Exotic and beautiful - Begonia Rex

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Begonia Rex HybridBegonia Rex Hybrid

Begonia Rex Cultivars are prized for their dramatically patterned and intriguingly shaped leaves, and they are just as at home in a shady, humid garden as they are growing as an indoor pot plant. Gardeners of all generations just cannot resist their unusually textured leaves, and today there are countless gorgeous varieties to choose from.

Begonia rex is a tropical plant which originated in the forests of northern India, and it is an interesting story how this begonia arrived in England. It is recorded that in 1856, when orchids were being shipped from India to England, amongst the orchids they found a strange little plant with interestingly patterned leaves - a Rex begonia.  Later on, different varieties of the plant were found in the Andes Mountains, and Richard Pierce, who documented most of them , noted their unusual colours like yellow, red and orange.

These small plants excited botanist’s who continued to grow them, and today their allure continues, and breeders have ensured that there are hundreds of hybrids, which are often given fancy trade names, and as a result, you might find the same plant with two different names in different garden centres.  One interesting and beautiful begonia that's often included with the rex begonias is Begonia masoniana commonly called “Iron Cross Begonia.” This beautiful plant was introduced into cultivation in 1952 and has beautifully puckered leaves with a dark cross in the middle, and is available in black and various other colours. 

Despite its exotic looks, the rex begonia is begonia actually easy to grow, and once you have one, you will want to collect all the varieties you can find, and there is a fascinating selection to choose from, with variegations in shades of green, red, pink, purple, silver, and brown. The small flowers are small and incidental, and it’s usually recommended that you cut the flower stalks out to allow the plant's energy to go into growing new leaves, rather than flowers.

Begonia 'Silver Queen'Begonia 'Silver Queen'

In the Garden & Home:

Begonia rex, with its colourful foliage is one of the most interesting indoor plants around. Dress it up by growing it in a container that complements the colours of its leaves, and depending on the variety, that may mean purple, pink, red, silver, or black.

Because it's a relatively short houseplant, it is perfect to place on work desks, or as a decoration for dinner table settings, and its variegated foliage makes it a perfect contrast plant when viewed against other houseplants. To really play up the unique qualities of begonia rex, pair them with solid green plants with different textures or forms. It also grows easily in large terrariums.

In the warm, frost free regions of South Africa, this begonia looks great outdoors in shady parts of the garden, but the most popular way to display rex begonias outdoors is to collect and group them together, each in its own pot.

Begonia rex has many good bedfellows in the garden, like: Blue Wishbone Flower (Torenia), Creeping Jenny (Lysimachia), Boston ferns, especially the golden one, Leatherleaf Fern (Rumohra adiantiformis) New Guinea Impatiens (Impatiens hawkeri), Coleus (Solenostemon), Wandering Jew (Tradescantia zebrina), Creeping Velvet Grass (Holcus mollis 'Albovariegatus'), Coral Bells (Heuchera), Fuchsias Creeping Mazus (Mazus reptans),  Sedges (Carex), Spurflowers (Plectranthus), Peace Lily (Spathiphyllum), and Polka Dot Plant (Hypoestes).

Begonia 'Emerald Princess'Begonia 'Emerald Princess'

Cultivation/Propagation:

Begonia rex can be temperamental indoors, until you find the right place for it, and you just have to move it around until you find the right conditions and balance for your plant. Indoors, it requires good humidity and even watering.  It can take less light than other begonias, but still requires bright filtered light indoors, and even performs well under fluorescent lights. The only way to know what your plant wants is to watch it as it adjusts to its new surroundings. If it's flourishing, continue with what you are doing, but if it becomes droopy, it probably needs more frequent watering, and if growth becomes lanky, move it into a brighter position. Eventually, you'll figure out the right balance. 

High humidity (more than 50 percent) is crucial to keeping your indoor begonia rex happy, and if humidity is too low the leaf tips will turn brown and dry.  In humid regions this is not a problem, however, in the drier regions of South Africa, to create a humid climate around your begonia rex, it is best to place the pot in a large drip tray filled with water and pebbles. The pebbles will ensure that the pot stands above the water, while allowing evaporation to take place, and thereby increasing humidity. Clustering several pot plants together will also help to increase humidity. Often mist spraying the leaves of tropical houseplants is recommended to increase humidity, but in the case of begonia rex spraying the leaves can lead to spotting, and is therefore not recommended. 

Like many indoor pot plants begonia rex likes to be a little bit pot bound, but if it is growing vigorously, repotting each spring into a pot one size larger than the one it is currently growing in will ensure that it has plenty of soil to develop in. If you are re-potting, a peat-based potting mix is ideal for begonia rex. Large or gangly plants can be pruned lightly into shape, and rotating the pots regularly will ensure that the plant grows more symmetrically

If you are growing begonia rex outdoors, if you can provide them with bright indirect light, humid conditions, and rich, aerated soil like that found on a forest floor, you are sure to be successful, and these tender, evergreen perennials will flourish and spread from their creeping rootstock.  They are sensitive to big fluctuations in temperature, and do not tolerate temperatures below about 13°C.

Too much water and fertiliser is the kiss of death for begonia rex, and soggy soil and prolonged wet leaves and stems can lead to rot. If you keep these points in mind when caring for your plants, it will be smooth sailing.

Plants should be watered when the soil in outdoor beds or pots feels dry, but don’t wait until the plant starts to wilt before watering, however, it is always better to keep them a little too dry, rather than too wet. During the winter months, watering must be reduced.  Begonia rex is not a heavy feeder and you can fertilise as little as once or twice a year, with a liquid pot plant fertiliser, mixed at half strength. Don’t feed at all during the winter months.

The other key to success with rex begonias is tap-water quality. That’s because “hard” water with high mineral salt content causes leaf edge burn because they have no mechanism to deal with salt loads. When given salty water, they pump it to the leaf edges, where it evaporates, leaving these same salts at the pores. The accumulation burns the leaf edges brown and dead.” If you live in an area with hard tap water, switching to distilled water or rainwater will fix this.

Large clumps can be divided in spring, ensuring that each portion of the rhizome bears one or more growing points.

Problems, Pests & Diseases:

Bacterial leaf spot, mildew, and botrytis can occur if the leaves stay wet for long periods, and root rot can be a problem in wet areas. To avoid these issues, be sure your begonias are in well-drained soil and water them sparingly.

If mealybugs, aphids, and caterpillars become a problem, an insecticidal spray will take care of the issue. Handle slugs and snails by placing slug bait near your plants.

Warning:

Begonia rex is toxic to dogs, cats, and horses because it contains soluble calcium oxalates. Clinical signs include: kidney failure (in grazing animals) and vomiting and salivation in dogs and cats. The most toxic part is underground. If you suspect your pet may have ingested a potentially toxic substance, call your local veterinarian as soon as possible. It goes without saying that small children should always be supervised when around houseplants, and in the garden.