| The word that springs to mind with begonias is
'variety'. Some of gardening's most exciting flowers and startling
foliage can be found within the 900 species and many more hybrids
that comprise this most versatile genus.
Begonia
types
Tuberous
begonias are the splendid showstoppers with their huge double
blooms in an array of dazzling colours including shades of red,
orange, pink and pure white. These superb plants are best suited
to the protection of a conservatory or hothouse and include varieties
which grow erect and cascading types ideal for hanging baskets.
Hardier tuberous begonias have also been bred for protected garden
positions.
Rhizomatous
begonias produce their graceful flower clusters, attractive foliage
and roots from a creeping food-storing rootstock known as a rhizome.
Rex
begonias have insignificant flowers but wonderful, decorative
leaves of many forms and colours, some displaying a dramatic metallic
sheen. They grow best in a well-lit spot indoors and their need
for humidity makes them ideal terrarium plants.
Shrub-like
begonias are also grown for their wonderful foliage but are best
suited to the garden.
Cane
begonias, also known as 'angel wing' begonias because of their
distinctive leaf shape, are best as garden plants or tub specimens,
sited where they can receive morning sun. The bamboo-like stems
of some varieties can rise as high as two metres each spring,
bearing large clusters of attractive, drooping flowers from mid
summer to late autumn.
Trailing
or scandent begonias are suited to growing in baskets, hanging
outside with protection from direct sunlight.
Bedding
begonias |
|
Trailing
begonia in hanging basket |
Bedding
or 'Semperflorens' begonias are the popular, hardy little fibrous-rooted
plants, sold as seedlings in punnets, which grow cheerfully in
full sun and looking their best planted in a mass. Patterns can
be created by designing beds combining different flower and leaf
colours. Leaves can be bronze or green, while flowers range from
white to red.
Cultivation
Originating
in the shaded protection of tropical and subtropical forests,
begonias will not tolerate frost, and most dislike direct sunlight
except for some morning sun. This means that in frost-prone areas
they should be grown under the shelter of shrubs or trees, under
verandahs and pergolas or in containers which can be moved to
protected spots, while bedding begonias should be treated as annuals.
The
succulent nature of begonias means that they are able to store
moisture and need less frequent watering. However, they prefer
a humid environment with adequate ventilation to avoid diseases,
and getting this balance of moisture and ventilation just right
is the key to success. Plants grown indoors will benefit from
grouping plants together, occasional misting and by placing shallow
containers of water nearby to increase humidity.
Larger
plants grown in the garden will need staking and shelter from
drying winds.
Propagation
Softwood
cuttings of tuberous begonias should be taken in spring from shoots
about 10 mm above the tuber when the plant has grown about 50
mm high. They will need plenty of humidity and rooting hormone
powder will help them strike.
Most
begonias can be propagated from leaf cuttings, which can be as
simple as inserting a leaf into a damp propagating medium. Larger
leaves can be struck by cutting small slits across the veins on
the underside of a leaf and pinning the leaf down so that it remains
in contact with the mix. New plants will emerge from each point
where a cut has been made.
Leaves
may also be cut into small chunks, each piece containing a vein.
Cane-stemmed
begonias should be propagated from pieces of stem with three leaf
nodes, cutting above and below the outermost nodes and inserting
these pieces into a medium. New leaves will shoot from the top
node.
Rhizomatous
types can be propagated by cutting the rhizome into pieces about
25 mm long or more and burying them horizontally in the propagating
medium.
Bedding
begonias may be propagated by dividing older plants or tip cuttings.
All
begonias may also be propagated from the fine, dust-like seed,
which should be bulked out with sand and sprinkled onto seed boxes
or punnets, which are then kept warm, damp and undisturbed.
Pests
and diseases
Most
problems with begonias involve moisture, either too much or too
little of it. Watering should be reduced as plants approach dormancy.
Because begonias grown indoors or in a conservatory prefer high
humidity, the problem most likely to be faced is powdery mildew,
indicated by a dusty, greyish coating on the leaves. Botyritis
appears as a greyish-white mould on dead leaves which eventually
spreads to living parts of the plant. Both these diseases can
be controlled by spraying with a fungicide such as Baycor, but
they are indications of insufficient ventilation.
Apart
from an occasional nibble from weevils, insects do not normally
pose a threat to begonias. Mites can be a problem with tuberous
begonias, but this indicates that the growing environment is too
dry and there should not be a problem if humidity is adequate.
Further
reading ...
Growing
Begonias by Peter Sharp. Kangaroo Press, 1998.
Growing
Tuberous Begonias in Australia by Ralph Willsmore.
Five Star Press, 1994.
|
