It’s countdown to show time for begonias
There are quite a few jobs to do before the first of the autumn events gets under way
We grow our large double-flowered varieties in 20cm (8in) pots. A sturdy stake is placed at the back of the plant and the stem is secured to it in several places as it grows. Plants have a regular high-nitrogen feed each week, diluted as per the manufacturer’s instructions.
B e careful with watering from now on, giving additional water only if required to those plants that are drying out. The greenhouse glass has been treated with light-reflecting Coolglass to stop the plants burning, and
I also open the windows and door to reduce the heat.
I remove all flower buds until 42 days before the flower show, and then select a flower bud about 2.5cm (1in) in diameter. This is the bud which will develop into the bloom.
From then on I have to be careful that nothing passes over the bud as a loose sleeve or hand touching it may break it or, as the bud opens, damage or bruise a petal. At this point I change the liquid feed to a low-nitrogen, high-potash feed for the last six weeks, which should encourage a 23cm (9in) bloom.
Begonia rex are just as demanding, where preparation for the flower show starts weeks before. Every time I look at the plants I will remove any discoloured leaves. Feeding regularly with a liquid food with trace elements and seaweed extract will give good leaf colour and strong growth.
Begonia rex hybrids sometimes flower during the summer and autumn – if it distracts from the overall beauty of the plant I remove the flower stems before the show.
All plants entered into flower shows should be free from pests and diseases. Close monitoring by regular inspection of the plants is vital and I have time to treat any pest that may appear now. Keeping a steady, ambient temperature through the day with a slight temperature drop at night is acceptable, but if the temperature drops too low at night there is a high probability of mildew.
The plant should have an even growth all round, with no holes in the canopy. However some types do have an obvious front which should face the judge. On show day I turn the pot many times until I decide which is the best side and, if required, remove a leaf to balance the plant. Some begonias, like ‘Red Tempest’, exhibit themselves with little or no help from me!
The plant pot should be kept clean and free from debris for two reasons. Firstly, dead and decaying matter on the top of the compost can
harbour pests and spores of diseases. Secondly, applying liquid feed can cause a white calcium deposit to grow around the bottom (and top) of the pot. Remove this before the show with spirit vinegar and a scourer pad. If this does not work, I change the pot.
Several days before the flower show, every plant must be individually packed into a secure box with pieces of garden fleece cut into strips wide enough to contain and protect the leaves.
One more top tip – take small wooden wedges to the show to place under the back of the pot base. This will raise the plant, giving a better presentation to the judge.