Winter Flowering Begonias and Gloxinias
Winter Flowering Begonias
Several races of begonia, particularly ‘Gloire de Lorraine’, ‘Optima’ and varieties related to them, are exclusively winter flowering. They can be grown fromrooted in a warm propagator in spring and need to be grown on in a greenhouse with a minimum temperature of 15°C (60°F), in a moderately moist atmosphere and with shade from direct sunshine. Even in winter a temperature of 13-18°C (55-65°F) must be maintained.
‘Gloire de Lorraine’ and other varieties of its type produce large sprays of small pink flowers not unlike those of Begonia semperflorens, so popular for summer bedding. Their roots are wholly fibrous. ‘Optima’ is taller and has larger, single pink flowers and the roots are partly fibrous, partly tuberous owing to their hybrid origin. This makes them more sensitive to overwatering in winter, when the needs to be kept moist but never sodden. This is made easier if the potting is really porous, with plenty of peat and/or leafmould and sand.
“An Exotic Atmosphere”
Begonias and Gloxinias
Tuberous-rooted begonias and gloxinias are two of the most gorgeous, exotic plants that can be grown easily in greenhouses, conservatories or sunny windows. February is a good time to start, either with seed or with tubers; you can begin later, but flowering will then be delayed.
Tubers should be raised in a greenhouse maintained at an initial temperature of 15-18°C (59-65°F). Bed them side by side in moist peat in shallow seed trays and keep them moist until they have two or three leaves each. Then lift them carefully out of the peat and transfer them singly to 12-15cm (5-6in) pots containing any good soil-or peat-based potting compost. Keep the tubers almost on the surface.
Once potted-on, both begonias and gloxinias like to grow in a temperate atmosphere. They do not like great heat or intense light. The temperature range should be 15-21°C (59-70°F) with the sunny side of the greenhouse kept shaded in summer. The begonias can also be planted outdoors from June to September, though it is best to limit yourself to plants producing medium-sized flowers since the larger flowers tend to get battered by wind and rain.
Water the greenhouse plants fairly freely in spring and summer but less and less from early autumn and not at all in winter. By November they can be tapped out of their pots, the remaining stems and leaves cut off and the soil shaken from the roots, after which the tubers can be stored dry in any cool frost-proof place. Alternatively, leave the tubers in their pots and lay these on their sides in a frost-proof place so that no water gets into the soil. There the tubers can stay until it is time to start them again the following year.
If you decide to grow begonias and gloxinias from seed you must be very careful when sowing because the seed is very fine, almost dust-like. It is best sown in pans filled with a peat-based seed compost made very smooth and level so that the tiny seeds do not drop down into crevices and get smothered. After sowing, the seed may either be covered with the lightest peppering of fine silver sand or left uncovered with a sheet of glass laid over the pan and a single sheet of newspaper laid on top. Pans are best watered by holding them for a few moments almost to their rims in a basin of water; the moisture then rises from below and the surface is not disturbed. A temperature of 18-21° (65-70°F ) will ensure good germination but it may be up to four weeks before all theappear.
Prick out the seedlings while they are still tiny into a peat compost no less fine than the one you used for sowing. A few weeks later the seedlings can be potted singly in small 6cm (2-1/2in) pots using a slightly richer mixture which may contain a little soil if preferred. As these pots become filled with roots, move the plants on to larger pots. When the tubers start to form, they should be kept quite close to the surface when repotting, only just covered with soil. Continue to cultivate exactly as for plants grown from tubers.
There are many other types of begonia which do not make tubers and therefore cannot be stored dry during the winter. Some actually choose winter as their flowering season and are among the most beautiful plants then in bloom. This group includes `Gloire de Lorraine’, with dense sprays of small pink flowers, the larger-flowered ‘Optima’ and other associated varieties. Grown from cuttings of young shoots rooted in a warm propagator in spring, they require similar conditions to the summer-flowering begonias except that they are never deprived of water and are kept growing throughout the winter in a temperature of 15-18°C (59-65°F).
The ‘Rex’ begonias, and also a species named Begonia masoniana, often called ‘Iron Cross’ because of the black cross-shaped marking on each leaf, are grown for their foliage. In the ‘Rex’ varieties the leaves are large, heart-shaped and richly coloured — green, silver and metallic purple. These begonias are not difficult to grow, they will put up with a lot of shade and will survive even when the temperature falls to 10°C (50°F), but they are happier with a few degrees more. They should be watered moderately, even in winter, and can be increased by division when repotting in spring.
There are also numerous species, such as Begonia manicata with large loose sprays of pink flowers, Begonia haageana with leaves green above and light purple beneath, Begonia lucerna with sprays of large pink flowers and Begonia fuchsioides with long stems that can be trained to wires or canes, all of which are beautiful in both flower and leaf. They need very much the same conditions as the tuberous-rooted kinds except that they must be watered moderately throughout the winter and kept in a temperature which should never fall below 10°C (50°F).