How to grow begonias
All you need to know about growing colourful begonias in the garden.
Begonias are flamboyant, mostly tender perennials that are used in bedding, pot and hanging basket displays. They have a reputation for being a little old fashioned, but the bold new varieties are very different to the dainty plants that were traditionally used in bedding schemes. Some have masses of long-lasting, showy flowers in neon shades that are great for pots and hanging baskets, while others are grown for their spectacular, eye-catching foliage. All begonias do best out of direct sun, so are a welcome addition to a shady patio or border.
Begonias can be categorised as follows:
- Tuberous begonias are grown from round, fleshy tubers. They have big, showy flowers in bright shades of pink, yellow, orange, red and white, throughout summer and into autumn. They make excellent pot and hanging basket plants, as some of them trail. As they won't survive in cold weather, the tubers are often planted as annuals each year, or dug up and stored indoors for the winter.
- Fibrous-rooted begonias, as their name suggests, have a typical root ball of thin, fibrous roots. They include the dwarf bedding types, known as wax begonias (Begonia semperflorens) and tend to have smaller leaves and flowers. They can be grown in containers and window boxes or as bedding at the front of a shady border. They are usually treated as annuals and discarded at the end of the season.
- Hardy begonias can be left in the ground in winter in sheltered, warm locations. The most common type found in the UK is Begonia grandis subsp. evansiana.
- Foliage begonias are grown for their spectacular leaves, which come in a range of shapes, colours and patterns. They include the cane types (with upright stems that have different segments, like a bamboo cane, also known as angel wing begonias thanks to their beautiful leaves). They are popular as house plants but are increasingly grown outside in summer, where they will bring a jungly, exotic look to a patio or shady border. The Rex begonia (Begonia rex) has the showiest leaves of all, while Begonia luxurians, the palm-leaf begonia, looks like a palm tree and can reach 3m tall.
How to grow begonias
Grow begonias in peat-free, multi-purpose compost in dappled sunshine to partial shade. Plant tubers of tuberous begonias in spring. Only plant begonias outside in May, when no more frosts are forecast. Water regularly and feed weekly with a high potash fertiliser like tomato feed. In autumn, dig up tuberous begonias and store the tubers in a cool, frost-free spot for winter. Bring fibrous-rooted types indoors over winter, or treat as annuals and throw on the compost heap. Foliage begonias are grown as house plants but can enjoy time outdoors in summer.
More on growing begonias:
Begonias: jump links
- Where to grow begonias
- How to care for begonias
- How to propagate begonias
- Begonia problem-solving
- Begonia buying advice
- Types of begonia to grow
Where to plant begonias
Begonias grow well in dappled or partial shade – avoid south-facing spots as the foliage can burn in direct sunlight. If you're growing begonias in a greenhouse, shading may be required.
Tuberous begonias are ideal for growing in pots and hanging baskets. They have fairly brittle stems and heavy flowers, so grow them in a sheltered spot. Flowers will go over very quickly if they’re too hot. Fibrous rooted begonias can be packed quite tightly into mixed summer displays of other bedding plants.
Foliage begonias are best grown as house plants, in dappled shade. They will enjoy a holiday in the garden in summer, in dappled shade.
How to plant begonias
In March or April, you can buy begonia tubers at the garden centre or online. Plant the tubers into individual pots or into a seed tray, hollow side up. Plant 2.5cm deep and keep in a warm spot that is at least 18°C. Once the leaves begin to show, pot on into larger pots filled with John Innes No. 2 compost or peat-free, multi-purpose compost.
Harden off the plants before planting them out in the garden in May, when no further frosts are forecast. You can also buy tuberous begonias as fully grown plants, although this is a more expensive option.
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Other begonia types can be bought as pot-grown plants or plugs. Grow them in a greenhouse or sunny windowsill and harden off after all risk of frost has passed before planting outdoors.
How to care for begonias
Keep plants well watered but allow the soil to dry out between waterings – this is especially important for tuberous begonias, which can rot in waterlogged soil.
Feed tuberous begonias weekly with tomato feed in summer, especially pot-grown plants. Alternatively, add a slow-release fertiliser pellet to the compost when planting. Never feed tuberous begonias into September as plants should be encouraged to slow down for the year. From October, reduce watering and remove flowers so the plants to put energy back into the tuber. Once the foliage has been blackened by frost, life the plants. Remove the compost from each tuber, cut the stem back to about 6cm and store in a dark, cool, frost-free place until March, when it can be brought back into growth again.
Fibrous-rooted begonias tend to be grown as annuals. Feed weekly in summer and dig them up and compost them when they've finished flowering.
The small, insignificant flowers on foliage begonias are often removed so as not to detract from the beautiful patterned foliage. You can put plants outside in summer, but bring them indoors as the weather cools.
How to propagate begonias
Tuberous begonias don’t come true from seed, so propagation by cuttings is recommended. In March or April pull new shoots that form on the tubers away with your fingers. Pot them up into individual pots and put them in a heated propagator. Place the propagator in a shaded spot and expect to see signs of growth within four weeks.
Fibrous-rooted begonias can be grown from seed in early spring. Sow seeds onto moist, seed or multi-purpose compost. They need light to germinate, so don't cover them. Place in a propagator with a lid or cover pots with a clear plastic bag or cling film to retain humidity.
Foliage begonias such as Begonia rex can be easily propagated by leaf cuttings.
Foliage begonias can also be divided – this keeps the plant growing healthily, as well as giving you a new plant for free.
Growing begonias: problem solving
Powdery mildew can be a problem for begonias from May – especially for yellow-flowering types. This fungal disease spreads by spores, so good hygiene should reduce the chances of attack. To prevent the problem space plants out well and ventilate greenhouses. Some gardeners spray plants with a systemic fungicide in May to prevent the problem.
Vine weevil can be a problem with pot-grown begonias.
Find out how to prevent begonias and other bedding plants from becoming leggy, in our Quick Tips video:
Advice on buying begonias
- Begonias are not hardy so if you buy plants or tubers in spring, you will need a warm, bright place in which to grow them before you can plant out in May, after the last frosts
- Begonias like dappled shade, so make sure you have the right spot in which to grow them
- You can buy begonias at nurseries and garden centres, but for more unusual varieties buy online
Where to buy begonias
Begonia varieties to try
Begonia 'Inferno' – a tuberous begonia that provides months of bright orange, weather-resistant flowers. It doesn't need deadheading. Height x Spread: 35cm x 35cm
Begonia x tuberhybrida ‘Giant Picotee Mixed’ – tender perennial with serrated leaves and large ruffled pink, apricot or yellow flowers from July to October. H x S: 30cm x 30cm
Begonia ‘Illumination Series' – cascading flowers in bright colours, weather-resistant flowers. Ideal for a hanging basket. H x S: 60cm x 60cm.
Begonia semperflorens – tender perennials grown as annuals. Small plants with fibrous roots ideal for summer bedding displays. Pink and white flowers. Leathery, shiny green leaves. H x S: 15cm
Begonia rex – grown for its large silver and green foliage that has a rusty brown underside. Tender so needs to be grown as a house plant. H x S: 50cm x 50cm
Begonia luxurians – the palm-leaf begonia. It can be grown as an impressive house plant in a shaded conservatory, and can be put outside in the summer. H x S: 3m x 1m
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