70 (May/June 2003)
Growing Begonias of
All Kinds in England
by Terry Tasker
I have grown and shown double tuberous begonias for
twenty years, but over the past six years or so I have grown more species
begonias than I have double tuberous. At one time I grew over two hundred
pots of double tuberous begonias for showing.
My attention is now drawn to the decorative leaf,
textures, shapes, colours, growing habits and places of origin of species
and hybrid begonias. A whole new world has opened up for me in this
fascinating hobby. My collection now consists of two hundred species and
three hundred plus hybrids/cultivars. I thirst for more.
Rhizomatous begonias are in general, the most popular
of all the begonias I have come across. Their almost endless shapes,
colours, textures, growing habit and ease of keeping (with a few
exceptions) makes them ideal for the beginner to start growing begonia
species or hybrids. I have found they need free draining compost,
nutrients, water, (but not too much) light and slighter cooler conditions
then other begonias.
I do not over pot my plants, as they grow better when
root bound. If I have to pot on I only use the next size pot. I feel
plants get stressed when over potted.
I mist my plants with a foliar feed in spring; this
helps to stimulate action of new growth. I still use urea and nitrate of
potash at the quarter strength, on my established plants as it is
recommended for double tuberous with a slight variation in that I add
Epsom salts to the mix one tea spoon to a gallon of spray. In summer they
are fed with a very high potash tomato teed. I water or spray in the
morning so the plants are dry by late afternoon/evening. My green houses
are always set, in winter, at 70°F plus purely because 1 have some very
rare and difficult to keep begonias and humidity is at 50% rising to 70%
The heat is given by two gas boilers and pipe from
domestic supply; no fumes are given off just heat. Don't be put of by
these temperatures; many will tolerate as low as 45°F in winter. Growing
begonias or any plant is just common sense. Study your subject and give
then what they require.
One thing you must be on the look out for is signs of
powdery mildew on the foliage. Remember prevention is better than cure. I
have always followed a practice of spraying any insecticides/pesticides or
fungicides every two weeks. Get into a routine; it pays dividends in the
end. And yes, I do have air circulating fans as well.
Here are two more photos of Terry
Tasker's plants. We cans see from the photo above that B. gehrtii, center,
grows as well in England as we saw it did in Portugal a few issues ago.
Below are his many beautiful Rex cultivars.
To get good growth out of my begonias they need light.
Too little light and they grow leggy and will never look right. Too much
and the plants will scorch and possibly wither and die. I grow them in a
shade that you can just about see a shadow on the plant from your hand
when the sun is out. This seems to be just right for them.
As the plants are growing, make sure you turn the pot
each week; the plant will grow even and give a more pleasing allround
shape to it.
Once the plants are growing well I will propagate from them.
Rhizomatous begonias are, I feel, one of the easiest to take cuttings
from. There are several methods in which this can be done, but one of the
more popular ways 1 use is my method for small eyelash type such as
B. 'Red Planet' and B. 'English Lace'.
Prepare a seed trays a few days before by cleaning
thoroughly and filling with cutting compost water in with a weak solution
of fungicide, place the lid on the tray and put on to propagating bed set
at 75°F. This will warm up so the cuttings are not put into cold
Choosing a plant from which I need to propagate I cut
off a leaf together with its stem, about two inches in length. Dip the
leaf into a solution of fungicide to make sure it is free from disease.
Insert the stem into compost about 1/2 inch and firm. Continue until the
tray is full. Do not let plants over lap. The surface of the leaf must not
be allowed to touch the compost, as this would risk decay. I do not use
rooting powder; if the plant is healthy there is no need.
I cannot stress how important it is to be clean as
possible when taking any cuttings or setting seed.
Before putting on the cover, water the cuttings with a
suitable fungicide, which has been allowed to stand for a few hours to
come to room temperature. Place the tray into the propagator. Give then as
much light as possible; if you have grow lights, give the cuttings sixteen
added hours of light until rooted then reduce to ten.
Spray as required keeping humidity high. I have found
that putting 'Maxicrop' original seaweed extract, which contains a growth
stimulant in my sprayer, is excellent for any type of cuttings. If you do
not have grow lights do not be put off; it just takes a little longer
After 3 to 5 weeks (depending on variety) small
plantlets will appear from below the compost all round the bottom of the
At this stage I start to acclimatise the young plants
by removing the propagator top for a few hours a day until they are ready
to be potted to their first pot. Carry on foliar feeding and do not
overwater the compost Pot on as required.
The compost I have been trying for the last six months
is a peat substitute; it is a very fine, but coarse, coconut fibre.
For rooting begonias I have had nothing better in all
the years I have been growing. In my opinion it is ideal for getting your
cuttings/tubers a good start into life.
Up to date, using this method, I have taken over two
thousand cuttings, losing twenty. I need to grow so many as I love to show
my plants. Try the above and publish your findings in the bulletin. You
might find a better variation.