Horticulture Magazine

Begonia Plant Care & Growing Tips

bright red wax begonias in the garden

Begonia Overview

Official Plant NameBegonia
Plant TypeAnnual Flower / Perennial Flower
Native AreaSouth America, Central America, Central Africa and South Asia
Hardiness RatingH2 (sometimes hardier)
ToxicityToxic to pets
FoliageVaried genus
FlowersBright blooms in various colours
When To SowMarch, April, May, June
Flowering MonthsJune, July, August, September
When To PruneJune, July
Sunlight

Preferred
Partial Shade

Exposure
Sheltered

Size

Height
0.1 – 0.5M

Spread
0.1 – 0.5M

Bloom Time
June – September

Soil

Preferred
Loam

Moisture
Moist but well drained

pH
Neutral / Mildly Acidic

The ever-popular ‘Begonia’ is neither a plant nor a flower – it is a genus comprising of over 1,800 species and over 10,000 cultivars. Some gardeners may know Begonias as perennials; others as annuals.

Flower lovers may go crazy about the vast variety of blossoms; foliage enthusiasts are equally fixated on fancy-leaf hybrids. Is Begonia is the Plant Kingdom’s champion genus?

Available in such a mind-boggling array of species, cultivars, hybrids – you name it – that while the Royal Horticultural Society divides indoor Begonias into four groups, the American Begonia Society (Est. 1932) classifies (all) Begonias into no less than eight groups. Tuberous Begonias are renowned for showy blooms in myriad hues while rhizomatous varieties develop large, fancy foliage to the point of stunning foliage.

Then there are cane-like or angelwing Begonias that, akin to bamboo, have straight stems of woody tissue and have attractive, unusual flowers as well as eye-catching speckled leaves.

On the other hand, semperflorens or wax Begonia varieties are also about flowers and leaves – except that they are bedding plants and bear a profusion of brilliant flowers and have waxy leaves. And so it goes.

To top it off, groups are further grouped into classes, and cultivars are arranged in series. For example, cane-like aka angelwing Begonias, semperflorens or wax Begonias, and ‘hairy’ Begonias all fall under fibrous-rooted Begonias. Actually, Begonias are classified according to their rootstock and in addition to fibrous-rooted, there are the aforementioned tuberous and rhizomatous classes. Tuberous Begonias are divided into three groups, one of which, tuberhybrida, is an outdoor annual while two others are greenhouse varieties that flower in winter.

Hard to Pin Down!

Begonias are herbaceous perennials in their native habitats in the tropical and sub-tropical regions of South America, Central America, Central Africa, and Southern Asia. Because they cannot survive a frost, most varieties are grown as annuals in the United Kingdom. However, some varieties can be grown indoors, besides in greenhouses, as perennials. For example, semperflorens or wax Begonias are effectively annuals in temperate regions but can live for several years in tropical climates or controlled environments. Begonia is a genus that is hard to pin down as being this or that – it is more like this and that!

Advances in Begonia horticulture occur at a dizzying pace. Consider semperflorens or wax Begonias and cane-like Begonias. These would best be described as petite and cute varieties for beds and small pots; after all, the plants grow – or grew – to about 15 centimetres and no more than about 22 centimetres at most. How things have changed! Newer cultivars are big, beautiful beasties; they average 40 centimetres and the tallest reach a height of 85 centimetres. What is more, they branch repeatedly so that besides being big, they are also broad and bushy. As for the blooms and the leaves, they are colourful, striking, vibrant – but hey, they’re Begonias!

the texture and pattern of B. masoniana aka ‘Iron Cross’
Nature’s Art: the visually arresting texture and pattern of B. masoniana aka ‘Iron Cross’

Background, Origins & Varieties

The well-known name of one of the most popular plant families memorialises quite an unknown gentleman. Way back in the 1600s, a French ancien regime official by the name of Michel V Bégon served in various ‘intendant’ positions in France’s colonies in the Caribbean. This gentleman was passionate about plants and when he met with naturalist and botanist Charles Plumier, the latter was so impressed with the good intendant that he named a new genus after Monsieur Bégon.

As impossible as it is to cover the varieties of a genus whose species number to 1,800-plus and cultivars exceed 10,000, here is a baker’s dozen comprising of some of our favourites. Yet our selection is also meant to represent at least some of the astonishing depth and breadth in this genus: one variety may be a sight to see in big beds and a related one along a bigger border, while others would be best for a dainty hanging basket on the porch or a petite pot on the parapet.

B. aconitifolia: Bearing attractive slate-green leaves with opposing white streaks or spots, the flower is one of the most feminine in the genus, being pale pink with delicate petals arranged in panicles.

B. brevirimosa: A robust species reaching a height of 3 metres, if anything its foliage is even more striking than the plant, having variegated striping of forest green and a brilliant mauve on broad, chunky leaves.

B. incarnata: Though like most Begonias this species’ leaves are attractive, it is the flower that catches one’s fancy: it is small and hairy and of a deep pink hue, and with a highly irregular arrangement.

B. semperflorens ‘Doublet White’: The olive green waxy leaves are pretty in themselves but the profusion of tiny double blossoms of the ‘Doublet’ cultivar steal the show, with ‘Doublet White’ resembling balls of fluffy snow.

B. masoniana aka ‘Iron Cross’: A stunning B. Rex cultivar, its near-rounded huge leaves are a sight to behold as they are puckered and crinkly and bear a maroon-to-black five-armed ‘cross’ on bright green to emerald green background.

B. ‘Escargot’: Reminding one of a snail’s shell, it has a distinct silvery whorl or spiral on a slate-green background on a massive obtuse-to-rounded leaf whose petiole has noticeable red hairs

B. solananthera A. Dc.: One of the rarer climbers, it has beautiful, smooth wavy, sea-green leaves which are more than matched by clusters of distinctive flowers having irregular creamy petals with a red centre.

B. Summer Jewels Mixed: One of the most charming of varieties and akin to hillside wildflowers, this cultivar spreads and trails, showing off lush green foliage and simple-form flowers in white, and pink and red shades.

B.’Munchkin’: Anything but! only 20 centimetres tall but broad and bushy, the plant has smoky, bronze-green coloured leaves that are crinkly, almost frilled, at the edges, topped off by light green veins with deep red colouring on the underside

B.’Illumination Apricot’: Sunset and flame more than apricot, the gorgeous deep yellow and orange hues of the sprays of single and double flowers atop textured, smoky, deep green leaves make for a dramatic plant.

B. ‘Silver Jewell’: Bearing big broad leaves that are lightly puckered and almost cordate, it is the colour combination that is a work of art: viz. painted straps, streaks, and dapples of silver-to-cream on a deep green background.

B.’Ziggy’: Bred to give stiff competition to roses – or simply be mistaken for a rose! – the ornate and showy flower is feminine and tender, and comes in a narrow range of colours from pink-tinged white to a deep pink, with the pale pink variety being the showstopper.

B.’Regal Minuet’: While the form of the leaves is striking enough, being near-sagittate with toothed edges and a sharp point, the lustrous lamina with a purple-magenta hue and dark star at the base is the eye-puller.

A close-up of Begonia brevirimosa foliage
A close-up of Begonia brevirimosa foliage – that brilliant, almost gaudy, mauve!

Feeding, Care & Growing Tips

Caring for Begonia, as one of the most diverse genera, can scarcely be described in a one-size-fits-all section. That said, three essential guidelines hold good for virtually the entire genus. These are:–

  1. Begonias do not like strong, direct sunlight and do best in indirect or filtered sunlight or bright shade.
  2. They are susceptible to frost and must be protected from it.
  3. They do best with moderate and regular watering but are averse to wet soil

Everything else is a variation on these guidelines, apart from specific requirements, such as minimum winter temperatures.

As understorey plants, Begonias generally prefer indirect or filtered sunlight, but stronger sunlight is necessary for Rex Begonia and its cultivars, keeping in mind that the darker-coloured the leaf, the more it can withstand strong sunlight. Most Begonias do well in temperatures of 18° to 25° Centigrade but fare well in warmer temperatures provided they are kept under shade or a natural canopy. 

The best soil is moderately to slightly acidic of pH 5.6 to 6.5, and of a loose, rich, loamy type. Compost may be mixed with the soil; it should preferably contain coir but be free of peat.

Most tuberous Begonias and other varieties valued for their flowers should be watered at the soil level to preclude fungal infections. Water all Begonias moderately so that the soil stays slightly moist but not wet. Reduce both the frequency and quantity in winter.

Most Begonias prefer somewhat humid environments and do not care for dry conditions. In particular, tuberous Begonias positively require more humidity than other kinds.

Regularly feeding semperflorens or wax Begonias with 5-10-5 or other high-phosphorous fertilizer brings out the best in these plants. But where cane-like aka angelwing Begonias are concerned the best fertiliser is a high potassium one. As for Rex and its varieties, a high-nitrogen fertiliser like 20-10-10 is best! In all cases, the plants should be fed every two or three weeks in the summer growing season.

Pruning Begonia

Whether or not to prune Begonias depends on three variables: the type of Begonia i.e. its group, the climate, and the gardener’s aims and intentions.

Semperflorens or wax Begonias benefit from a pinch-and-deadhead routine. Pinch off buds if flowers and buds are abundant to prevent the plant from going under the weight of its blooms, and lop off spent blooms to maintain vitality.

In the temperate and cool climates of the U.K., tuberous varieties will die back in winter when the mercury dips below 10° Centigrade. At this point, the remaining foliage may be cut back and the tubers dug up, brought indoors, and dried. Similar to bulbs of Amaryllis, Dahlia, etc. these tubers can be kept in a cool and dry place through the summer and re-planted in spring.

In temperate and cool climates rhizomatous and fibrous-rooted Begonias can be treated as annuals if meant as outdoor plants to be grown every year. Or, they can be brought indoors before the approach of winter. To do so, they should be pruned in autumn. Give them a good trim but there is no need to cut them back.

In spring, mature plants may be thinned and sculpted by pruning if there is an excess of stems. Spring pruning is also done to fashion bushy plants. Pinch off or prune selected stem tips to the first or second bud when they are 7.5 to 15 centimetres. Do so twice or thrice every four weeks.

Cane-stemmed begonias are pruned for a dual reason: bushiness at the base and maintenance to a particular height. Cut back the main stem to the desired height, but do not cut off more than one-thirds of the length. Pruning can be done from spring to mid-summer. If you would like your cane-stemmed begonias to attain their maximum heights, do not prune them.

The flower of Begonia aconitifolia, and its speckled leaves
The delicate and feminine flower of Begonia aconitifolia, and its speckled leaves

Habitat & Growing Conditions

For the most part Begonias are understorey plants that grow in the cool and moist conditions of a rainforest canopy in their native habitats, for example, Cameroon and Malaysia. Some tuberous varieties thrive in dry and cool climes like those of the Peruvian Andes. Others grow in the wild on moist, shady slopes.

Begonia habitats are the tropical and subtropical regions of South America, Central America, Central Africa, and Eastern Asia, with Southern China, Ecuador, and Cameroon being particular centres of diversity. Other countries which boast their own ‘brand of Begonia’ include Ecuador, Andean Peru, Brazil, Colombia, Venezuela, Mexico, Cameroon, Equatorial Guinea, India, Peninsular Malaysia, Borneo, Southern China, Vietnam, Philippines, and the Koreas.

A few Begonias are native only to isolated areas in remote locations such as Sao Tome, the Bolivian Andes, and New Guinea; in contrast, Begonia cucullata grows freely across a huge swath of land in Argentina, Brazil, Paraguay, and Uruguay. The famed Begonia Rex cultivars originate from the species which is native to India. Regardless of the species or cultivar, the flowers of this genus are monoecious, that is, a given flower on a plant is either female or male.

Most varieties are hardy to U.S.D.A. Zones 10 and 11. Begonia grandis aka ‘Hardy Begonia’ is a well-known exception that is winter hardy in temperate regions, being hardy to Zone 7.

Propagating Begonia

Fibrous-rooted and tuberous Begonias are propagated by stem or leaf cuttings; however, the process is easier and more straightforward with fibrous-rooted Begonias. Within the fibrous-rooted class it is easier to propagate cane-stemmed varieties by stem cuttings, and semperflorens or wax varieties through leaf cuttings. Whichever method you choose, use a sharp pair of secateurs which has been sterilised with rubbing alcohol.

The best time to propagate by stem cuttings is mid-spring. Cut off a length of 8 to 10 centimetres, preferably of a basal stem. Plant it in a mix of compost and potting soil. Provide bottom heat of about 20° Centigrade. Keep in bright shade and water moderately.

You can propagate by leaf cuttings in spring but if it is unduly cold, wait for the snap to pass. The leaf cutting should have two or more nodes but no blooms. Insert the stalk into a mix of potting soil and compost, and keep in partial shade in a warm location. Water it moderately.

In addition to the leaf cutting method, Rex Begonia varieties are often propagated by a specialised method. Select a leaf that has just matured. From its bottom or lower surface, make a few small incisions along the veins, using a disinfected sharp blade. Place the leaf, lower side down, on compost and peg it or or put light weights on the leaf so that it stays in tight contact with the soil. Keep it in bright sunlight (but not under a hot sun) and water it well. Rootlets will emerge from the cuts in the vein.

No matter which method you use, adding rooting hormone is usually a good idea.

While almost all Begonias can be propagated by stem or leaf cuttings, rhizomatous varieties are also propagated by division. In spring, dig up the rhizomes and divide them such that each piece has at least one, preferably more, growing points. Then re-pot the rhizomes.

‘Doublet White’ flowers that look like balls of fluffy snow
Are those some flowers? Or balls of fluffy snow? Introducing the ‘Doublet White’

Common Diseases & Problems

Begonias can become infested by mealybugs and aphids. You can treat either and both by using products like BotaniGard ES or Safer’s soap according to manufacturer’s instructions.

Aphids are a particular menace because of their rapid breeding and harmfulness. Spraying or rubbing a one-percent solution of Orthene on the infested areas and surrounding parts is probably the most effective way to kill aphids.

Mealybugs on outdoor plants can be eliminated using nature to fight nature. Release ladybugs, lacewings, and mealybug destroyers on the affected plants. These are beneficial insects that prey upon mealybugs.

Rex Begonias are particularly susceptible to nematodes. While many nematodes are beneficial and even kill harmful insects, some are parasites that dwell in soil and destroy plants. Garden Centres usually stock some products for nematode infestation. A few natural methods exist to eliminate nematodes, such as raising the soil temperature by sealing it off, but these cannot be used on soil inhabited by plants. One semi-natural remedy that can be used to put down a nematode infestation is to put naptha mothballs on the soil, and water plants as usual.

Begonias, especially saplings and young plants, are delicacies for snails and slugs so be on the lookout for them and remove or eliminate them promptly so that their numbers do not get out of hand.

While waterlogged soil is harmful to almost all plants, even damp soil poses a threat to tuberous Begonia varieties as dampness can bring about rot. Ensure that the soil is drained well and put containers on tiles or wedges so they are off the ground.

Although Begonias like some humidity, avoid misting them and do not expose them to overly humid environments to prevent mildew.

Frequently Asked Questions          

Are begonias easy to grow?

Begonias are among the easiest plants to grow, especially if they are propagated from stem cuttings or leaf cuttings which is possible to do with nearly all species and varieties. See section Propagating Begonia for details.

Are begonias perennials?

In their native habitats, Begonias are perennials but in the temperate and cool climates of Europe they are annuals unless they are brought indoors to overwinter or kept in a greenhouse. For particulars see sections Types and Kinds and Hard to Pin Down!

When should I plant begonia tubers?

They should be planted in end-winter or early-spring, about one month before the last expected frost. Therefore, they have to be started indoors. Plant them in small containers and expose them to sunlight but protect them from cold. After they have sprouted, in end-spring they may be transplanted and/or moved outdoors.

When To Plant Semperflorens Begonia?

An ever-popular bedding variety, it is best planted in mid-spring via stem or leaf cuttings. See section Propagating Begonia for details.

How should I plant begonia corms in hanging baskets?

Fill the basket with a loose mix of potting soil and compost. Gently tuck the corm into the soil so that its surface and the soil surface are level. Always plant corms concave-side up. Water it well and regularly but do so around the corm – if water collects in the concavity, it may start to rot. Keep the basket in a place where it gets mild sunlight and where the temperature is a minimum of 22° Centigrade.

Do rabbits eat begonias?

This question cannot be answered by a firm affirmative or negative for the truth is that most rabbits will not eat most Begonias but some rabbits will sometimes eat some Begonias. One group of Begonias that repels rabbits more than any other is the semperflorens or wax group.

Are begonias safe for cats & dogs?

Not at all; in fact, Begonia stems are toxic and the rhizomatous part and roots are extremely toxic due to the calcium oxalates in them. Ingestion causes salivation, vomiting, swelling of the snout, and a burning sensation inside the mouth. Any pet that has ingested Begonias should be taken promptly to a vet.

‘Illumination Apricot’ flowers in bloom
‘Illumination Apricot’ is more flame and sunset than apricot, but is as lovely for the bed as for a basket

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