feeding your plants by the end of August and reduce watering. When the earliest frosts blacken the foliage it's time to cut back the stems and remove the tubers from the soil.

Let them dry off in a frost free and well ventilated location - a shed or greenhouse will do nicely. You can brush any remaining soil off of the tubers and trim away any last remnants of the stems. After a week they should be completely dry and can be stored in trays of loose, dry peat or sand. Alternatively you can wrap them loosely in newspaper or paper bags. Store them in a cool, dry and frost free place over winter.

Be sure to check them regularly any remove any which are damaged or show signs of rotting - these should be discarded. When spring comes around, you can pot them up and they will begin to grow again.

Now you've learned how easy it is to grow Begonias, why not fill your garden with colour from these dependable, summer-flowering beauties! For more information on growing and caring for your begonias, visit our begonias hub page, which links to a series of online resources.

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