Presentation on Begonias - June meeting 2018

1. Begonias

2. Summary
Looking for something to add colour and interest to your garden or room? Begonias
are an excellent choice.
Begonias are perennial plants known for their spectacular flowers and foliage.

3. The genus Begonia (which is both the botanical and common name) belongs to the
Begoniaceae family. There are over 1200 species of Begonia, growing best in
tropical or sub tropical climates.
Begonias are an obvious choice to grow in a
semi shaded or shaded area.
They are well suited to a wide variety of
climates, though excessive cold (eg. frost),
direct sunlight or excessive dryness can kill or
severely damage most types of begonias.
Many will grow well as indoor plants; some
are more commonly grown in a shade house
or fernery; and others are grown as bedding
plants.

4. Growing Conditions
Most begonias respond best to warm, moist conditions. The ideal temperature
range is 15 to 26 Celsius though most will
tolerate temperatures as high as 40C and
as low as 5C - some even lower.
All begonias prefer well drained soil rich in
compost or organic matter and some like
some degree of shade. Semperflorens and
tree begonias however, tolerate more light
than the others.
All grow well in semi–shade or half–shade.

5. Fertilise with a liquid fertiliser at half the recommended strength, but apply twice
as often. The soil should always be moist but never saturated or bone dry. Roots
will easily rot if they become too wet.
Foliage will shrivel and thin if the soil
becomes too dry. Mulching is a good way
to help maintain soil moisture.
Most begonias grow well in pots but be
aware that it is more difficult to maintain
an even soil moisture level with a container
grown plant. Pot plants dry out quickly and
over-watering is a temptation.

6. Varieties
Cultivated begonias are divided into nine major groups:
• rhizomatous begonias
• rex begonias
• semperflorens begonias
• cane–like begonias
• shrub–like begonias
• thick–stemmed begonias
• trailing/scandent begonias
• tuberous and semi–tuberous begonias
• elatior begonias

7. Rhizomatous Begonias
This is the largest begonia group with hundreds of
thousands of hybrids. Most have rhizomes which run
along the surface of the ground whilst others are erect or
underground.
Most are grown for their interesting leaves and compact
growth but they have the added bonus of a massive
display of flowers, usually winter/spring.
Although some rhizomatous begonias will grow well in
the garden, they are shown to best advantage when
grown in pots and mature plants make spectacular
hanging basket subjects.
Do not overwater rhizomes, they will do well through winter with very sparse watering and are
happy in the same pot for some years. Propagate from rhizome or leaf cuttings or leaf wedges.

8. rex begonias
These beautiful plants are in fact rhizomatous begonias but are
classified separately because of their distinctive ornamental
foliage and are best grown indoors or in bush houses.
Successful cultivation depends on the use of good free draining
potting mix and attention to the environmental factors of:
• light: grow in a bright location with no direct sunlight
• temperature: any comfortable living temperature is
satisfactory – if you are comfortable so are your
rexes
• humidity: 60% is the ideal – additional humidity may be generated when necessary by spraying
the ground under benches with water or standing pots in trays of wet gravel, ensuring that the
pot bases are clear of the water level
• Keep on the dry side in winter. Rex begonias are susceptible to mildew and preventative measures
are advised; give the plants plenty of space for good aeration, provide good ventilation and keep
moisture away from the leaves

9. semperflorens begonias
Most gardeners will know this one - often referred to
as the bedding begonia, or the wax plant, or perhaps
‘Thousand Wonders’.
Some gardening books refer to them as fibrous–rooted
begonias, but this description fits so many of the begonia groups that it is not really a proper
description here.
‘Semps’, (as they are affectionately known) can be found in many council parks and gardens.
They are widely used in gardens in Europe, and are at their best when they are mass planted.

10. Cane Stemmed or Tree Stemmed Begonias
These are taller growing plants with bamboo like stems,
wing shaped leaves and drooping clusters of flowers.
Foliage is not normally as dense as the ‘semperflorens’
and the flowering not as prolonged; but the large leaves
are often spectacular in both shape and colour.
These are perhaps the most cold-hardy types.

11. shrub–like begonias
The shrub–like begonias are also wonderful
garden plants, and most should bloom
throughout most of the year.
As the name implies, these plants grow into a
shrub–like habit, and can easily be pruned
into shape.
Shrub-like begonias also make good pot specimens
and attractive cut flowers.

12. trailing/scandent begonias
Trailing begonias make excellent specimens for hanging
baskets outdoors as the stems of some species can
grow to 2m or more and they are often used to train up
pillars or posts.
They flower profusely, with flowering periods varying
according to species - some cultivars flowering
throughout the year.
They are easily contained with regular pruning.
They need a sheltered position with filtered, but not direct, sun.
Most trailing begonias have either pink or white flowers. Some have philodendron-like
glossy leaves.

13. tuberous and semi–tuberous begonias
Types of tuberous begonias include upright or
trailing varieties with single, double or ruffled
blooms in tropical shades of pink, yellow, orange,
red and white. The gold, purple, green or
burgundy leaves are nearly as attractive as the
flowers.
Although tuberous begonias are shade-loving
plants, they also require a bit of morning or late
afternoon sunlight. A location in dappled or
filtered light also works well, but the plants won’t survive midday sun or
heat.

14. elatior begonias
They are most commonly grown as indoor plants where they enjoy bright
but indirect light and shelter from winds or draughts though they do need
good air circulation around them to avoid powdery mildew attacks.
If grown outdoors then avoid more than an hour or so a day of direct light
- then preferably morning rather than late afternoon sun which will scorch
the leaves.
They thrive in African Violet soil mix, but you can make your own.
Mix 2 parts potting soil, 2 parts leaf mould, 1 part perlite and one part aquarium charcoal.
Add a handful of fir bark to the mixture and mix well. Moisten the mixture before using.
Cut Elatior begonias back to a height of 2 to 4 inches after blooming. This forces a new growth
and revitalizes the plant. A new flush of blooms typically follows within a few weeks.
Rooting cuttings in a vase of water or moist sand produces new plants identical to the original.
Pot the cutting in individual pots once roots are 1 inch long.

15. A Selection

20. Questions?