Summary: Begonias are one garden plant that will thrive in shady spots found in every garden, when other plants will not thrive under those conditions.
What will you plant under high-branched trees or on the north side of your house reached only by morning sunlight? What you need is a plant that likes semi-shade, and just such a plant is the tuberous begonia.
Once you understand them, tuberous begonias are easy to grow, and will color the garden from June till frost with a continuous array of magnificent blooms. But you must remember that they thrive in semi – not dense – shade. Although the afternoon sun is usually too hot, three hours of morning sun are necessary for optimum growth. The other prime consideration is soil, which must be well drained and high in organic content. A mixture of 1/3 leafmold, 1/3 peatmoss and 1/3 sandy soil is best. Tuberous begonias in damp, poorly drained locations usually drop their buds before they can open.
Summer Bloom
For summer bloom, start your tubers between January and March – the earlier you start, the larger the plant will be when it is time to set it out in the garden. Tubers should range in size from 1 inch to 2 1/2 inches, but their size bears almost no relationship to the size of the flower they will produce. In fact, huge tubers often result in sluggish growth, whereas magnificent blooms can be obtained from plants with no tubers – those grown from seeds. The quality of the plant and flowers depends on the quality of the parent plant.
Shoots develop from little pink “eyes” found on the top of the tuber. (The top is distinguished by a cup-like depression and the scar made by the old stem. The bottom is round.) If these “eyes” are not visible when you are ready to start your tubers, spread them out in a warm place on a thin layer of peatmoss and moisten occasionally till they sprout. Then plant tubers in a flat, cup side up. covered 1/2 inch and 6 inches apart in a mixture of 1/3 peat, 1/3 sand, leafmold, or if leafmold is not available, 2/3 peat, 1/3 sand. Place the flat in full light at temperature of 60-70 degrees F. Starting tubers in the dark results in weak, leggy plants. Water lightly till growth appears, since the tuber cannot take up much water till its roots develop, When they do, water a little more heavily.
On the upright types, all but two or three shoots should be removed. On the other hand, encourage as many shoots as possible for the hanging basket type. When the plants have three or four full-sized leaves, they are ready to be transplanted to either pots or a garden bed. Place them with the points of the leaves facing front, since the flowers will open in that direction.
Tuberous Begonia Cultural Tips
The rapidly growing tuberous begonia plant will require water frequently. Be careful not to wet the foliage; sun shining on wet leaves will burn them. For maximum production feed twice a month with a balanced fertilizer. The organic base kinds are best because of their slower, longer lasting action. Again, caution is needed. Severe rot can start if fertilizer comes in direct contact with the plant. Decaying plant material left on the stem will also cause rot. At first sign of rot on the stem, cut out the diseased portion and paint the open wound with a thin paste of fungicide. Mildew can be controlled with a sulfur spray. Staking is a must as protection against wind and rain.
In areas where the nights are cool, below 60 degrees F, removing the side female buds will increase the size of the double male bloom. In warmer areas such a step will have no effect.
When the first light frost blackens the leaves, dig up the plants, leaving a ball of soil around the tuber. Cut off the top part of the plant about 3 inches above the tuber, and paint the cut surface with a fungicide like captan. Place the tuber in a cool, dark spot to ripen. In two months clean the soil from the tuber, remove the stem, and place on slightly damp peatmoss. Your tubers are then ready to be stored in a cool place until spring, when again they will lend their color and beauty to the living garden.
by C Lewis
