Growth Habit

•  Tuberous begonias can be upright or trailing, depending on the variety. Tuberous begonias can be grown in the ground under trees or in shady parts of your garden, or in containers placed in shady areas of your porch, patio, or yard.

Staking

• Trailing varieties of tuberous begonias are meant to creep, so they do not need staking. Upright tuberous begonias, however, can benefit from staking so the flower stems stand tall to make it easier to viewing the beautiful flowers. When upright varieties are 4 to 6 inches tall, place a narrow bamboo or metal stake in the soil near the main stem. Fasten the stem to the stake with plant ties or garden twine, being careful not to damage the stem. Add more ties to provide ongoing support as the plant grows.

Watering

•  Begonias need moist soil, but are very susceptible to rotting under wet conditions. Water slightly every few days, or when the soil dries out. Water less frequently if you have regular rain. Water containers of begonias more frequently, but always be cautious to not over water, or their stems might rot. Always water around the tuber, not directly on it, to repvent water from pooling in the tuber.
• Tuberous and fancy begonia leaves can be stained and discolored by water. Avoid watering with cold water or tap water that is high in minerals, and when possible, use distilled water instead. 

Fertilizing

• Amend your soil with compost before planting begonias in the ground. Begonias are heavy feeders, so fertilize plants in the ground and in containers monthly with an organic balanced fertilizer (Look for 20-20-20 fertilizer mixes). For container begonias, use a liquid fertilizer, so the nutrients are more readily available.

Mulching

• Since begonias are susceptible to rot due to wet conditions, mulching should be done cautiously. Use bark mulch around plants to preserve soil moisture and prevent weeds from growing. Keep mulch a few inches away from the succulent begonia stems to prevent them from rot. Begonias in containers don't need mulching.

Trimming & Pruning

• To encourage fuller, bushier growth, pinch back newly-formed growth tips when they are about 3-6 inches long. Repeat monthly until mid-summer. For fewer, larger flowers, pinch off new young stem growth while leaving new buds to grow into flowers. Pinch back to the second healthy bud from the tip. Deadhead regularly to clean up the tuberous begonia's look, and to remove rotting old flowers that might infect the plants.