How to grow Begonias

Begonias

 

You might be most familiar with the sun-hardy bedding begonias, the ‘wax flowers’ whose red and white blooms shine on through hot weather. 

 

But there are many other types of begonias, some with beautiful patterned leaves as well as those simple, charming, waxy flowers.  


Some begonias make lovely ‘fillers’ in shady, frost-free gardens, others are best suited for pots and baskets. Here’s a quick run-down of a few of the members of this be group of plants.

 

Cane-stemmed begonias

These begonias (Begonia coccinea) can grow to 2m with straight stems and showy clusters of pendulous waxy flowers from mid-summer to late-autumn. Called ‘Angel Wing’ because of the shape of the heart-shaped, often speckled foliage, they make fine garden plants in sheltered, frost-free gardens. Their form and foliage makes them perfect plants for mixing into borders or using in pots in courtyards and balconies. Allow morning sun, take care not to over-water and prune mature plants hard in late-winter to encourage new growth from the base. Make new plants from stem cuttings.

 


Photo - ntdanai/Shutterstock.com

 

Rex or king begonia

This begonia is grown for its large foliage, which may be coloured, patterned or have an intriguing metallic sheen, rather than for its insignificant flowers. Bright and unusual shades of green, pink, red, silver, purple and grey combine to make bold patterns on the leaves. Grow rex in pots and baskets in a well-lit position indoors. Because of their succulent leaves, begonias store moisture and need less frequent watering. Indoors they need high humidity and good ventilation to avoid disease problems. To boost humidity, sit them in a tray of pebbles and water. Dry air will cause leaf margins to brown.

 


Photo - Eve81/Shutterstock.com

 

Tuberous begonias

These are grown for their huge colourful blooms and are best in a cool shade house, with part or filtered shade, and good ventilation to discourage powdery mildew. There are erect varieties suited to pots, and cascading varieties suited to hanging baskets. As the flowering season approaches water them with Phostrogen, but don’t over-water as tubers grow better if kept slightly dry and are susceptible to rotting if kept too wet.

 


Photo - Marie C. Fields/Shutterstock.com

 

Elatior begonias

Charming begonias for indoors, these are grown for their clusters of pretty pastel flowers. They are happy to grow for a season or two near a bright windowsill or kitchen table. Avoid wet or waterlogged soil. Flowers come in pretty soft shades of peach, lemon, white, pink and apricot. Feed with liquid feed and a sprinkle of controlled release. They are not long-lived but we think they’re better than a bunch of flowers! You’ll find them in the indoor plant section at your local nursery.

 


Photo - sakhorn/Shutterstock.com

 

Bedding or Wax begonias

This small-growing ‘bright as a button’, old-fashioned wax begonia (Begonia semperflorens) is making a little comeback as a hardy bedding plant for borders and pots. It never stops flowering and lasts one season. It comes in red, white and pink flowers with green or purple leaves. B. semperflorens is great for pots. Watch for powdery mildew fungus on the leaves, treat with a fungicide. To get an extra year out of the plants, try cutting it back over winter, top with straw, keep it dry and it should grow back in spring.

 

 

Photo - joloei/Shutterstock.com

 

Hanging begonias

‘Bonfire’ (Begonia boliviensis) has exotic flame orange-red flowers with interesting serrated green leaves with a red margin and compact habit. It happily grows to 45cm and will flower continuously through to late autumn. It is very robust and will thrive in hot dry weather in a window box, hanging basket, or in the garden as a border. Feed with liquid feed. Plants die back over winter, re-emerging in spring.

 


Begonia 'Red Dragon'. Photo - Luisa Brimble

 

Begonia care tips

Begonia biggest enemy is frost. Planting them under other shrubs will help protect them. Pots can be brought close or into the house over winter in frosty regions.

Use the best potting mix available and add 20% perlite to lighten the mix, which allows better drainage and and reduces the risk of fungal problems during wet weather.

Powdery mildew on leaves can be controlled with Baycor.

Prune plants whenever they get leggy.

Watch for green looper caterpillars that find the taste of tender begonia leaves tempting.


More begonias

Check out the new begonia garden at the Royal Botanic Gardens in Sydney (Bed 31), and if you like what you see, consider joining the

Begonia Society to meet with friends to learn more about begonias.

NSW Begonia Society: (02) 96791386

Victorian Begonia Society: (03) 53362125

Queensland Begonia Society: (07) 3359 4319

South Australian Begonia Society: (08) 8264 6490

 

Text: Sandra Ross

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Comments

Joy Young commented on 25 Sep 15

I live in Tasmania and trying to buy Cascading Begonia tubers, can you assist

thank you

About this article

Author: Sandra Ross